Physiological Parameter Confidence Measure

MULTIPLE WAVELENGTH SENSOR EMITTERS

A physiological sensor has light emitting sources, each activated by addressing at least one row and at least one column of an electrical grid. The light emitting sources are capable of transmitting light of multiple wavelengths and a detector is responsive to the transmitted light after attenuation by body tissue.

Multi-Wavelength Physiological Monitor

A physiological monitor for determining blood oxygen saturation of a medical patient includes a sensor, a signal processor and a display. The sensor includes at least three light emitting diodes. Each light emitting diode is adapted to emit light of a different wavelength. The sensor also includes a detector, where the detector is adapted to receive light from the three light emitting diodes after being attenuated by tissue. The detector generates an output signal based at least in part upon the received light. The signal processor determines blood oxygen saturation based at least upon the output signal, and the display provides an indication of the blood oxygen saturation.

Respiration processor

Respiratory rate can be calculated from an acoustic input signal using time domain and frequency domain techniques. Confidence in the calculated respiratory rate can also be calculated using time domain and frequency domain techniques. Overall respiratory rate and confidence values can be obtained from the time and frequency domain calculations. The overall respiratory rate and confidence values can be output for presentation to a clinician.

Physiological Parameter Confidence Measure

Confidence in a physiological parameter is measured from physiological data responsive to the intensity of multiple wavelengths of optical radiation after tissue attenuation. The physiological parameter is estimated based upon the physiological data. Reference data clusters are stored according to known values of the physiological parameter. At least one of the data clusters is selected according to the estimated physiological parameter. The confidence measure is determined from a comparison of the selected data clusters and the physiological data.

Noninvasive multi-parameter patient monitor

Embodiments of the present disclosure include a handheld multi-parameter patient monitor capable of determining multiple physiological parameters from the output of a light sensitive detector capable of detecting light attenuated by body tissue. For example, in an embodiment, the monitor is capable of advantageously and accurately displaying one or more of pulse rate, plethysmograph data, perfusion quality, signal confidence, and values of blood constituents in body tissue, including for example, arterial carbon monoxide saturation (“HbCO”), methemoglobin saturation (“HbMet”), total hemoglobin (“Hbt”), arterial oxygen saturation (“SpO2”), fractional arterial oxygen saturation (“SpaO2”), or the like. In an embodiment, the monitor advantageously includes a plurality of display modes enabling more parameter data to be displayed than the available physical display real estate.

Stereo pulse oximeter

An improved pulse oximeter provides for simultaneous, noninvasive oxygen status and photoplethysmograph measurements at both single and multiple sites. In particular, this multiple-site, multiple-parameter pulse oximeter, or “stereo pulse oximeter” simultaneously measures both arterial and venous oxygen saturation at any specific site and generates a corresponding plethysmograph waveform. A corresponding computation of arterial minus venous oxygen saturation is particularly advantageous for oxygen therapy management. An active pulse-inducing mechanism having a scattering-limited drive generates a consistent pulsatile venous signal utilized for the venous blood measurements. The stereo pulse oximeter also measures arterial oxygen saturation and plethysmograph shape parameters across multiple sites. A corresponding calculation of delta arterial saturation and comparison of plethysmograph shape parameters between multiple sites is particularly advantageous for the detection and management ...

Signal processing apparatus

The present invention involves a method and an apparatus for analyzing measured signals, including the determination of a measurement of correlation in the measured signals during a calculation of a physiological parameter of a monitored patient. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Method and apparatus for demodulating signals in a pulse oximetry system

A method and an apparatus measure blood oxygenation in a subject. A first signal source applies a first input signal during a first time interval. A second signal source applies a second input signal during a second time interval. A detector detects a first parametric signal responsive to the first input signal passing through a portion of the subject having blood therein. The detector also detects a second parametric signal responsive to the second input signal passing through the portion of the subject. The detector generates a detector output signal responsive to the first and second parametric signals. A signal processor receives the detector output signal and demodulates the detector output signal by applying a first demodulation signal to a signal responsive to the detector output signal to generate a first output signal responsive to the first parametric signal. The signal processor applies a second demodulation signal to the signal responsive to the detector output signal to generate a second output signal responsive to the second parametric signal. The first demodulation signal and the second demodulation signal both include at least a first component having a first frequency and a first amplitude and a second component having a second frequency and a second amplitude. The second frequency is a harmonic of the first frequency. The second amplitude is related to the first amplitude to minimize crosstalk from the first parametric signal to the second output signal and to minimize crosstalk from the second parametric signal to the first output signal.

Signal processing apparatus

The present invention involves a method and an apparatus for analyzing measured signals, including the determination of a measurement of correlation in the measured signals during a calculation of a physiological parameter of a monitored patient. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Multiple wavelength sensor emitters

A physiological sensor has light emitting sources, each activated by addressing at least one row and at least one column of an electrical grid. The light emitting sources are capable of transmitting light of multiple wavelengths and a detector is responsive to the transmitted light after attenuation by body tissue.

Physiological monitor

A patient monitor has multiple sensors adapted to attach to tissue sites of a living subject. The sensors generate sensor signals that are responsive to at least two wavelengths of optical radiation after attenuation by pulsatile blood within the tissue sites.

Plethysmograph pulse recognition processor

A time domain rule-based processor provides recognition of individual pulses in a pulse oximeter-derived waveform.

Pulse oximeter probe-off detector

A processor provides signal quality based limits to a signal strength operating region of a pulse oximeter. These limits are superimposed on the typical gain dependent signal strength limits. If a sensor signal appears physiologically generated, the pulse oximeter is allowed to operate with minimal signal strength, maximizing low perfusion performance. If a sensor signal is potentially due to a signal induced by a dislodged sensor, signal strength requirements are raised. Thus, signal quality limitations enhance probe off detection without significantly impacting low perfusion performance. One signal quality measure used is pulse rate density, which defines the percentage of time physiologically acceptable pulses are occurring. If the detected signal contains a significant percentage of unacceptable pulses, the minimum required signal strength is raised proportionately. Another signal quality measure used in conjunction with pulse rate density is energy ratio, computed as the percentage ...

SIGNAL PROCESSING APPARATUS

The present disclosure describes a method and an apparatus for analyzing measured signals using various processing techniques. In certain embodiments, the measured signals are physiological signals. In certain embodiments, the measurements relate to blood constituent measurements including blood oxygen saturation.

Multiple wavelength sensor emitters

A physiological sensor has light emitting sources, each activated by addressing at least one row and at least one column of an electrical grid. The light emitting sources are capable of transmitting light of multiple wavelengths and a detector is responsive to the transmitted light after attenuation by body tissue.

Signal processing apparatus and method

A method and an apparatus to analyze two measured signals that are modeled as containing desired and undesired portions such as noise, FM and AM modulation. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, a transformation is used to evaluate a ratio of the two measured signals in order to find appropriate coefficients. The measured signals are then fed into a signal scrubber which uses the coefficients to remove the unwanted portions. The signal scrubbing is performed in either the time domain or in the frequency domain. The method and apparatus are particularly advantageous to blood oximetry and pulserate measurements. In another embodiment, an estimate of the pulserate is obtained by applying a set of rules to a spectral transform of the scrubbed signal. In another embodiment, an estimate of the pulserate is obtained by transforming the scrubbed signal from a first spectral domain into a second spectral domain ...

Multiple wavelength sensor equalization

A physiological sensor has intensity compensation introduced along an optical path from emission to detection so as to compensate for unequal tissue attenuation as a function of wavelength. The sensor has emitters configured to transmit optical radiation having multiple wavelengths into a tissue site. At least one detector is capable of receiving the optical radiation after tissue attenuation. An equalization is capable of compensating optical radiation intensity so as to account for differences in tissue attenuation across at least a portion of the multiple wavelengths.

Parameter compensated physiological monitor

A monitor has a primary input from which a spectral characteristic of a tissue site can be derived. The monitor also has a secondary input from which at least one parameter can be determined. A compensation relationship of the spectral characteristic, the parameter and a compensated physiological measurement is determined. A processor is configured to output the compensated physiological measurement in response to the primary input and the secondary input utilizing the compensation relationship.

Stereo pulse oximeter

An improved pulse oximeter provides for simultaneous, noninvasive oxygen status and photoplethysmograph measurements at both single and multiple sites. In particular, this multiple-site, multiple-parameter pulse oximeter, or “stereo pulse oximeter” simultaneously measures both arterial and venous oxygen saturation at any specific site and generates a corresponding plethysmograph waveform. A corresponding computation of arterial minus venous oxygen saturation is particularly advantageous for oxygen therapy management. An active pulse-inducing mechanism having a scattering-limited drive generates a consistent pulsatile venous signal utilized for the venous blood measurements. The stereo pulse oximeter also measures arterial oxygen saturation and plethysmograph shape parameters across multiple sites. A corresponding calculation of delta arterial saturation and comparison of plethysmograph shape parameters between multiple sites is particularly advantageous for the detection and management ...

Power supply rail controller

A power supply rail controller operates on an analog component having a signal input, a power input and a signal output. A voltage controller provides a control output responsive to the signal output. A power supply generates a voltage for the power input, where the voltage is responsive to the control output. The voltage is reduced in magnitude to reduce power dissipation and increased in magnitude to avoid signal distortion.

Signal processing apparatus

The present invention involves method and apparatus for analyzing two measured signals that are modeled as containing primary and secondary portions. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, the present invention involves utilizing a transformation which evaluates a plurality of possible signal coefficients in order to find appropriate coefficients. Alternatively, the present invention involves using statistical functions or Fourier transform and windowing techniques to determine the coefficients relating to two measured signals. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Signal processing apparatus

The present invention involves method and apparatus for analyzing measured signals that are modeled as containing primary and secondary portions. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, the present invention involves utilizing a transformation which evaluates a plurality of possible signal coefficients in order to find appropriate coefficients. Alternatively, the present invention involves using statistical functions or Fourier transform and windowing techniques to determine the coefficients relating to two measured signals. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Physiological parameter tracking system

A physiological parameter tracking system has a reference parameter calculator configured to provide a reference parameter responsive to a physiological signal input. A physiological measurement output is a physiological parameter derived from the physiological signal input during a favorable condition and an estimate of the physiological parameter according to the reference parameter during an unfavorable condition.

Multiple wavelength sensor substrate

A physiological sensor has emitters configured to transmit optical radiation having multiple wavelengths in response to corresponding drive currents. A thermal mass is disposed proximate the emitters so as to stabilize a bulk temperature for the emitters. A temperature sensor is thermally coupled to the thermal mass. The temperature sensor provides a temperature sensor output responsive to the bulk temperature so that the wavelengths are determinable as a function of the drive currents and the bulk temperature.

Physiological parameter confidence measure

Confidence in a physiological parameter is measured from physiological data responsive to the intensity of multiple wavelengths of optical radiation after tissue attenuation. The physiological parameter is estimated based upon the physiological data. Reference data clusters are stored according to known values of the physiological parameter. At least one of the data clusters is selected according to the estimated physiological parameter. The confidence measure is determined from a comparison of the selected data clusters and the physiological data.

Multiple wavelength sensor drivers

A cable is capable of communicating signals between a monitor and a physiological sensor. The monitor is capable of activating individual light emitters of an emitter array arranged in an electrical grid by driving at least one of row drive lines and at least one of column drive lines of the electrical grid. The cable has a first row input, a first column input, a second row input and a second column input. The cable also has a first output which combines the first row input and the first column input and a second output which combines the second row input and the second column input. The inputs are adapted to connect to electrical grid drive lines of a monitor. Further, the outputs are adapted to connect to contacts of a physiological sensor having back-to-back configured LEDs in electrical communication with the contacts.

Physiological monitor

A patient monitor has multiple sensors adapted to attach to tissue sites of a living subject. The sensors generate sensor signals that are responsive to at least two wavelengths of optical radiation after attenuation by pulsatile blood within the tissue sites. Multiple data channels and associated quality parameters are derived from the sensor signals. A processor is configured to operate on the channels according to the quality parameters so as to provide a robust oxygen status measurement.

Noninvasive multi-parameter patient monitor

Embodiments of the present disclosure include a handheld multi-parameter patient monitor capable of determining multiple physiological parameters from the output of a light sensitive detector capable of detecting light attenuated by body tissue. For example, in an embodiment, the monitor is capable of advantageously and accurately displaying one or more of pulse rate, plethysmograph data, perfusion quality, signal confidence, and values of blood constituents in body tissue, including for example, arterial carbon monoxide saturation (HbCO), methemoglobin saturation (HbMet), total hemoglobin (Hbt), arterial oxygen saturation (SpO2), fractional arterial oxygen saturation (SpaO2), or the like. In an embodiment, the monitor advantageously includes a plurality of display modes enabling more parameter data to be displayed than the available physical display real estate.

Parameter compensated physiological monitor

A monitor has an optical input from which a spectral characteristic can be derived. The monitor also has a non-optical input from which a parameter can be determined. A compensation relationship is determined for the spectral characteristic based on the parameter. A physiological measurement is determined based on the spectral characteristic and the compensation relationship.

Multi-wavelength physiological monitor

A physiological monitor for determining blood oxygen saturation of a medical patient includes a sensor, a signal processor and a display. The sensor includes at least three light emitting diodes. Each light emitting diode is adapted to emit light of a different wavelength. The sensor also includes a detector, where the detector is adapted to receive light from the three light emitting diodes after being attenuated by tissue. The detector generates an output signal based at least in part upon the received light. The signal processor determines blood oxygen saturation based at least upon the output signal, and the display provides an indication of the blood oxygen saturation.

Multiple wavelength sensor emitters

A physiological sensor has light emitting sources, each activated by addressing at least one row and at least one column of an electrical grid. The light emitting sources are capable of transmitting light of multiple wavelengths and a detector is responsive to the transmitted light after attenuation by body tissue.

Signal processing apparatus

A signal processor which acquires a first signal, including a first primary signal portion and a first secondary signal portion, and a second signal, including a second primary signal portion and a second secondary signal portion, wherein the first and second primary signal portions are correlated. The signals may be acquired by propagating energy through a medium and measuring an attenuated signal after transmission or reflection. Alternatively, the signals may be acquired by measuring energy generated by the medium. A processor of the present invention generates a primary or secondary reference signal which is a combination, respectively, of only the primary or secondary signal portions. The secondary reference signal is then used to remove the secondary portion of each of the first and second measured signals via a correlation canceler, such as an adaptive noise canceler, preferably of the joint process estimator type. The primary reference signal is used to remove the primary portion ...

Multiple wavelength sensor substrate

A physiological sensor has emitters configured to transmit optical radiation having multiple wavelengths in response to corresponding drive currents. A thermal mass is disposed proximate the emitters so as to stabilize a bulk temperature for the emitters. A temperature sensor is thermally coupled to the thermal mass. The temperature sensor provides a temperature sensor output responsive to the bulk temperature so that the wavelengths are determinable as a function of the drive currents and the bulk temperature.

METHOD AND APPARATUS FOR DEMODULATING SIGNALS IN A PULSE OXIMETRY SYSTEM

A method and an apparatus measure blood oxygenation in a subject. A light source is activated to cause a first emission at a first wavelength and a second emission at a second wavelength. A detector detects a composite signal indicative of an attenuation of the first and second wavelengths by tissue of a patient. The composite signal is demodulated into a first intensity signal and a second intensity signal. Blood oxygenation in the subject is determined from the first and second intensity signals. In one embodiment, demodulation is based at least in part on a period when at least one of the wavelengths is not activated. In one embodiment, a modulation of the first and second wavelengths is determined in order to avoid frequencies of ambient noise. In one embodiment, the composite signal's sampling rate is reduced before and/or after demodulation.

Signal processing apparatus

The present invention involves a method and an apparatus for analyzing measured signals, including the determination of a measurement of correlation in the measured signals during a calculation of a physiological parameter of a monitored patient. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Signal processing apparatus

The present invention involves method and apparatus for analyzing two measured signals that are modeled as containing primary and secondary portions. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, the present invention involves utilizing a transformation which evaluates a plurality of possible signal coefficients in order to find appropriate coefficients. Alternatively, the present invention involves using statistical functions or Fourier transform and windowing techniques to determine the coefficients relating to two measured signals. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Noninvasive multi-parameter patient monitor

Embodiments of the present disclosure include a handheld multi-parameter patient monitor capable of determining multiple physiological parameters from the output of a light sensitive detector capable of detecting light attenuated by body tissue. For example, in an embodiment, the monitor is capable of advantageously and accurately displaying one or more of pulse rate, plethysmograph data, perfusion quality, signal confidence, and values of blood constituents in body tissue, including for example, arterial carbon monoxide saturation (“HbCO”), methemoglobin saturation (“HbMet”), total hemoglobin (“Hbt”), arterial oxygen saturation (“SpO2”), fractional arterial oxygen saturation (“SpaO2”), or the like. In an embodiment, the monitor advantageously includes a plurality of display modes enabling more parameter data to be displayed than the available physical display real estate.

Plethysmograph pulse recognition processor

An intelligent, rule-based processor provides recognition of individual pulses in a pulse oximeter-derived photo-plethysmograph waveform. Pulse recognition occurs in two stages. The first stage identifies candidate pulses in the plethysmograph waveform. The candidate pulse stage identifies points in the waveform representing peaks and valleys corresponding to an idealized triangular wave model of the waveform pulses. At this stage, waveform features that do not correspond to this model are removed, including the characteristic dicrotic notch. The second stage applies a plethysmograph model to the candidate pulses and decides which pulses satisfies this model. This is done by first calculating certain pulse features and then applying different checks to identify physiologically acceptable features. Various statistics can then be derived from the resulting pulse information, including the period and signal strength of each pulse and pulse density, which is the ratio of the analyzed waveform ...

Robust alarm system

A robust alarm system has an alarm controller adapted to input an alarm trigger and to generate at least one alarm drive signal in response. Alarm subsystems input the alarm drive signal and activate one or more of multiple alarms accordingly. A subsystem function signal provides feedback to the alarm controller as to alarm subsystem integrity. A malfunction indicator is output from the alarm controller in response to a failure within the alarm subsystems.

Signal processing apparatus and method

A signal processor which acquires a first signal, including a first desired signal portion and a first undesired signal portion, and a second signal, including a second desired signal portion and a second undesired signal portion, wherein the first and second desired signal portions are correlated. The signals may be acquired by propagating energy through a medium and measuring an attenuated signal after transmission or reflection. Alternatively, the signals may be acquired by measuring energy generated by the medium. A processor of the present invention generates a noise reference signal that is a combination of the undesired signal portions and is correlated to both the first and second undesired signal portions. The noise reference signal is then used to remove the undesired portion of each of the first and second measured signals. The processor of the present invention may be employed in physiological monitors wherein the known properties of energy attenuation through a medium are used ...

Plethysmograph pulse recognition processor

A time domain rule-based processor provides recognition of individual pulses in a pulse oximeter-derived photo-plethysmograph waveform.

Multiple wavelength sensor drivers

A physiological sensor includes an electrical grid to activate one or more light emitters by addressing at least one row conductor and at least one column conductor. Each light emitter includes a positive terminal and a negative terminal. The physiological sensor includes a first light emitter and a second light emitter. A first contact is communicatively coupled with the positive terminal of the first light emitter, the negative terminal of the second light emitter, a first row conductor, and a first column conductor. A second contact is communicatively coupled with the negative terminal of the first light emitter, the positive terminal of the second light emitter, a second row conductor, and a second column conductor. The first light emitter is activated by addressing the first row conductor and the second column conductor. The second light emitter is activated by addressing the second row conductor and the first column conductor.

RESPIRATION PROCESSOR

Respiratory rate can be calculated from an acoustic input signal using time domain and frequency domain techniques. Confidence in the calculated respiratory rate can also be calculated using time domain and frequency domain techniques. Overall respiratory rate and confidence values can be obtained from the time and frequency domain calculations. The overall respiratory rate and confidence values can be output for presentation to a clinician. 120-. (canceled)21. A system for determining a respiration rate of a patient using an acoustic signal received from an acoustic sensor adapted to monitor the patient , the system comprising:an input configured to receive the acoustic signal from the acoustic sensor; and generate a time domain envelope signal from the acoustic signal,', 'tag a plurality of local extremum in the time domain envelope signal as potentially corresponding to an inspiration or an expiration of the patient,', 'determine to reject at least one local extremum of the plurality of local extremum as not corresponding to the inspiration or the expiration,', 'determine a respiratory rate from the plurality of local extremum without using the at least one local extremum that was determined to be rejected, and', 'output the respiratory rate., 'one or more hardware processors configured to22. The system of claim 21 , wherein the one or more hardware processors are configured to determine to reject a first local extremum of the plurality of local extremum according to a time difference between the first local extremum and a second local extremum of the plurality of local extremum claim 21 , the at least one local extremum that was determined to be rejected comprising the first local extremum.23. The system of claim 22 , wherein the first local extremum and the second local extremum are consecutively-occurring local extremum in the time domain envelope signal.24. The system of claim 22 , wherein the one or more hardware processors are configured to determine to ...

NONINVASIVE MULTI-PARAMETER PATIENT MONITOR

Embodiments of the present disclosure include a handheld multi-parameter patient monitor capable of determining multiple physiological parameters from the output of a light sensitive detector capable of detecting light attenuated by body tissue. For example, in an embodiment, the monitor is capable of advantageously and accurately displaying one or more of pulse rate, plethysmograph data, perfusion quality, signal confidence, and values of blood constituents in body tissue, including for example, arterial carbon monoxide saturation (“HbCO”), methemoglobin saturation (“HbMet”), total hemoglobin (“Hbt”), arterial oxygen saturation (“SpO”), fractional arterial oxygen saturation (“SpaO”), or the like. The monitor can determine which a plurality of light emitting sources and which of a plurality of parameters to measure based on the signal quality and resources available. 1. A method of determining which of a plurality of physiological measurements to measure based on the signal quality of the signal , the method comprising:using a sensor configured to measure at least two different physiological measurements to obtain a signal from a light sensitive detector, the sensor including at least three different light emitters emitting at least three different wavelengths of light through tissue of a living patient and detecting the light after attenuation of the tissue;determining a signal quality of the signal;determining which of the at least two different physiological measurements are capable of being measured based on the signal quality determination; andactivating only enough of the at least three different light emitters necessary to obtain the measurements capable of being measured.2. The method of claim 1 , wherein if the signal quality is high claim 1 , all of the at least three different emitters are activated.3. The method of claim 1 , wherein if the signal quality is low claim 1 , only two of the at least three different emitters are activated.4. The method of ...

Signal processing apparatus

The present invention involves a method and an apparatus for analyzing measured signals, including the determination of a measurement of correlation in the measured signals during a calculation of a physiological parameter of a monitored patient. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Pulse and active pulse spectraphotometry

A pulse and active pulse spectraphotometry system comprises a light source adapted to illuminate a tissue site with optical radiation having a plurality of wavelengths selected from at least one of a primary band of about 1620 nm to about 1730 nm and a secondary band of about 1000 nm to about 1380 nm.

Signal processing apparatus

The present invention involves a method and an apparatus for analyzing measured signals, including the determination of a measurement of correlation in the measured signals during a calculation of a physiological parameter of a monitored patient. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Pulse and active pulse spectraphotometry

A pulse and active pulse spectraphotometry system comprises a light source adapted to illuminate a tissue site with optical radiation having a plurality of wavelengths selected from at least one of a primary band and a secondary band. The tissue site has a modulated blood volume resulting from the pulsatile nature of arterial blood or from an induced pulse. A detector is configured to receive the optical radiation attenuated by the tissue site and to generate a detector output responsive to absorption of the optical radiation within the tissue site. A normalizer operating on the detector output generates a plurality of normalized plethysmographs corresponding to the plurality of wavelengths. Further, a processor is configured to calculate a ratio of fractional volumes of analytes in the blood volume based upon the normalized plethysmographs.

Optical spectroscopy pathlength measurement system

A physiological monitor utilizes Faraday rotation measurements to estimate mean photon pathlengths through tissue. These pathlength estimates, along with corresponding optical spectroscopy measurements allow the noninvasive monitoring of blood constituent concentrations. The technique is particularly applicable to noninvasive blood glucose measurements. The physiological monitor has a polarized light source for illuminating tissue and a magnetic field generator which creates a magnetic field within the tissue during illumination. The magnetic field imparts a Faraday rotation in the plane of polarization of the incident light beam as it propagates through the tissue and emerges as a transmitted light beam. A polarimeter is used to measure the rotation of the transmitted light. A signal processor then computes an estimate of the mean pathlength from the polarimeter output. The polarized light source has a multiple wavelength optical emitter and, in conjunction with the polarimeter detector ...

Signal processing apparatus

The present disclosure describes a method and an apparatus for analyzing measured signals using various processing techniques. In certain embodiments, the measured signals are physiological signals. In certain embodiments, the measurements relate to blood constituent measurements including blood oxygen saturation.

Multiple wavelength sensor emitters

A physiological sensor has light emitting sources, each activated by addressing at least one row and at least one column of an electrical grid. The light emitting sources are capable of transmitting light of multiple wavelengths and a detector is responsive to the transmitted light after attenuation by body tissue.

Manual and automatic probe calibration

The method and apparatus of the present invention provides a system wherein light-emitting diodes (LEDs) can be tuned within a given range by selecting their operating drive current in order to obtain a precise wavelength. The present invention further provides a manner in which to calibrate and utilize an LED probe, such that the shift in wavelength for a known change in drive current is a known quantity. In general, the principle of wavelength shift for current drive changes for LEDs is utilized in order to allow better calibration and added flexibility in the use of LED sensors, particularly in applications when the precise wavelength is needed in order to obtain accurate measurements. The present invention also provides a system in which it is not necessary to know precise wavelengths of LEDs where precise wavelengths were needed in the past. Finally, the present invention provides a method and apparatus for determining the operating wavelength of a light emitting element such as a ...

Systems and methods for acquiring calibration data usable in a pause oximeter

The present disclosure includes a pulse oximeter attachment having an accessible memory. In one embodiment, the pulse oximeter attachment stores calibration data, such as, for example, calibration data associated with a type of a sensor, a calibration curve, or the like. The calibration data is used to calculate physiological parameters of pulsing blood.

Physiological monitor

A patient monitor has multiple sensors adapted to attach to tissue sites of a living subject. The sensors generate sensor signals that are responsive to at least two wavelengths of optical radiation after attenuation by pulsatile blood within the tissue sites. A patient monitor uses the signals to determine if there is a heart abnormality.

Multi-wavelength physiological monitor

A physiological monitor for determining blood oxygen saturation of a medical patient includes a sensor, a signal processor and a display. The sensor includes at least three light emitting diodes. Each light emitting diode is adapted to emit light of a different wavelength. The sensor also includes a detector, where the detector is adapted to receive light from the three light emitting diodes after being attenuated by tissue. The detector generates an output signal based at least in part upon the received light. The signal processor determines blood oxygen saturation based at least upon the output signal, and the display provides an indication of the blood oxygen saturation.

Systems and methods for determining blood oxygen saturation values using complex number encoding

The disclosure includes pulse oximetry systems and methods for determining point-by-point saturation values by encoding photoplethysmographs in the complex domain and processing the complex signals. The systems filter motion artifacts and other noise using a variety of techniques, including statistical analysis such as correlation, or phase filtering.

SIGNAL PROCESSING APPARATUS

The present disclosure describes a method and an apparatus for analyzing measured signals using various processing techniques. In certain embodiments, the measured signals are physiological signals. In certain embodiments, the measurements relate to blood constituent measurements including blood oxygen saturation.

Physiological monitor

A patient monitor has multiple sensors adapted to attach to tissue sites of a living subject. The sensors generate sensor signals that are responsive to at least two wavelengths of optical radiation after attenuation by pulsatile blood within the tissue sites. A patient monitor uses the plurality of signals to reduce the effects of noise.

LOW-NOISE OPTICAL PROBES FOR REDUCING AMBIENT NOISE

An optical probe, which is particularly suited to reduce noise in measurements taken on an easily compressible material, such as a finger, a toe, a forehead, an earlobe, or a lip, measures characteristics of the material. A neonatal and adult disposable embodiment of the probe include adhesive coated surfaces to securely affix the probe onto the patient. In addition, the surface of the probe is specially constructed to reduce the effect of ambient noise.

HEMOGLOBIN MONITOR

A patient monitor system is configured to measure and display a hemoglobin concentration measurement to assist caregivers in providing care or treatment and/or to automatically control a fluid, blood, medicine, or dialysis administration system. The patient monitor can analyze the displayed hemoglobin concentration measurement and provide alarms and feedback to assist caregivers. Additional measurement can be combined with the hemoglobin concentration measurement to provide combined displays helpful to caregivers, such as, for example, a plethysmograph variability index v. SpHb display.

MULTIPLE WAVELENGTH SENSOR SUBSTRATE

A physiological sensor has emitters configured to transmit optical radiation having multiple wavelengths in response to corresponding drive currents. A thermal mass is disposed proximate the emitters so as to stabilize a bulk temperature for the emitters. A temperature sensor is thermally coupled to the thermal mass. The temperature sensor provides a temperature sensor output responsive to the bulk temperature so that the wavelengths are determinable as a function of the drive currents and the bulk temperature.

MULTIPLE WAVELENGTH SENSOR DRIVERS

A physiological sensor includes an electrical grid to activate one or more light emitters by addressing at least one row conductor and at least one column conductor. Each light emitter includes a positive terminal and a negative terminal. The physiological sensor includes a first light emitter and a second light emitter. A first contact is communicatively coupled with the positive terminal of the first light emitter, the negative terminal of the second light emitter, a first row conductor, and a first column conductor. A second contact is communicatively coupled with the negative terminal of the first light emitter, the positive terminal of the second light emitter, a second row conductor, and a second column conductor. The first light emitter is activated by addressing the first row conductor and the second column conductor. The second light emitter is activated by addressing the second row conductor and the first column conductor.

Low-noise optical probes for reducing ambient noise

An optical probe, which is particularly suited to reduce noise in measurements taken on an easily compressible material, such as a finger, a toe, a forehead, an earlobe, or a lip, measures characteristics of the material. A neonatal and adult disposable embodiment of the probe include adhesive coated surfaces to securely affix the probe onto the patient. In addition, the surface of the probe is specially constructed to reduce the effect of ambient noise.

Dual-mode pulse oximeter

A portable stand alone patient monitor is dockable with a docking station attached to a patient bed. The portable monitor is configured to operate in a stand alone mode and a docked mode. The docking station can include a second local monitor.

Multiple wavelength sensor emitters

A physiological sensor has light emitting sources, each activated by addressing at least one row and at least one column of an electrical grid. The light emitting sources are capable of transmitting light of multiple wavelengths and a detector is responsive to the transmitted light after attenuation by body tissue.

MULTIPLE WAVELENGTH SENSOR EMITTERS

A physiological sensor has light emitting sources, each activated by addressing at least one row and at least one column of an electrical grid. The light emitting sources are capable of transmitting light of multiple wavelengths and a detector is responsive to the transmitted light after attenuation by body tissue. 1. A physiological sensor comprising:a plurality of light emitting sources, each light emitting source activated by addressing at least one of a plurality of rows and at least one of a plurality of columns of an electrical grid, the light emitting sources capable of transmitting light of a plurality of wavelengths; anda detector responsive to the transmitted light after attenuation by body tissue.2. The physiological sensor according to wherein multiple ones of the light emitting sources are capable of transmitting light of the same wavelength claim 1 , the multiple ones simultaneously activated by addressing one of the rows.3. The physiological sensor according to wherein:the light emitting sources are LEDs, andeach of the LEDs have an anode in common with one of the rows and a cathode in common with one of the columns so that driving one of the rows and one of the columns activates a unique one of the LEDs.4. The physiological sensor according to further comprising:a plurality of row drivers in communication with the rows; anda plurality of column drivers in communication with the columns,wherein a selected row driver sources current to a corresponding row and selected column driver sinks current from a corresponding column so as to activate an addressed one of the LEDs.5. The physiological sensor according to wherein deselected ones of the row drivers pull corresponding rows to a low voltage and deselected ones of the column drivers pull corresponding columns to a high voltage so as to substantially block parasitic current from unaddressed ones of the LEDs.6. The physiological sensor according to wherein the electrical grid comprises at least three ...

PHYSIOLOGICAL PARAMETER CONFIDENCE MEASURE

Confidence in a physiological parameter is measured from physiological data responsive to the intensity of multiple wavelengths of optical radiation after tissue attenuation. The physiological parameter is estimated based upon the physiological data. Reference data clusters are stored according to known values of the physiological parameter. At least one of the data clusters is selected according to the estimated physiological parameter. The confidence measure is determined from a comparison of the selected data clusters and the physiological data.

Multiple wavelength sensor emitters

A physiological sensor is adapted to removably attach an emitter assembly and a detector assembly to a fingertip. The emitter assembly is adapted to transmit optical radiation having multiple wavelengths into fingertip tissue. The detector assembly is adapted to receive the optical radiation after attenuation by the fingertip tissue. The sensor has a first shell and a second shell hinged to the first shell. A spring is disposed between the shells and urges the shells together. An emitter pad is fixedly attached to the first shell and configured to retain the emitter assembly. A detector pad is fixedly attached to the second shell and configured to retain the detector assembly. A detector aperture is defined within the detector pad and adapted to pass optical radiation to the detector assembly. A contour is defined along the detector pad and generally shaped to conform to a fingertip positioned over the detector aperture.

NONINVASIVE MULTI-PARAMETER PATIENT MONITOR

Embodiments of the present disclosure include a handheld multi-parameter patient monitor capable of determining multiple physiological parameters from the output of a light sensitive detector capable of detecting light attenuated by body tissue. For example, in an embodiment, the monitor is capable of advantageously and accurately displaying one or more of pulse rate, plethysmograph data, perfusion quality, signal confidence, and values of blood constituents in body tissue, including for example, arterial carbon monoxide saturation, methemoglobin saturation, total hemoglobin, arterial oxygen saturation, fractional arterial oxygen saturation, or the like. In an embodiment, the monitor advantageously includes a plurality of display modes enabling more parameter data to be displayed than the available physical display real estate. In an embodiment, the monitor advantageously includes a mode indicator to inform a user as to which parameter measurement would be displayed in one or more display ...

Pulse oximetry sensor

A pulse oximetry sensor has an emitter adapted to transmit optical radiation of at least two wavelengths into a tissue site and a detector adapted to receive optical radiation from the emitter after tissue site absorption. A tape assembly is adapted to attach the emitter and detector to the tissue site. A flexible housing is disposed around and optically shields the detector.

Multiple wavelength sensor substrate

A physiological sensor has emitters configured to transmit optical radiation having multiple wavelengths in response to corresponding drive currents. A thermal mass is disposed proximate the emitters so as to stabilize a bulk temperature for the emitters. A temperature sensor is thermally coupled to the thermal mass. The temperature sensor provides a temperature sensor output responsive to the bulk temperature so that the wavelengths are determinable as a function of the drive currents and the bulk temperature.

LOW-NOISE OPTICAL PROBES FOR REDUCING AMBIENT NOISE

An optical probe, which is particularly suited to reduce noise in measurements taken on an easily compressible material, such as a finger, a toe, a forehead, an earlobe, or a lip, measures characteristics of the material. A neonatal and adult disposable embodiment of the probe include adhesive coated surfaces to securely affix the probe onto the patient. In addition, the surface of the probe is specially constructed to reduce the effect of ambient noise.

SIGNAL PROCESSING APPARATUS

The present disclosure describes a method and an apparatus for analyzing measured signals using various processing techniques. In certain embodiments, the measured signals are physiological signals. In certain embodiments, the measurements relate to blood constituent measurements including blood oxygen saturation.

Low-noise optical probes for reducing ambient noise

An optical probe, which is particularly suited to reduce noise in measurements taken on an easily compressible material, such as a finger, a toe, a forehead, an earlobe, or a lip, measures characteristics of the material. A neonatal and adult disposable embodiment of the probe include adhesive coated surfaces to securely affix the probe onto the patient. In addition, the surface of the probe is specially constructed to reduce the effect of ambient noise.

Noninvasive multi-parameter patient monitor

Embodiments of the present disclosure include a handheld multi-parameter patient monitor capable of determining multiple physiological parameters from the output of a light sensitive detector capable of detecting light attenuated by body tissue. For example, in an embodiment, the monitor is capable of advantageously and accurately displaying one or more of pulse rate, plethysmograph data, perfusion quality, signal confidence, and values of blood constituents in body tissue, including for example, arterial carbon monoxide saturation (HbCO), methemoglobin saturation (HbMet), total hemoglobin (Hbt), arterial oxygen saturation (SpO2), fractional arterial oxygen saturation (SpaO2), or the like. In an embodiment, the monitor advantageously includes a plurality of display modes enabling more parameter data to be displayed than the available physical display real estate.

Multi-wavelength physiological monitor

A physiological monitor for determining blood oxygen saturation of a medical patient includes a sensor, a signal processor and a display. The sensor includes at least three light emitting diodes. Each light emitting diode is adapted to emit light of a different wavelength. The sensor also includes a detector, where the detector is adapted to receive light from the three light emitting diodes after being attenuated by tissue. The detector generates an output signal based at least in part upon the received light. The signal processor determines blood oxygen saturation based at least upon the output signal, and the display provides an indication of the blood oxygen saturation.

Low-noise optical probes for reducing ambient noise

An optical probe, which is particularly suited to reduce noise in measurements taken on an easily compressible material, such as a finger, a toe, a forehead, an earlobe, or a lip, measures characteristics of the material. A neonatal and adult disposable embodiment of the probe include adhesive coated surfaces to securely affix the probe onto the patient. In addition, the surface of the probe is specially constructed to reduce the effect of ambient noise.

Low-noise optical probes for reducing light piping

An optical probe, which is particularly suited to reduce noise in measurements taken on an easily compressible material, such as a finger, a toe, a forehead, an earlobe, or a lip, measures characteristics of the material. A neonatal and adult disposable embodiment of the probe include adhesive coated surfaces to securely affix the probe onto the patient. In addition, the surface of the probe is specially constructed to minimize light piping effects. Furthermore, a flex circuit acts as a spring to absorb shock which may misalign the emitter and detector. One embodiment of the adult probe includes a cushioning pocket formed for a fingertip to align the probe and to absorb motion of the probe due to contact. The neonatal probe is formed with a unique V-configuration which provides multiple advantages.

MULTIPLE WAVELENGTH SENSOR EMITTERS

A physiological sensor is adapted to removably attach an emitter assembly and a detector assembly to a fingertip. The emitter assembly is adapted to transmit optical radiation having multiple wavelengths into fingertip tissue. The detector assembly is adapted to receive the optical radiation after attenuation by the fingertip tissue. The sensor has a first shell and a second shell hinged to the first shell. A spring is disposed between the shells and urges the shells together. An emitter pad is fixedly attached to the first shell and configured to retain the emitter assembly. A detector pad is fixedly attached to the second shell and configured to retain the detector assembly. A detector aperture is defined within the detector pad and adapted to pass optical radiation to the detector assembly. A contour is defined along the detector pad and generally shaped to conform to a fingertip positioned over the detector aperture.

Pulse oximeter probe-off detector

An intelligent, rule-based processor provides signal quality based limits to the signal strength operating region of a pulse oximeter. These limits are superimposed on the typical gain dependent signal strength limits. If a sensor signal appears physiologically generated, the pulse oximeter is allowed to operate with minimal signal strength, maximizing low perfusion performance. If a sensor signal is potentially due to a signal induced by a dislodged sensor, signal strength requirements are raised. Thus, signal quality limitations enhance probe off detection without significantly impacting low perfusion performance. One signal quality measure used is pulse rate density, which defines the percentage of time physiologically acceptable pulses are occurring. If the detected signal contains a significant percentage of unacceptable pulses, the minimum required signal strength is raised proportionately. Another signal quality measure used in conjunction with pulse rate density is energy ratio, ...

Physiological parameter confidence measure

Confidence in a physiological parameter is measured from physiological data responsive to the intensity of multiple wavelengths of optical radiation after tissue attenuation. The physiological parameter is estimated based upon the physiological data. Reference data clusters are stored according to known values of the physiological parameter. At least one of the data clusters is selected according to the estimated physiological parameter. The confidence measure is determined from a comparison of the selected data clusters and the physiological data.

Signal processing apparatus

The present invention involves method and apparatus for analyzing measured signals that are modeled as containing primary and secondary portions. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, the present invention involves utilizing a transformation which evaluates a plurality of possible signal coefficients in order to find appropriate coefficients. Alternatively, the present invention involves using statistical functions or Fourier transform and windowing techniques to determine the coefficients relating to two measured signals. Use of this invention is described in particular detail with respect to blood oximetry measurements.

RESPIRATION PROCESSOR

Respiratory rate can be calculated from an acoustic input signal using time domain and frequency domain techniques. Confidence in the calculated respiratory rate can also be calculated using time domain and frequency domain techniques. Overall respiratory rate and confidence values can be obtained from the time and frequency domain calculations. The overall respiratory rate and confidence values can be output for presentation to a clinician. 120-. (canceled)21. A system for monitoring respiration of a patient using a signal received from a physiological sensor coupled with the patient , the system comprising:a signal filter configured to receive an acoustic signal from an acoustic sensor coupled to a patient and filter the acoustic signal to generate a filtered output signal;a high gain stage configured to generate a first amplified output signal from the filtered output signal by amplifying the filtered output signal with a first gain level;a low gain stage configured to generate a second amplified output signal from the filtered output signal by amplifying the filtered output signal with a second gain level lower than the first gain level; and responsive to a magnitude of the first amplified output signal, select one of the first amplified output signal and the second amplified output signal to be a selected signal for further processing,', 'determine first respiratory rates from a first domain representation of the selected signal and second respiratory rates from a second domain representation of the selected signal, the first domain representation being different from the second domain representation,', 'assign first confidence values to the first respiratory rates using one or more of (i) a calculation of a spectral density of energy in the first domain representation, (ii) a calculation of a harmonic energy in the first domain representation, (iii) a comparison of local maximums in the first domain representation and one or more magnitude thresholds, and (iv) ...

Manual and automatic probe calibration

Embodiments of the present disclosure include an optical probe capable of communicating identification information to a patient monitor in addition to signals indicative of intensities of light after attenuation by body tissue. The identification information may indicate operating wavelengths of light sources, indicate a type of probe, such as, for example, that the probe is an adult probe, a pediatric probe, a neonatal probe, a disposable probe, a reusable probe, or the like. The information could also be utilized for security purposes, such as, for example, to ensure that the probe is configured properly for the oximeter, to indicate that the probe is from an authorized supplier, or the like. In one preferred embodiment, coding resistors could be provided across the light sources to allow additional information about the probe to be coded without added leads. However, any device could be used without it being used in parallel.

Stereo pulse oximeter

An improved pulse oximeter provides for simultaneous, noninvasive oxygen status and photoplethysmograph measurements at both single and multiple sites. In particular, this multiple-site, multiple-parameter pulse oximeter, or “stereo pulse oximeter” simultaneously measures both arterial and venous oxygen saturation at any specific site and generates a corresponding plethysmograph waveform. A corresponding computation of arterial minus venous oxygen saturation is particularly advantageous for oxygen therapy management. An active pulse-inducing mechanism having a scattering-limited drive generates a consistent pulsatile venous signal utilized for the venous blood measurements. The stereo pulse oximeter also measures arterial oxygen saturation and plethysmograph shape parameters across multiple sites. A corresponding calculation of delta arterial saturation and comparison of plethysmograph shape parameters between multiple sites is particularly advantageous for the detection and management ...

PHYSIOLOGICAL PARAMETER TRACKING SYSTEM

A physiological parameter tracking system has a reference parameter calculator configured to provide a reference parameter responsive to a physiological signal input. A physiological measurement output is a physiological parameter derived from the physiological signal input during a favorable condition and an estimate of the physiological parameter according to the reference parameter during an unfavorable condition.

Physiological parameter tracking system

A physiological parameter tracking system generates a reference parameter and a slowly varying parameter responsive to a physiological signal input. The slowly varying parameter is generated according to an update command. A physiological measurement output is provided that is responsive to a tracking function of the reference parameter and the slowly varying parameter.

Optical spectroscopy pathlength measurement system

A physiological monitor utilizes rotation measurements to estimate mean photon pathlengths through tissue. These pathlength estimates, along with corresponding optical spectroscopy measurements allow the noninvasive monitoring of blood constituent concentrations. The technique is particularly applicable to noninvasive blood glucose measurements. The physiological monitor has a polarized light source for illuminating tissue and a magnetic field generator which creates a magnetic field within the tissue during illumination. The magnetic field imparts a rotation in the plane of polarization of the incident light beam as it propagates through the tissue and emerges as a transmitted light beam. A polarimeter is used to measure the rotation of the transmitted light. A signal processor then computes an estimate of the mean pathlength from the polarimeter output. The polarized light source has a multiple wavelength optical emitter and, in conjunction with the polarimeter detector, also functions ...

Physiological parameter tracking system

A physiological parameter tracking system generates a reference parameter and a slowly varying parameter responsive to a physiological signal input. The slowly varying parameter is generated according to an update command. A physiological measurement output is provided that is responsive to a tracking function of the reference parameter and the slowly varying parameter.

SIGNAL PROCESSING APPARATUS

The present disclosure describes a method and an apparatus for analyzing measured signals using various processing techniques. In certain embodiments, the measured signals are physiological signals. In certain embodiments, the measurements relate to blood constituent measurements including blood oxygen saturation.

Signal processing apparatus and method

A method and an apparatus to analyze two measured signals that are modeled as containing desired and undesired portions such as noise, FM and AM modulation. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, a transformation is used to evaluate a ratio of the two measured signals in order to find appropriate coefficients. The measured signals are then fed into a signal scrubber which uses the coefficients to remove the unwanted portions. The signal scrubbing is performed in either the time domain or in the frequency domain. The method and apparatus are particularly advantageous to blood oximetry and pulserate measurements. In another embodiment, an estimate of the pulserate is obtained by applying a set of rules to a spectral transform of the scrubbed signal. In another embodiment, an estimate of the pulserate is obtained by transforming the scrubbed signal from a first spectral domain into a second spectral domain ...

Optical spectroscopy pathlength measurement system

A physiological monitor utilizes Faraday rotation measurements to estimate mean photon pathlengths through tissue. These pathlength estimates, along with corresponding optical spectroscopy measurements allow the noninvasive monitoring of blood constituent concentrations. The technique is particularly applicable to noninvasive blood glucose measurements. The physiological monitor has a polarized light source for illuminating tissue and a magnetic field generator which creates a magnetic field within the tissue during illumination. The magnetic field imparts a Faraday rotation in the plane of polarization of the incident light beam as it propagates through the tissue and emerges as a transmitted light beam. A polarimeter is used to measure the rotation of the transmitted light. A signal processor then computes an estimate of the mean pathlength from the polarimeter output. The polarized light source has a multiple wavelength optical emitter and, in conjunction with the polarimeter detector ...

Multiple wavelength sensor drivers

A cable is capable of communicating signals between a monitor and a physiological sensor. The monitor is capable of activating individual light emitters of an emitter array arranged in an electrical grid by driving at least one of row drive lines and at least one of column drive lines of the electrical grid. The cable has a first row input, a first column input, a second row input and a second column input. The cable also has a first output which combines the first row input and the first column input and a second output which combines the second row input and the second column input. The inputs are adapted to connect to electrical grid drive lines of a monitor. Further, the outputs are adapted to connect to contacts of a physiological sensor having back-to-back configured LEDs in electrical communication with the contacts.

Signal processing apparatus

The present invention involves method and apparatus for analyzing two measured signals that are modeled as containing primary and secondary portions. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, the present invention involves utilizing a transformation which evaluates a plurality of possible signal coefficients in order to find appropriate coefficients. Alternatively, the present invention involves using statistical functions or Fourier transform and windowing techniques to determine the coefficients relating to two measured signals. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Signal processing apparatus and method

A signal processor which acquires a first signal, including a first desired signal portion and a first undesired signal portion, and a second signal, including a second desired signal portion and a second undesired signal portion, wherein the first and second desired signal portions are correlated. The signals may be acquired by propagating energy through a medium and measuring an attenuated signal after transmission or reflection. Alternatively, the signals may be acquired by measuring energy generated by the medium. A processor of the present invention generates a noise reference signal that is a combination of the undesired signal portions and is correlated to both the first and second undesired signal portions. The noise reference signal is then used to remove the undesired portion of each of the first and second measured signals. The processor of the present invention may be employed in physiological monitors wherein the known properties of energy attenuation through a medium are used ...

MULTIPLE WAVELENGTH SENSOR DRIVERS

A physiological sensor has light sources arranged in one or more rows and one or more columns. Each light source is activated by addressing at least one row and at least one column. The light sources are capable of transmitting light of multiple wavelengths and a detector is responsive to the transmitted light after attenuation by body tissue. 1. A physiological sensor comprising:a plurality of light emitters comprising at least a first light emitter and a second light emitter;an electrical grid configured to activate one or more light emitters of the plurality of light emitters by addressing at least one row conductor and at least one column conductor, wherein each of the one or more light emitters comprises a first terminal and a second terminal;a first contact communicatively coupled with the first terminal of the first light emitter, the second terminal of the second light emitter, a first row conductor, and a first column conductor; anda second contact communicatively coupled with the second terminal of the first light emitter, the first terminal of the second light emitter, a second row conductor, and a second column conductor.2. A physiological sensor comprising:a plurality of light sources arranged in one or more rows and one or more columns, the plurality of light sources comprising at least a first light source and a second light source, wherein one or more light sources of the plurality of light sources are activated by addressing at least one row conductor and at least one column conductor, wherein each of the one or more light sources comprises a first contact and a second contact;a first electrical node communicatively coupled with the first contact of the first light source, the second contact of the second light source, a first row conductor, and a first column conductor; anda second electrical node communicatively coupled with the second contact of the first light source, the first contact of the second light source, a second row conductor, and a ...

Low-noise optical probes

An optical probe, which is particularly suited to reduce noise in measurements taken on an easily compressible material, such as a finger, a toe, a forehead, an earlobe, or a lip, measures characteristics of the material. A neonatal and adult disposable embodiment of the probe include adhesive coated surfaces to securely affix the probe onto the patient. In addition, the surface of the probe is specially constructed to minimize light piping effects. Furthermore, a flex circuit acts as a spring to absorb shock which may misalign the emitter and detector. One embodiment of the adult probe includes a cushioning pocket formed for a fingertip to align the probe and to absorb motion of the probe due to contact. The neonatal probe is formed with a unique V-configuration which provides multiple advantages.

Dual-mode pulse oximeter

A pulse oximeter has an integrated mode in which it operates as a plug-in module for a multiparameter patient monitoring system (MPMS). The pulse oximeter also has a portable mode in which operates separately from the MPMS as a battery-powered handheld or standalone instrument. The pulse oximeter has a sensor port that receives a photo-plethysmographic signal as input to an internal processor. The pulse oximeter processes this sensor signal to derive oxygen saturation and pulse rate measurements. In the portable mode, this information is provided on its display, and stored in memory for trend capability. In the integrated mode, the pulse oximeter provides oxygen saturation and pulse rate measurements to the MPMS through a docking station to be displayed on a MPMS monitor. In the integrated mode, the portable pulse oximeter docks to the docking station, which in turn is inserted in one or more MPMS slots. The docking station can function as a simple electrical pass-through device between ...

Respiration processor

Respiratory rate can be calculated from an acoustic input signal using time domain and frequency domain techniques. Confidence in the calculated respiratory rate can also be calculated using time domain and frequency domain techniques. Overall respiratory rate and confidence values can be obtained from the time and frequency domain calculations. The overall respiratory rate and confidence values can be output for presentation to a clinician.

SIGNAL PROCESSING APPARATUS

The present invention involves a method and an apparatus for analyzing measured signals, including the determination of a measurement of oxygen saturation and respiration rate in the measured signals during a calculation of a physiological parameter of a monitored patient. Use of this invention is described in particular detail with respect to oximetry-based measurements. 1. A non-invasive optical based physiological monitoring system configured to determine a plurality of physiological parameters , the monitoring system comprising:a plurality of light emitting elements configured to emit light of at least two different wavelengths into tissue of a patient;a detector configured to detect the light of the at least two different wavelengths after it has been attenuated by the patients tissue and produce a signal indicative of the detected light; anda processing system configured to receive the signal produced by the detector and to process the signal in order to determine a first signal component indicative of a first physiological parameter and a second signal component indicative of a second physiological parameter;wherein the first physiological parameter is oxygen saturation and the second physiological parameter is respiration rate.2. The non-invasive optical based physiological monitoring system of claim 1 , wherein the processing system uses a wavelet transform to process the signal.3. The non-invasive optical based physiological monitoring system of claim 1 , further comprising determining a heart rate measurement.4. The non-invasive optical based physiological monitoring system of claim 1 , wherein processing the signal further comprises correlation cancelling techniques.5. The non-invasive optical based physiological monitoring system of claim 4 , wherein the correlation cancelling techniques comprises an adaptive noise canceller.6. The non-invasive optical based physiological monitoring system of claim 1 , wherein the second signal component is a reference ...

MANUAL AND AUTOMATIC PROBE CALIBRATION

Embodiments of the present disclosure include an optical probe capable of communicating identification information to a patient monitor in addition to signals indicative of intensities of light after attenuation by body tissue. The identification information may indicate operating wavelengths of light sources, indicate a type of probe, such as, for example, that the probe is an adult probe, a pediatric probe, a neonatal probe, a disposable probe, a reusable probe, or the like. The information could also be utilized for security purposes, such as, for example, to ensure that the probe is configured properly for the oximeter, to indicate that the probe is from an authorized supplier, or the like. 1. In a pulse oximetry system which uses interchangeable sensors having a plurality of light emitting devices , a method of identifying information about the sensor , the method comprising:determining operating characteristics of a sensor;coding the operating characteristics on a semiconductor device housed in the sensor; andreading the coded operating characteristics from the sensor onto a patient monitoring device.2. The method of claim 1 , where in the operating characteristics indicates a type of sensor.3. The method of claim 1 , wherein operating characteristics comprises calibration data.4. The method of claim 1 , wherein operating characteristics comprises security information.5. A disposable optical sensor configured to be used in a physiological monitoring system claim 1 , the sensor comprising:a first light emitting device;a second light emitting device;a detector configured to detect light produced by the first and second light emitting devices after attenuation by patient tissue;a semiconductor device housing predetermined unique operating characteristics of the first and second light emitting devices; anda connector configured to connect to a patient monitoring device and allow the patient monitoring device to read information from the semiconductor device.6. The ...

NONINVASIVE MULTI-PARAMETER PATIENT MONITOR

Embodiments of the present disclosure include a handheld multi-parameter patient monitor capable of determining multiple physiological parameters from the output of a light sensitive detector capable of detecting light attenuated by body tissue. For example, in an embodiment, the monitor is capable of advantageously and accurately displaying one or more of pulse rate, plethysmograph data, perfusion quality, signal confidence, and values of blood constituents in body tissue, including for example, arterial carbon monoxide saturation (“HbCO”), methemoglobin saturation (“HbMet”), total hemoglobin (“Hbt”), arterial oxygen saturation (“SpO”), fractional arterial oxygen saturation (“SpaO”), or the like. In an embodiment, the monitor advantageously includes a plurality of display modes enabling more parameter data to be displayed than the available physical display real estate. 1. A method of graphically displaying a plurality of physiological measurements on a single display , the method comprising:obtaining a first physiological measurement;obtaining a second physiological measurement;displaying an indication of the first physiological measurement on a first display area;displaying an indication of the second physiological measurement on the first display area, wherein the first display area alternates between displaying the indication of the first physiological measurement and the indication of the second physiological measurement;automatically switching between the indication of the first physiological measurement and the indication of the second physiological measurement without human intervention when a trend of either the first physiological measurement or the second physiological measurement indicate an alarm condition.2. The method of claim 1 , wherein the first physiological measurement is one of carbon monoxide saturation claim 1 , methemoglobin saturation claim 1 , total hemoglobin claim 1 , oxygen saturation claim 1 , and fractional oxygen saturation.3. The ...

METHOD AND APPARATUS FOR DEMODULATING SIGNALS IN A PULSE OXIMETRY SYSTEM

A method and an apparatus measure blood oxygenation in a subject. A light source is activated to cause a first emission at a first wavelength and a second emission at a second wavelength. A detector detects a composite signal indicative of an attenuation of the first and second wavelengths by tissue of a patient. The composite signal is demodulated into a first intensity signal and a second intensity signal. Blood oxygenation in the subject is determined from the first and second intensity signals. 1. A method of determining an indication of a physiological parameter by demodulating a composite output signal from a detector of a noninvasive optical sensor , the method comprising:activating at least one light source to cause a first emission at a first wavelength; activating the at least one light source to cause a second emission at a second wavelength at least once before a reactivation of the at least one light source;detecting the composite output signal indicative of an attenuation by said body tissue of said first and second emissions;selectively demodulating only certain harmonics of the detected composite signal into a first intensity signal responsive to said attenuation of said first emission and a second intensity signal responsive to said attenuation of said second emission by selectively; anddetermining an indication of a physiological parameter of said body tissue based on one or more of said first and second intensity signals.2. The method of claim 1 , wherein demodulating further comprises sampling said composite signal at a high frequency and decimating the sampled composite signal.3. The method of claim 2 , wherein decimating comprises using a lowpass filter followed by a sample rate compression.4. The method of claim 3 , wherein demodulating further comprises using feedback.5. A system for determining an indication of a physiological parameter by demodulating a composite output signal from a detector of a noninvasive oximetry optical sensor claim 3 ...

SIGNAL PROCESSING APPARATUS AND METHOD

A method and an apparatus to analyze two measured signals that are modeled as containing desired and undesired portions such as noise, FM and AM modulation. Coefficients relate the two signals according to a model defined. The method and apparatus are particularly advantageous to blood oximetry and pulserate measurements. 1. A noninvasive physiological monitor comprising:a first input for receiving an output waveform from a detector responsive light attenuated by body tissue, the output waveform including at least a first waveform corresponding to a first wavelength of light attenuated by body tissue and a second waveform corresponding to a second wavelength of light attenuated by body tissue;a signal processor configured to transform said first and second waveforms into spectral domain waveforms, the processor further configured to select spectral data based on predetermined criteria, the signal processor further configured to determine a physiological indication of the patient based on the selected spectral data.2. The noninvasive physiological monitor of claim 1 , wherein the physiological indication is pulse rate.3. The noninvasive physiological monitor of claim 1 , wherein the criteria is largest spectral peak.4. The noninvasive physiological monitor of claim 1 , wherein the criteria is a peak with corresponding harmonics.5. The noninvasive physiological monitor of claim 1 , wherein the criteria is a spectral peak in a predetermined range.6. A method of determining physiological information noninvasively based on optical measurements claim 1 , the method comprising:receiving, from a detector, a waveform indicative of tissue attenuated light detected by the detector, the waveform including at least a first waveform corresponding to a first a wavelength of light attenuated by body tissue and a second waveform correspond to a second wavelength of light attenuated by body tissue;transforming said first and second waveforms into spectral domain waveforms, the ...

SIGNAL PROCESSING APPARATUS AND METHOD

A method and an apparatus to analyze two measured signals that are modeled as containing desired and undesired portions such as noise, FM and AM modulation. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, a transformation is used to evaluate a ratio of the two measured signals in order to find appropriate coefficients. The measured signals are then fed into a signal scrubber which uses the coefficients to remove the unwanted portions. The signal scrubbing is performed in either the time domain or in the frequency domain. The method and apparatus are particularly advantageous to blood oximetry and pulserate measurements. In another embodiment, an estimate of the pulserate is obtained by applying a set of rules to a spectral transform of the scrubbed signal. In another embodiment, an estimate of the pulserate is obtained by transforming the scrubbed signal from a first spectral domain into a second spectral domain. The pulserate is found by identifying the largest spectral peak in the second spectral domain. 110-. (canceled)11. A pulse oximetry system for the determination of a physiological parameter wherein said pulse oximetry system is configured to remove motion artifacts from physiological signals , comprising:an optical sensor for providing said pulse oximetry system with photo-plethysmographic data, wherein said sensor comprises a light emitting diode for emitting light and a photo-detector for detecting said light, wherein said detected light contains information on the photo-plethysmographic data; and (a) acquire said photo-plethysmographic data;', '(b) transform the photo-plethysmographic data into frequency domain data;', '(c) analyze the frequency domain data;', '(d) reconstruct a time domain data photo-plethysmographic signal from said frequency domain data;', '(e) analyze a mathematical transformation of the time domain photo-plethysmographic signal to identify parameters;', '( ...

PHYSIOLOGICAL MONITOR

A patient monitor has multiple sensors adapted to attach to tissue sites of a living subject. The sensors generate sensor signals that are responsive to at least two wavelengths of optical radiation after attenuation by pulsatile blood within the tissue sites. 1. (canceled)2. A patient monitor capable of measuring at least two physiological parameters , the patient monitor comprising:a display capable of displaying a measured value of a first physiological parameter of body tissue of a monitored patient in a common portion of the display or displaying a measured value of a second physiological parameter of the body tissue in the common portion of the display,wherein the common portion of the display changes to displaying, at least, the other of the measured values based on an occurrence of a triggering event.3. The patient monitor of claim 2 , wherein claim 2 , based on the triggering event claim 2 , the common portion of the display changes from displaying one of the measured values of the first or second physiological parameters to displaying the other of the measured values.4. The patient monitor of claim 2 , wherein the triggering event comprises an alarm condition.5. The patient monitor of claim 2 , wherein the common portion of the display is configured to display the first physiological parameter and the second physiological parameter after the occurrence of the triggering event.6. The patient monitor of claim 2 , wherein activation of a user input causes the common display area to change from displaying one of the measured values of the first or second physiological parameter to displaying the other of the measured value of the first or second physiological parameter.7. The patient monitor of claim 2 , wherein the common display area is configured to default to displaying one of the measured values of the first or second physiological parameters.8. The patient monitor of claim 2 , wherein the measured value of the first physiological parameter comprises an ...

Hypersaturation index

Embodiments of the present disclosure provide a hypersaturation index for measuring a patient's absorption of oxygen in the blood stream after a patient has reached 100% oxygen saturation. This hypersaturation index provides an indication of the partial pressure of oxygen of a patient. In an embodiment of the present invention, a hypersaturation index is calculated based on the absorption ratio of two different wavelengths of energy at a measuring site. In an embodiment of the invention, a maximum hypersaturation index threshold is determined such that an alarm is triggered when the hypersaturation index reaches or exceeds the threshold. In another embodiment, an alarm is triggered when the hypersaturation index reaches or falls below its starting point when it was first calculated.

PHYSIOLOGICAL PARAMETER TRACKING SYSTEM

A physiological parameter tracking system has a reference parameter calculator configured to provide a reference parameter responsive to a physiological signal input. A physiological measurement output is a physiological parameter derived from the physiological signal input during a favorable condition and an estimate of the physiological parameter according to the reference parameter during an unfavorable condition. 1. A physiological parameter tracking method comprising the steps of:providing a noninvasive physiological sensor that detects light of at least first and second wavelengths transmitted through body tissue carrying pulsing blood;inputting a physiological signal from the physiological sensor;calculating a reference parameter responsive to the physiological signal;calculating an ancillary parameter responsive to the physiological signal;calculating a slow parameter based at least in part on the reference parameter and the ancillary parameter, wherein the slow parameter varies slowly in time relative to the reference parameter and the ancillary parameter; anddetermining a physiological measurement responsive to the reference parameter and the slow parameter.2. The method of claim 1 , wherein the calculating said ancillary parameter comprises determining whether a calculation of the ancillary parameter is favorable claim 1 , wherein the duration of an unfavorable calculation corresponds to a first time interval and the duration of a favorable calculation corresponds to a second time interval.3. The method of claim 2 , wherein the determining said physiological measurement further comprises calculating the physiological measurement as a function of the reference parameter and the slow parameter during the first time interval.4. The method of claim 2 , wherein the determining said physiological measurement further comprises outputting the ancillary parameter during the second time interval.5. The method of claim 1 , wherein the calculating said slow parameter ...

Systems and methods for determining blood oxygen saturation values using complex number encoding

The disclosure includes pulse oximetry systems and methods for determining point-by-point saturation values by encoding photoplethysmographs in the complex domain and processing the complex signals. The systems filter motion artifacts and other noise using a variety of techniques, including statistical analysis such as correlation, or phase filtering.

MULTI-WAVELENGTH PHYSIOLOGICAL MONITOR

A physiological monitor for determining blood oxygen saturation of a medical patient includes a sensor, a signal processor and a display. The sensor includes at least three light emitting diodes. Each light emitting diode is adapted to emit light of a different wavelength. The sensor also includes a detector, where the detector is adapted to receive light from the three light emitting diodes after being attenuated by tissue. The detector generates an output signal based at least in part upon the received light. The signal processor determines blood oxygen saturation based at least upon the output signal, and the display provides an indication of the blood oxygen saturation. 1. A physiological monitor for determining blood oxygen saturation of a patient , the physiological monitor comprising: three or more emitters, wherein each emitter is operative to emit light of a different wavelength; and', 'at least one detector adapted to receive light from the three or more emitters after being attenuated by tissue of a medical patient; and, 'a pulse oximetry sensor comprising compute a ratio based at least in part on three or more data signals, each of the three or more data signals indicative of light from one of the three or more emitters after being attenuated by the tissue, wherein the ratio comprises a quotient of a first weighted sum of the data signals multiplied by a first set of vector coefficients and a second weighted sum of the data signals multiplied by a second set of vector coefficients; and', 'determine blood oxygen saturation based at least in part upon a blood oxygen saturation curve using said ratio., 'a processor configured to2. The physiological monitor of claim 1 , wherein the first and second sets of vector coefficients are determined based upon calibration data or fitting of experimental data.3. The physiological monitor of claim 1 , wherein the at least one detector provides an output signal based at least in part on the received light and the ...

SIGNAL PROCESSING APPARATUS

The present invention involves a method and an apparatus for analyzing measured signals, including the determination of a measurement of oxygen saturation and respiration rate in the measured signals during a calculation of a physiological parameter of a monitored patient. Use of this invention is described in particular detail with respect to oximetry-based measurements but extends to other types of measurements. 1. A patient monitoring system configured to determine one or more physiological characteristics of a patient , the system comprising:a plurality of light emitters configured to emit light of at least two different wavelengths into tissue of a patient;a detector configured to detect the emitted light after attenuation by the tissue and output a signal indicative of the detected light; anda processing system configured to receive and process the detected light and determine information indicative of oxygen saturation, pulse rate and respiration rate, the processing system configured to reduce an effect of motion noise by using at least a frequency domain calculation.2. The patient monitoring system of claim 1 , wherein the frequency domain calculation comprises a Fourier transform.3. The patient monitoring system of claim 1 , wherein the processing system is further configured to determining a plurality of ratios of values based on the at least two different wavelengths.4. The patient monitoring system of claim 1 , wherein the processing system is further configured to use at least a wavelet transform in the determination of at least a portion of the information.5. The patient monitoring system of claim 1 , wherein the information comprises a primary signal and a reference signal claim 1 , the primary signal indicative of the oxygen saturation and the reference signal indicative of the respiration rate.6. A patient monitor configured to determine one or more physiological characteristics of a patient claim 1 , the system comprising:an input for receiving ...

PHYSIOLOGICAL MONITORING OF MOVING VEHICLE OPERATORS

The present disclosure relates to determining an physical state of a moving vehicle operator. In an embodiment, if it is determined that a vehicle operator is impaired, the vehicle is programed to automatically and safely stop a vehicle before an accident occurs. In an embodiment physiological sensors in the seat, steering wheel, or wireless sensors placed on the vehicle operator's body are used to determine an impairment state of a vehicle operator. 1. A vehicle operator physiological monitoring system comprising:a physiological monitor configured to measure a physiological state of a vehicle operator;a processor in communication with the physiological monitor that determines if the operator is impaired and automatically takes control of the vehicle to prevent an accident.2. The system of claim 1 , wherein the physiological sensor is located in an operator's seat.3. The system of claim 1 , wherein the physiological sensor is located in a steering wheel.4. The system of claim 1 , wherein the physiological sensor is located in a hat worn by the operator.5. The system of claim 1 , wherein the physiological sensor is located a glove worn by the operator.6. The system of claim 1 , wherein the physiological sensor is located in a Bluetooth device worn by the operator.7. A system configured to monitor a physiological state of a vehicle operator claim 1 , the system comprising:a vehicle operator seat;at least one light emitter; andat least one light detector, wherein the at least one light emitter and the at least one light detector are housed and form part of the vehicle operator seat.8. The system of claim 7 , wherein the at least one light emitter is configured to be shine light into the leg or buttocks of a vehicle operator;9. The system of claim 8 , wherein the at least one light emitter and the at leaste one light detector are placed below at least a first layer of fabric of the vehicle operator seat.10. A method of determining a physiological state of a vehicle ...

DUAL-MODE PATIENT MONITOR

A portable patient monitor has an integrated mode in which it operates as a plug-in module for a multiparameter patient monitoring system (MPMS). The patient monitor also has a portable mode in which it operates separately from the MPMS as a battery-powered handheld or standalone instrument. The patient monitor has a sensor port that receives a signal indicative of physiological parameters as input to an internal processor. The patient monitor processes this sensor signal to derive patient measurements. In the portable mode, this information is provided on its display. In the integrated mode, the patient monitor provides patient measurements to the MPMS to be displayed on a MPMS monitor. 1. A multi-monitor system for monitoring physiological parameters of a patient , the system comprising:A portable monitor including a portable display and a portable processor, said portable monitor configured to operate in a portable mode and a docked mode, said portable monitor also configured to communicate with a noninvasive sensor, said portable processor configured to process signals from said noninvasive sensor to determine display values of physiological parameters of the patient, wherein when operating in said portable mode, said portable monitor operates as a standalone monitor to communicate at least some of said display values to said portable display for caregiver review; andA multi-parameter monitor including a display other than said portable display and a plurality of receptacles, at least one of the receptacles configured to physically position and electrically communicate with a parameter processor different than said portable processor, said parameter processor configured to process signals other than said signals from said noninvasive sensor associated with said portable monitor to determine display values of physiological parameters of the patient and to communicate at least some of said determined display values to said display for caregiver review, and at ...

PULSE OXIMETER PROBE-OFF DETECTOR

A processor provides signal quality based limits to a signal strength operating region of a pulse oximeter. These limits are superimposed on the typical gain dependent signal strength limits. If a sensor signal appears physiologically generated, the pulse oximeter is allowed to operate with minimal signal strength, maximizing low perfusion performance. If a sensor signal is potentially due to a signal induced by a dislodged sensor, signal strength requirements are raised. Thus, signal quality limitations enhance probe off detection without significantly impacting low perfusion performance. One signal quality measure used is pulse rate density, which defines the percentage of time physiologically acceptable pulses are occurring. If the detected signal contains a significant percentage of unacceptable pulses, the minimum required signal strength is raised proportionately. Another signal quality measure used in conjunction with pulse rate density is energy ratio, computed as the percentage of total energy contained in the pulse rate fundamental and associated harmonics. 1. In a patient monitor configured to obtain signals responsive to physiological parameters of a monitored patient , a detector for determining when a physiological sensor may not be properly attached to said monitored patient with respect to a measurement site , the detector comprising:a limit selector configured to output a signal strength limit in response to a sensitivity mode; andlogic configured to indicate that a sensor not properly attached condition exists based on a comparison of a signal strength of one or more signals indicative of one or more physiological parameters and the signal strength limit.2. The detector of claim 1 , wherein the signal strength is based upon a ratio of a peak-to-peak AC signal to a DC signal.3. The detector of claim 2 , wherein the signal strength limit is about 0.05.4. The detector of claim 2 , wherein the signal strength limit is about 0.25.5. The detector of ...

HYPERSATURATION INDEX

Embodiments of the present disclosure provide a hypersaturation index for measuring a patient's absorption of oxygen in the blood stream after a patient has reached 100% oxygen saturation. This hypersaturation index provides an indication of the partial pressure of oxygen of a patient. In an embodiment of the present invention, a hypersaturation index is calculated based on the absorption ratio of two different wavelengths of energy at a measuring site. In an embodiment of the invention, a maximum hypersaturation index threshold is determined such that an alarm is triggered when the hypersaturation index reaches or exceeds the threshold. In another embodiment, an alarm is triggered when the hypersaturation index reaches or falls below its starting point when it was first calculated. 1. A method of measuring a quantity of oxygen dissolved in blood of a patient , the method comprising:emitting light of at least a first and second wavelength of light from a light emitter into a portion of a body of the patient;detecting the light after attenuation of the body, wherein the detected attenuation of the light is indicative of a physiological condition of the body of the patient;using the detected measures of the attenuations of the first and second wavelengths of light to determine a measure of a quantity of oxygen dissolved in the blood of a patient, where the measure indicates increasing dissolved oxygen in the blood above a 100% oxygen saturation condition of the patient; anddisplaying, using a displayed measurement separate from any oxygen saturation measurements, an indication the measure of the quantity of oxygen dissolved in the blood of the patient.2. The method of claim 1 , wherein the displayed measurement is an oxygen hypersaturation index.3. The method of claim 2 , wherein the hypersaturation index is an indication of the partial pressure of oxygen.4. The method of claim 2 , wherein the displayed measurement is a graph of the oxygen hypersaturation index.5. The ...

MULTIPLE WAVELENGTH SENSOR EMITTERS

A physiological sensor has light emitting sources, each activated by addressing at least one row and at least one column of an electrical grid. The light emitting sources are capable of transmitting light of multiple wavelengths and a detector is responsive to the transmitted light after attenuation by body tissue.

SIGNAL PROCESSING APPARATUS AND METHOD

A method and an apparatus to analyze two measured signals that are modeled as containing desired and undesired portions such as noise, FM and AM modulation. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, a transformation is used to evaluate a ratio of the two measured signals in order to find appropriate coefficients. The measured signals are then fed into a signal scrubber which uses the coefficients to remove the unwanted portions. The signal scrubbing is performed in either the time domain or in the frequency domain. The method and apparatus are particularly advantageous to blood oximetry and pulserate measurements. In another embodiment, an estimate of the pulserate is obtained by applying a set of rules to a spectral transform of the scrubbed signal. In another embodiment, an estimate of the pulserate is obtained by transforming the scrubbed signal from a first spectral domain into a second spectral domain. The pulserate is found by identifying the largest spectral peak in the second spectral domain. 1. A noninvasive physiological monitor comprising:a first input for receiving an output waveform from a detector responsive light attenuated by body tissue, the output waveform including at least a first waveform corresponding to a first wavelength of light attenuated by body tissue and a second waveform corresponding to a second wavelength of light attenuated by body tissue;a signal processor configured to transform said first and second waveforms into spectral domain waveforms, the processor further configured to select spectral data based on predetermined criteria, the signal processor further configured to determine a physiological, indication of the patient based on the selected spectral data.2. The noninvasive physiological monitor of claim 1 , wherein the physiological indication is pulse rate.3. The noninvasive physiological monitor of claim 1 , wherein the criteria is largest ...

PHYSIOLOGICAL MONITOR

A patient monitor has multiple sensors adapted to attach to tissue sites of a living subject. The sensors generate sensor signals that are responsive to at least two wavelengths of optical radiation after attenuation by pulsatile blood within the tissue sites. 1interface componentry in communication with at least two sensors each adapted to be positioned at one of at least two peripheral tissue sites, said interface componentry having outputs corresponding to signals received from each of the at least two sensors and responsive to light transmitted through a corresponding one of said sites; andat least one signal processor in communication with said interface componentry outputs, said at least one signal processor receiving the outputs from the interface componentry and determining an indication of oxygen saturation values from said sites in response to the outputs, said at least one signal processor further configured to compare at least one first oxygen saturation value from a first of said at least two sites with at least one second oxygen saturation value from a second of said at least two sites to determine the presence of a heart abnormality.. A physiological monitor comprising: This application is a continuation of U.S. application Ser. No. 13/745,590, filed Jan. 18, 2013, which is a continuation of U.S. application Ser. No. 11/417,931, filed May 3, 2006, now U.S. Pat. No. 8,364,223, which is a continuation of U.S. application Ser. No. 11/104,720, filed Apr. 13, 2005, now U.S. Pat. No. 7,761,128, which is a continuation of U.S. application Ser. No. 10/668,487, filed Sep. 22, 2003, now U.S. Pat. No. 6,898,452, which is a continuation of U.S. application Ser. No. 10/026,013, filed Dec. 21, 2001, now U.S. Pat. No. 6,714,804, which is a continuation of U.S. application Ser. No. 09/323,176, filed May 27, 1999, now U.S. Pat. No. 6,334,065, which claims priority from U.S. Provisional No. 60/087,802, filed Jun. 3, 1998.The measurement of oxygen delivery to the body ...

HYPERSATURATION INDEX

Embodiments of the present disclosure provide a hypersaturation index for measuring a patient's absorption of oxygen in the blood stream after a patient has reached 100% oxygen saturation. This hypersaturation index provides an indication of the partial pressure of oxygen of a patient. In an embodiment of the present invention, a hypersaturation index is calculated based on the absorption ratio of two different wavelengths of energy at a measuring site. In an embodiment of the invention, a maximum hypersaturation index threshold is determined such that an alarm is triggered when the hypersaturation index reaches or exceeds the threshold. In another embodiment, an alarm is triggered when the hypersaturation index reaches or falls below its starting point when it was first calculated. 1. (canceled)2. A noninvasive patient monitoring system for providing an indication of a patient's amount of oxygen reserves in the patient's body , the oxygen reserve being oxygen dissolved in the patient's blood during a hyperoxic state of the patient and different from a measure of a percentage of oxyhemoglobin in the blood at a time of measurement acquisition , the system comprising:one or more light emitters configured to emit at least a plurality of wavelengths of light into a portion of the patient's body;a light detector configured to detect the light after attenuation by the body and output one or more signals responsive to the attenuated light, the attenuation responsive to oxygenation of the patient's blood;one or more signal processors configured to process the one or more signals to electronically calculate an indicator responsive to the oxygen reserve, wherein the indicator is calculated based on a ratio of information from at least a first of the plurality of wavelengths and information from at least a second of the plurality of wavelengths during the hyperoxic state of the patient; anda display responsive to output of the one or more signal processors to electronically ...

Method and apparatus for calibration to reduce coupling between signals in a measurement system

A method and an apparatus for separating a composite signal into a plurality of signals is described. A signal processor receives a composite signal and separates a composite signal into separate output signals. Feedback from one or more of the output signals is provided to a configuration module that configures the signal processor to improve a quality of the output signals. In one embodiment, calibration data from multiple calibration data sets is used to configure the demodulation of the composite signal into separate output signals.

HYPERSATURATION INDEX

Embodiments of the present disclosure provide a hypersaturation index for measuring a patient's absorption of oxygen in the blood stream after a patient has reached 100% oxygen saturation. This hypersaturation index provides an indication of the partial pressure of oxygen of a patient. In an embodiment of the present invention, a hypersaturation index is calculated based on the absorption ratio of two different wavelengths of energy at a measuring site. In an embodiment of the invention, a maximum hypersaturation index threshold is determined such that an alarm is triggered when the hypersaturation index reaches or exceeds the threshold. In another embodiment, an alarm is triggered when the hypersaturation index reaches or falls below its starting point when it was first calculated. 1. (canceled)2. A pulse oximeter configured to measure an indication of oxygen saturation of a patient , the pulse oximeter comprising:one or more light emitters configured to emit light of at least two wavelengths of light into tissue of a patient;one or more detectors configured to output a signal responsive to detected light after attenuation by the tissue of the patient;one or more signal processors configured to receive the signal and determine at least one ratio from the signal, the at least one ratio comparing detected light of one of the at least two wavelengths to detected light of another of the at least two wavelengths, the one or more signal processors further configured to map the at least one ratio to either an oxygen saturation value or a hypersaturation value, wherein the ratio is mapped to a hypersaturation value if the ratio is below a first threshold and the ratio is mapped to an oxygen saturation value if the ratio is above the first threshold;displaying either the oxygen saturation value or the hypersaturation value.3. The pulse oximeter of claim 2 , wherein the first threshold is set at a ratio value that maps to a 100% oxygen saturation value.4. The pulse oximeter ...

NONINVASIVE MULTI-PARAMETER PATIENT MONITOR

Embodiments of the present disclosure include a handheld multi-parameter patient monitor capable of determining multiple physiological parameters from the output of a light sensitive detector capable of detecting light attenuated by body tissue. For example, in an embodiment, the monitor is capable of advantageously and accurately displaying one or more of pulse rate, plethysmograph data, perfusion quality, signal confidence, and values of blood constituents in body tissue, including for example, arterial carbon monoxide saturation (“HbCO”), methemoglobin saturation (“HbMet”), total hemoglobin (“Hbt”), arterial oxygen saturation (“SpO”), fractional arterial oxygen saturation (“SpaO”), or the like. The monitor can determine which a plurality of light emitting sources and which of a plurality of parameters to measure based on the signal quality and resources available. 1. A method of determining which of a plurality of physiological measurements to measure based on the signal quality of the signal , the method comprising:using a sensor configured to measure at least two different physiological measurements to obtain a signal from a light sensitive detector, the sensor including at least three different light emitters emitting at least three different wavelengths of light through tissue of a living patient and detecting the light after attenuation of the tissue;determining a signal quality of the signal;determining which of the at least two different physiological measurements are capable of being measured based on the signal quality determination; andactivating only enough of the at least three different light emitters necessary to obtain the measurements capable of being measured.2. The method of claim 1 , wherein if the signal quality is high claim 1 , all of the at least three different emitters are activated.3. The method of claim 1 , wherein if the signal quality is low claim 1 , only two of the at least three different emitters are activated.4. The method of ...

Physiological parameter confidence measure

Confidence in a physiological parameter is measured from physiological data responsive to the intensity of multiple wavelengths of optical radiation after tissue attenuation. The physiological parameter is estimated based upon the physiological data. Reference data clusters are stored according to known values of the physiological parameter. At least one of the data clusters is selected according to the estimated physiological parameter. The confidence measure is determined from a comparison of the selected data clusters and the physiological data.

Pulse and active pulse spectraphotometry

A pulse and active pulse spectraphotometry system comprises a light source adapted to illuminate a tissue site with optical radiation having a plurality of wavelengths selected from at least one of a primary band of about 1620 nm to about 1730 nm and a secondary band of about 1000 nm to about 1380 nm.

RESPIRATORY MONITORING

A patient interface in accordance with one embodiment of the present invention is configured to be at least partially carried by a patient and to receive gas exhaled by the patient. The patient interface includes first and second cannula tubes each having a first end and a second end, the first ends are configured to be inserted into the nostrils of a patient, the first and second cannula tubes are configured to direct exhaled gas from the patient from the first ends to said second ends. The patient interface also includes first and second sensors positioned near the second ends, and the first and second sensors are configured to provide first and second signals based upon the gas, wherein the first and second signals are indicative of a physiological parameter of the patient. The patient interface also includes a communications link configured to provide the signal to a physiological monitor. 1. (canceled)2. A method of detecting a physiological parameter of a patient , comprising: a plurality of sensors each configured, when activated, to provide a signal indicative of a physiological parameter of the patient based on the gas; and', 'a sensor selector configured to cause the gas exhaled by the patient to be directed to an active sensor, the active sensor selected from the plurality of sensors., 'receiving, in a sensing module, gas exhaled by a patient, the sensing module comprising3. The method of claim 2 , wherein when a predetermined event occurs claim 2 , the sensor selector directs the gas to a second sensor selected from the plurality of sensors.4. The method of claim 3 , wherein the predetermined event is at least one of:an accuracy of the active sensor falling below a predetermined level, an end of a useful life of the active sensor, a passing of a predetermined amount of time, or a triggering of an alarm based on an expiration of a timer.5. The method of claim 2 , wherein at least one of the plurality of sensors does not receive gas at a particular time.6. ...

MULTIPLE WAVELENGTH SENSOR EMITTERS

A physiological sensor has light emitting sources, each activated by addressing at least one row and at least one column of an electrical grid. The light emitting sources are capable of transmitting light of multiple wavelengths and a detector is responsive to the transmitted light after attenuation by body tissue. 1a plurality of light emitting sources, each light emitting source activated by addressing at least one of a plurality of rows and at least one of a plurality of columns of an electrical grid, the light emitting sources capable of transmitting light of a plurality of wavelengths; anda detector responsive to the transmitted light after attenuation by body tissue.. A physiological sensor comprising: The present application is a continuation of U.S. patent application Ser. No. 13/776,065, filed Feb. 25, 2013, entitled “Multiple Wavelength Sensor Emitters,” which is a continuation of U.S. patent application Ser. No. 12/422,915, filed Apr. 13, 2009, entitled “Multiple Wavelength Sensor Emitters,” which is a continuation of U.S. patent application Ser. No. 11/367,013, filed Mar. 1, 2006, entitled “Multiple Wavelength Sensor Emitters,” which claims priority benefit under 35 U.S.C. §119(e) to U.S. Provisional Pat. App. No. 60/657,596, filed Mar. 1, 2005, entitled “Multiple Wavelength Sensor,” No. 60/657,281, filed Mar. 1, 2005, entitled “Physiological Parameter Confidence Measure,” No. 60/657,268, filed Mar. 1, 2005, entitled “Configurable Physiological Measurement System,” and No. 60/657,759, filed Mar. 1, 2005, entitled “Noninvasive Multi-Parameter Patient Monitor.” The present application incorporates the foregoing disclosures herein by reference in their entirety.The present application is related to the following U.S. utility applications:The present application incorporates the foregoing disclosures herein by reference.Spectroscopy is a common technique for measuring the concentration of organic and some inorganic constituents of a solution. The theoretical ...

METHOD AND APPARATUS FOR CALIBRATION TO REDUCE COUPLING BETWEEN SIGNALS IN A MEASUREMENT SYSTEM

A method and an apparatus for separating a composite signal into a plurality of signals is described. A signal processor receives a composite signal and separates a composite signal into separate output signals. Feedback from one or more of the output signals is provided to a configuration module that configures the signal processor to improve a quality of the output signals. In one embodiment, calibration data from multiple calibration data sets is used to configure the demodulation of the composite signal into separate output signals. 1. An apparatus for measuring one or more blood constituents in a subject , said apparatus comprising:a first signal source which applies a first input signal during a first time interval;a second signal source which applies a second input signal during a second time interval;a third signal source which applies a second input signal during a third time interval;a detector which detects a first parametric signal responsive to said first input signal passing through a portion of said subject having blood therein, a second parametric signal responsive to said second input signal passing through said portion of said subject, and a third parametric signal responsive to said third input signal passing through a portion of said subject having blood therein, said detector generating a detector output signal responsive to said first, second, and third parametric signals; anda signal processor which receives said detector output signal, said signal processor configured to demodulate said detector output signal by applying a first demodulation signal to a signal responsive to said detector output signal to generate a first demodulator output signal, applying a second demodulation signal to said signal responsive to said detector output signal to generate a second demodulator output signal, and applying a third demodulation signal to said signal responsive to said detector output signal to generate a third demodulator output signal, said signal ...

Robust alarm system

A robust alarm system has an alarm controller adapted to input an alarm trigger and to generate at least one alarm drive signal in response. Alarm subsystems input the alarm drive signal and activate one or more of multiple alarms accordingly. A subsystem function signal provides feedback to the alarm controller as to alarm subsystem integrity. A malfunction indicator is output from the alarm controller in response to a failure within the alarm subsystems.

METHOD AND APPARATUS FOR DEMODULATING SIGNALS IN A PULSE OXIMETRY SYSTEM

A method and an apparatus measure blood oxygenation in a subject. A light source is activated to cause a first emission at a first wavelength and a second emission at a second wavelength. A detector detects a composite signal indicative of an attenuation of the first and second wavelengths by tissue of a patient. The composite signal is demodulated into a first intensity signal and a second intensity signal. Blood oxygenation in the subject is determined from the first and second intensity signals. 1. A system which measures one or more physiological characteristics of a living subject non-invasively by measuring pulsing light of two or more wavelengths after attenuation by body tissue , the system comprising:at least one emitter configured to emit light of at least two or more different wavelengths using a modulation scheme that cycles the at least two or more different wavelengths, the at least one emitter positioned to emit light in the direction of a living subject;at least one detector configured to detect the light of the at least two or more different wavelengths emitted from the at least one detector after the light has been attenuated by tissue of the living subject, the detector further configured to generate a detector signal representative of the emitted light;a demodulation system configured to demodulate the detector signal, the demodulation system configured to adjust the demodulation of the detector signal to reduce crosstalk based, at least in part, on previously demodulated signal values.2. The system of claim 1 , the demodulation system is further configured to adjust the demodulation based on previously demodulated signal values during a period where one or more of the at least two different wavelengths is turned off.3. The system of claim 1 , wherein the demodulation is adjusted during an initial calibration period.4. The system of claim 3 , wherein the demodulation is adjusted during periodic calibration periods during measurement.5. The system ...

ASSEMBLY FOR MEDICAL MONITORING DEVICE WITH MULTIPLE PHYSIOLOGICAL SENSORS

Systems, methods, and apparatuses for enabling a plurality of non-invasive, physiological sensors to obtain physiological measurements from the same tissue site. Each of a plurality of sensors can be integrated with or attached to a multi-sensor apparatus. The multi-sensor apparatus can orient the plurality of non-invasive, physiological sensors such that each of the plurality of non-invasive, physiological sensors obtains physiological data from the same or a similar location. 1. A multi-sensor apparatus measuring physiological parameters from a tissue site of a patient , the apparatus comprising:a plurality of non-invasive sensors configured to obtain physiological data associated with a patient; and a frame configured to support each of the plurality of non-invasive sensors, and', 'a tissue interaction section configured to be proximate a tissue site of the patient, wherein each of the plurality of non-invasive sensors are configured to obtain physiological data associated with a patient at the tissue site., 'a sensor head comprising2. The apparatus of claim 1 , wherein the tissue interaction section comprises a different sensing region for each of the plurality of non-invasive sensors claim 1 , wherein a particular non-invasive sensor obtains the physiological data via the particular sensing region.3. The apparatus of claim 2 , wherein a distance between each of the sensing regions satisfies a distance threshold.4. The apparatus of claim 1 , wherein at least two of the plurality of noninvasive sensors are configured to simultaneously obtain the physiological data.5. The apparatus of claim 1 , wherein at least two of the plurality of noninvasive sensors are configured to obtain the physiological data at non-overlapping time intervals.6. The apparatus of claim 1 , wherein each of the plurality non-invasive physiological sensors obtains physiological data from of the same tissue site.7. The apparatus of claim 1 , wherein the plurality non-invasive physiological ...

PHYSIOLOGICAL MONITOR

A patient monitor has multiple sensors adapted to attach to tissue sites of a living subject. The sensors generate sensor signals that are responsive to at least two wavelengths of optical radiation after attenuation by pulsatile blood within the tissue sites. 1interface componentry in communication with at least two sensors each adapted to be positioned at one of at least two peripheral tissue sites, said interface componentry having outputs corresponding to signals received from each of the at least two sensors and responsive to light transmitted through a corresponding one of said sites; andat least one signal processor in communication with said interface componentry outputs, said at least one signal processor receiving the outputs from the interface componentry and determining an indication of oxygen saturation values from said sites in response to the outputs, said at least one signal processor further configured to compare at least one first oxygen saturation value from a first of said at least two sites with at least one second oxygen saturation value from a second of said at least two sites to determine the presence of a heart abnormality.. A physiological monitor comprising: Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are incorporated by reference under 37 CFR 1.57 and made a part of this specification.The measurement of oxygen delivery to the body and the corresponding oxygen consumption by its organs and tissues is vitally important to medical practitioners in the diagnosis and treatment of various medical conditions. Oxygen delivery, the transport of oxygen from the environment to organs and tissues, depends on the orchestration of several interrelated physiologic systems. Oxygen uptake is determined by the amount of oxygen entering the lung and the adequacy of gas exchange within the lung. This gas exchange is determined by the diffusion of ...

SYSTEMS AND METHODS FOR DETERMINING BLOOD OXYGEN SATURATION VALUES USING COMPLEX NUMBER ENCODING

The disclosure includes pulse oximetry systems and methods for determining point-by-point saturation values by encoding photoplethysmographs in the complex domain and processing the complex signals. The systems filter motion artifacts and other noise using a variety of techniques, including statistical analysis such as correlation, or phase filtering. 1a light emitter which emits light of at least first and second wavelengths;a light detector responsive to light from said light emitter attenuated by body tissue, said light detector providing an output signal indicative of at least first and second intensity signals associated with said at least first and second wavelengths; anda signal processor responsive to the first and second intensity signals to encode said first and second intensity signals in a complex time domain, to calculate arterial oxygen saturation from said encoded signals, and to output said saturation for caregiver review.. A physiological monitor that computes arterial oxygen saturation in tissue material, the physiological monitor comprising: The present application claims priority benefit under 35 U.S.C. §120 to, and is a continuation of, U.S. patent application Ser. No. 13/896,731, filed May 17, 2013, entitled “Systems and Methods for Determining Blood Oxygen Saturation Values Using Complex Number Encoding,” which is a continuation of U.S. patent application Ser. No. 12/248,868, filed Oct. 9, 2008, now U.S. Pat. No. 8,447,374, entitled “Systems and Methods for Determining Blood Oxygen Saturation Values Using Complex Number Encoding,” which is a continuation of U.S. patent application Ser. No. 11/288,812, filed Nov. 28, 2005, now U.S. Pat. No. 7,440,787, entitled “Systems and Methods for Determining Blood Oxygen Saturation Values Using Complex Number Encoding,” which is a continuation of U.S. patent application Ser. No. 10/727,348, filed Dec. 3, 2003, now U.S. Pat. No. 6,970,792, entitled “Systems and Methods for Determining Blood Oxygen ...

MANUAL AND AUTOMATIC PROBE CALIBRATION

Embodiments of the present disclosure include an optical probe capable of communicating identification information to a patient monitor in addition to signals indicative of intensities of light after attenuation by body tissue. The identification information may indicate operating wavelengths of light sources, indicate a type of probe, such as, for example, that the probe is an adult probe, a pediatric probe, a neonatal probe, a disposable probe, a reusable probe, or the like. The information could also be utilized for security purposes, such as, for example, to ensure that the probe is configured properly for the oximeter, to indicate that the probe is from an authorized supplier, or the like. 1. In a pulse oximetry system which uses interchangeable sensors having a plurality of light emitting devices , a method of identifying information about the sensor , the method comprising:determining operating characteristics of a sensor;coding the operating characteristics on a semiconductor device housed in the sensor; andreading the coded operating characteristics from the sensor onto a patient monitoring device.2. The method of claim 1 , where in the operating characteristics indicates a type of sensor.3. The method of claim 1 , wherein operating characteristics comprises calibration data.4. The method of claim 1 , wherein operating characteristics comprises security information.5. A disposable optical sensor configured to be used in a physiological monitoring system claim 1 , the sensor comprising:a first light emitting device;a second light emitting device;a detector configured to detect light produced by the first and second light emitting devices after attenuation by patient tissue;a semiconductor device housing predetermined unique operating characteristics of the first and second light emitting devices; anda connector configured to connect to a patient monitoring device and allow the patient monitoring device to read information from the semiconductor device.6. The ...

MULTIPLE WAVELENGTH SENSOR EMITTERS

A physiological sensor has light emitting sources, each activated by addressing at least one row and at least one column of an electrical grid. The light emitting sources are capable of transmitting light of multiple wavelengths and a detector is responsive to the transmitted light after attenuation by body tissue. 1. A physiological monitoring device comprising:at least two LEDs, the at least two LEDs configured to emit light of at least two different wavelengths;at least one detector configured to detect at least a portion of the light emitted from the at least two LEDs after at least a portion of the light has been attenuated by tissue, the at least one detector configured to output at least one signal responsive to the detected light;a light block surrounding the at least one detector, the light block forming a cavity, the light block comprising a light-absorbing material, the light block including only one circular opening through which light is configured to pass, an area of the circular opening being smaller than a surface area of a facing surface of the at least one detector; anda processor configured to receive and process one or more signals responsive to the outputted at least one signal and determine a physiological parameter of a user responsive to the one or more signals.2. The physiological monitoring device of claim 1 , wherein the at least two LEDs comprises at least eight LEDs.3. The physiological monitoring device of claim 2 , wherein the at least eight LEDs comprises at least two LEDs of the same wavelength.4. The physiological monitoring device of claim 1 , wherein the at least two LEDs comprises at least twelve LEDs.5. The physiological monitoring device of claim 1 , wherein multiple LEDs of the at least two LEDs are configured for concurrent activation.6. The physiological monitoring device of claim 1 , wherein the at least one detector comprises at least two detectors.7. The physiological monitoring device of claim 1 , further comprising an ...

Physiological parameter confidence measure

Confidence in a physiological parameter is measured from physiological data responsive to the intensity of multiple wavelengths of optical radiation after tissue attenuation. The physiological parameter is estimated based upon the physiological data. Reference data clusters are stored according to known values of the physiological parameter. At least one of the data clusters is selected according to the estimated physiological parameter. The confidence measure is determined from a comparison of the selected data clusters and the physiological data.

SYSTEMS AND METHODS FOR ACQUIRING CALIBRATION DATA USABLE IN A PULSE OXIMETER

The present disclosure includes a pulse oximeter attachment having an accessible memory. In one embodiment, the pulse oximeter attachment stores calibration data, such as, for example, calibration data associated with a type of a sensor, a calibration curve, or the like. The calibration data is used to calculate physiological parameters of pulsing blood. 1. A method for communicating a physiological waveform indicative of a physiological condition to a patient monitor , the method comprising:obtaining a sensor signal indicative of a physiological parameter;calculating a first physiological measurement using a first processor;communicating the physiological measurement to a second processor;constructing an output signal indicative of the physiological measurement; andcommunicating the output signal to the sensor input of a patient monitoring device for recalculation and display of the physiological measurement.2. The method of claim 1 , further comprising displaying the calculated physiological measurement on a first display associated with the first processor.3. The method of claim 1 , wherein the physiological measurement comprises at least one of blood oxygen levels claim 1 , blood pressure claim 1 , ECG claim 1 , and pulse rate.4. The method of claim 1 , wherein the output signal is configured to cause a patient monitor not associated with the first processor to calculate a second physiological measurement substantially equivalent to the first physiological measurement.5. The method of claim 1 , wherein the second processor comprises a waveform generator.6. The method of claim 1 , wherein the second processor is comprised within a docking station.7. A system for communicating a physiological waveform indicative of a physiological condition to a patient monitor claim 1 , the system comprising:a sensor input configured to obtain a sensor signal indicative of a physiological parameter;a first processor configured to calculate a first physiological measurement;a ...

ROBUST ALARM SYSTEM

A robust alarm system has an alarm controller adapted to input an alarm trigger and to generate at least one alarm drive signal in response. Alarm subsystems input the alarm drive signal and activate one or more of multiple alarms accordingly. A subsystem function signal provides feedback to the alarm controller as to alarm subsystem integrity. A malfunction indicator is output from the alarm controller in response to a failure within the alarm subsystems. 1. A patient monitoring device comprising:a driving circuit configured to drive one or more emitters;a front end processing circuit configured to receive a signal from a detector responsive to light from said emitters attenuated by body tissue;an alarm configured to provide an alert to a caregiver;a processor responsive to said front end to process said signal to determine one or more measurement values for one or more physiological parameters of a patient being monitored, said processor also configured to trigger said alarm when one or more of said measurement values should receive caregiver review;a malfunction indicator providing an alert that said alarm was nonresponsive when triggered by said processor.2. The monitoring device of claim 1 , wherein said malfunction indicator comprises a buzzer.3. The monitoring device of claim 1 , wherein said malfunction indicator comprises an audible alert.4. The monitoring device of claim 1 , wherein said alarm comprises a sound transducer.5. The monitoring device of claim 1 , wherein said alarm comprises a robust alarm.6. The monitoring device of claim 5 , wherein said robust alarm comprises an electronic circuit capable of determining whether said alarm was nonresponsive.7. The monitoring device of claim 6 , wherein the electronic circuit comprises a driver circuit driving said robust alarm and a tester configured to determine integrity of a driver circuit.8. The monitoring device of claim 5 , wherein said robust alarm comprises a plurality of sound transducers.9. A ...

METHOD AND APPARATUS FOR DEMODULATING SIGNALS IN A PULSE OXIMETRY SYSTEM

A method and an apparatus measure blood oxygenation in a subject. A light source is activated to cause a first emission at a first wavelength and a second emission at a second wavelength. A detector detects a composite signal indicative of an attenuation of the first and second wavelengths by tissue of a patient. The composite signal is demodulated into a first intensity signal and a second intensity signal. Blood oxygenation in the subject is determined from the first and second intensity signals. 1. A system which measures one or more physiological characteristics of a living subject non-invasively by measuring pulsing light of two or more wavelengths after attenuation by body tissue , the system comprising:at least one emitter configured to emit light of at least two or more different wavelengths using a modulation scheme that cycles the at least two or more different wavelengths, the at least one emitter positioned to emit light in the direction of a living subject;at least one detector configured to detect the light of the at least two or more different wavelengths emitted from the at least one detector after the light has been attenuated by tissue of the living subject, the detector further configured to generate a detector signal representative of the emitted light;a demodulation system configured to demodulate the detector signal, the demodulation system configured to adjust the demodulation of the detector signal to reduce crosstalk based, at least in part, on previously demodulated signal values.2. The system of claim 1 , the demodulation system is further configured to adjust the demodulation based on previously demodulated signal values during a period where one or more of the at least two different wavelengths is turned off.3. The system of claim 1 , wherein the demodulation is adjusted during an initial calibration period.4. The system of claim 3 , wherein the demodulation is adjusted during periodic calibration periods during measurement.5. The system ...

MULTIPLE WAVELENGTH SENSOR EMITTERS

A physiological sensor has light emitting sources, each activated by addressing at least one row and at least one column of an electrical grid. The light emitting sources are capable of transmitting light of multiple wavelengths and a detector is responsive to the transmitted light after attenuation by body tissue. 120-. (canceled)21. A physiological sensor comprising:a light source electrically coupled to a first row conductor of an electrical grid and a first column conductor of the electrical grid, wherein the light source is activated by addressing the first row conductor and the first column conductor; andan information element electrically coupled to a second row conductor and a second column conductor of the electrical grid, wherein the information element is activated by addressing the second row conductor and the second column conductor.22. The physiological sensor of claim 21 , further comprising the electrical grid claim 21 , wherein the electrical grid comprises:a plurality of row conductors including the first row conductor and the second row conductor; anda plurality of column conductors including the first column conductor and the second column conductor.23. The physiological sensor of claim 21 , further comprising a detector configured to:detect light emitted by the light source after the light interacts with tissue of a patient; andgenerate a signal responsive to the detected light.24. The physiological sensor of claim 21 , wherein claim 21 , in response to being activated claim 21 , the information element provides an output indicative of information relating to the physiological sensor claim 21 , wherein the information relating to the physiological sensor comprises an indication of at least one of a sensor type claim 21 , an authorized supplier claim 21 , an authorized manufacturer claim 21 , or a wavelength corresponding to light emitted by the light source.25. The physiological sensor of claim 24 , wherein the information element is configured ...

HYPERSATURATION INDEX

Embodiments of the present disclosure provide a hypersaturation index for measuring a patient's absorption of oxygen in the blood stream after a patient has reached % oxygen saturation. This hypersaturation index provides an indication of the partial pressure of oxygen of a patient. In an embodiment of the present invention, a hypersaturation index is calculated based on the absorption ratio of two different wavelengths of energy at a measuring site. In an embodiment of the invention, a maximum hypersaturation index threshold is determined such that an alarm is triggered when the hypersaturation index reaches or exceeds the threshold. In another embodiment, an alarm is triggered when the hypersaturation index reaches or falls below its starting point when it was first calculated. 1. (canceled)2. A pulse oximeter device configured to measure a rising oxygen saturation level , the device comprising: ["receive, from one or more detectors, light signals of at least first and second wavelengths after attenuation by a patient's body, the one or more detectors configured to output the signals responsive to detection of light emitted by one or more light emitters;", 'calculate a level of hypersaturation of the patient based on at least a ratio of the signals using the at least first and second wavelengths;', 'determine an amount of time for the level of hypersaturation to return from a hypersaturation state to a sub-100% oxygen saturation; and', 'display the amount of time., 'a physiological hardware processor configured to3. The device of claim 2 , wherein the amount of time includes a range of potential time left before the patient returns to the sub-100% oxygen saturation.4. The device of claim 3 , wherein the range decreases as the amount of time decreases.5. The device of claim 2 , further comprising a display configured to display a timer claim 2 , the timer configured to provide an indication of the amount of time.6. The device of claim 5 , wherein the timer includes ...

Aparato de procesamiento de señales.

La presente invencion se refiere a un método y a un aparato para analizar dos señales medidas recibidas por un detector que se modelan como conteniendo partes primarias y secundarias. Coeficientes relacionan las dos señales de conformidad con un modelo definido segun la presente invencion. En una modalidad, la presente invencion incluye el uso de una transformacion que evalua una pluralidad de posibles coeficientes de señales para encontrar coeficientes apropiados. Alternativamente, la presente invencion incluye el uso de funciones estadísticas o bien transformacion de Fourier así como técnicas de creacion de ventana para determinar los coeficientes relacionados con dos señales medidas. El uso de esta invencion se describe con detalles específicos en relacion a mediciones de oximetría de la sangre.

System and method for altering a display mode based on a gravity-responsive sensor

A sensor, such as, for example, a gravity-responsive sensor, provides an output used to select an orientation of a display of a display device. For example, the output may indicate that the orientation of the display should comprise a portrait or landscape orientation, an orientation rotated, such as, for example, ninety degrees (90°), one hundred and eighty degrees (180°), two hundred and seventy degrees (270°), or the like. In addition, one or more manual switches, buttons, or display icons may be actuated or otherwise selected to manually set the orientation of the display.

Dual-mode pulse oximeter

A pulse oximeter has an integrated mode in which it operates as a plug-in module for a multiparameter patient monitoring system (MPMS). The pulse oximeter also has a portable mode in which operates separately from the MPMS as a battery-powered handheld or standalone instrument. The pulse oximeter has a sensor port that receives a photo-plethysmographic signal as input to an internal processor. The pulse oximeter processes this sensor signal to derive oxygen saturation and pulse rate measurements. In the portable mode, this information is provided on its display, and stored in memory for trend capability. A keypad provides a user interface for operational control in the portable mode. In the integrated mode, the pulse oximeter provides oxygen saturation and pulse rate measurements to the MPMS through a communications interface, along with previously stored trend data, and displayed on the MPMS monitor. The MPMS also provides external power and operational control of the pulse oximeter in the integrated mode. Alternatively, a docking station operates as a plug-in module that provides the mechanical and electrical interface between a portable pulse oximeter and MPMS instruments from a variety of manufacturers. In the integrated mode, the portable pulse oximeter docks to the docking station, which in turn is inserted in one or more MPMS slots. The docking station can function as a simple electrical pass-through device between the docked portable pulse oximeter and the MPMS or it can provide a MPMS communications interface.

Stereo pulse oximeter

An improved pulse oximeter provides for simultaneous, noninvasive oxygen status and photoplethysmograph measurements at both single and multiple sites. In particular, this multiple-site, multiple-parameter pulse oximeter, or "stereo pulse oximeter" (100) simultaneously measures both arterial (SPA02) and venous (SPV02) oxygen saturation at any specific site and generates a corresponding plethysmograph waveform. A corresponding computation of arterial minus venous oxygen saturation is particularly advantageous for oxygen therapy management. An active pulse-inducing mechanism having a scattering-limited drive generates a consistent pulsatile venous signal utilized for the venous blood measurements. The stereo pulse oximeter also measures arterial oxygen saturation and plethysmograph shape parameters across multiple sites. A corresponding calculation of delta arterial saturation and comparison of plethysmograph shape parameters between multiple sites is particularly advantageous for the detection and management of persistant pulmonary hypertension in neonates (PPHN), a patent ductus arteriosis (PDA), and aortic coarctation.

Low noise optical probe

An optical probe for measurements, which is particularly suited to reduce noise in measurements taken on an easily compressible material, such as a finger, a toe, a forehead, an earlobe, or a lip. The probe includes a base having an aperture which leads to a chamber. The base is placed adjacent a portion of the material, the chamber being placed directly adjacent any easily compressible portion of the material. A photodetector is located within the chamber and does not contact the material. A light emitting diode (LED) is affixed to the material, opposite the photodetector and above the chamber. The material which is supported by the aperture and therefore rests above or has intruded into the chamber is inhibited from compression since nothing comes in contact with this portion of the material, even when the material moves. Thus, light from the LED is directed through a stabilized portion of the material, i.e., the optical path length through which light travels is stabilized, even during motion of the material. This reduces noise in the signal measured by the photodetector. A scattering medium is interposed between the LED and the material, between the material and the photodetector, or between the LED and the material as well as between the material and the photodetector. The scattering medium is used to improve the signal-to-noise ratio of the received optical signal.

Universal/upgrading pulse oximeter

A universal/upgrading pulse oximeter (UPO) comprises a portable unit and a docking station together providing three-instruments-in-one functionality for measuring oxygen saturation and related physiological parameters. The portable unit functions as a handheld pulse oximeter. The combination of the docked portable and the docking station functions as a stand-alone, high-performance pulse oximeter. The portable-docking station combination is also connectable to, and universally compatible with, pulse oximeters from various manufacturers through use of a waveform generator. The UPO provides a universal sensor to pulse oximeter interface and a pulse oximeter measurement capability that upgrades the performance of conventional instruments by increasing low perfusion performance and motion artefact immunity, for example. Universal compatibility combined with portability allows the UPO to be transported along with patients transferred between an ambulance and a hospital ER, or between various hospital sites, providing continuous patent monitoring in addition to plug-compatibility and functional upgrading for multiparameter patient monitoring systems. The image on the portable display is rotatable, either manually when undocked or as a function of orientation. In one embodiment, the docking station has a web server and a network interface that allows UPO data to be downloaded and viewed as web pages over a local area network or the Internet.

Blood glucose monitoring system

A blood glucose monitoring system includes a broadband light source and a specially fabricated optical filter for modulating optical radiation to be transmitted through a fleshy medium. Optical radiation which passes through the fleshy medium is detected by an optical detector which generates an electrical signal indicative of the intensity of the detected light. Digital signal processing is performed on the electrical signal to extract those optical characteristics of the electrical signal due to the optical characteristics of the filter and constituents of the fleshy May 1, 1995 medium other than blood glucose concentration. The monitoring system employs a unique "double-log" transformation to minimize errors due to indeterminate path length variations of the optical radiation through the fleshy medium. The monitoring system further employs specialized signal processing to avoid inaccuracies due to the previously unidentified solvent effect which arises when glucose is dissolved into water.

Signal processing apparatus

The present invention involves method and apparatus for analyzing two measured signals that are modeled as containing primary and secondary portions. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, the present invention involves utilizing a transformation which evaluates a plurality of possible signal coefficients in order to find appropriate coefficients. Alternatively, the present invention involves using statistical functions or Fourier transform and windowing techniques to determine the coefficients relating to two measured signals. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Signal processing apparatus

The present invention involves method and apparatus for analyzing two measured signals that are modeled as containing primary and secondary portions. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, the present invention involves utilizing a transformation which evaluates a plurality of possible signal coefficients in order to find appropriate coefficients. Alternatively, the present invention involves using statistical functions or Fourier transform and windowing techniques to determine the coefficients relating to two measured signals. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Universal/upgrading pulse oximeter

A universal/upgrading pulse oximeter (UPO) comprises a portable unit and a docking station together providing three-instruments-in-one functionality for measuring oxygen saturation and related physiological parameters. The portable unit functions as a handheld pulse oximeter. The combination of the docked portable and the docking station functions as a stand-alone, high-performance pulse oximeter. The portable-docking station combination is also connectable to, and universally compatible with, pulse oximeters from various manufacturers through use of a waveform generator. The UPO provides a universal sensor to pulse oximeter interface and a pulse oximeter measurement capability that upgrades the performance of conventional instruments by increasing low perfusion performance and motion artefact immunity, for example. Universal compatibility combined with portability allows the UPO to be transported along with patients transferred between an ambulance and a hospital ER, or between various hospital sites, providing continuous patient monitoring in addition to plug-compatibility and functional upgrading for multiparameter patient monitoring systems. The image on the portable display is rotatable, either manually when undocked or as a function of orientation. In one embodiment, the docking station has a web server and a network interface that allows UPO data to be downloaded and viewed as web pages over a local area network or the Internet.

Oximeter comprising a light source and an information element

Physiological parameter confidence measure

Confidence in a physiological parameter is measured from physiological data responsive to the intensity of multiple wavelengths of optical radiation after tissue attenuation. The physiological parameter is estimated based upon the physiological data. Reference data clusters are stored according to known values of the physiological parameter. At least one of the data clusters is selected according to the estimated physiological parameter. The confidence measure is determined from a comparison of the selected data clusters and the physiological data

Signal processing apparatus

The present invention involves a method and an apparatus for analyzing measured signals, including the determination of a measurement of correlation in the measured signals during a calculation of a physiological parameter of a monitored patient. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Signal processing apparatus

The present disclosure describes a method and an apparatus for analyzing measured signals using various processing techniques. In certain embodiments, the measured signals are physiological signals. In certain embodiments, the measurements relate to blood constituent measurements including blood oxygen saturation.

Universal/upgrading pulse oximeter

A universal/upgrading pulse oximeter (UPO) (210) comprises a portable unit (610) and a docking station (660, 910) together providing three-instruments-in-one functionality for measuring oxygen saturation and related physiological parameters. The portable unit functions as a handheld pulse oximeter. The combination of the docked portable and the docking station functions as a stand-alone, high-performance pulse oximeter. The portable-docking station combination is also connectable to, and universally compatible with, pulse oximeters from various manufacturers through use of a waveform generator (320, 930). The UPO provides a universal sensor to pulse oximeter interface and a pulse oximeter measurement capability that upgrades the performance of conventional instruments by increasing low perfusion performance and motion artifact immunity, for example. Universal compatibility combined with portability allows the UPO to be transported along with patients transferred between an ambulance and a hospital ER, or between various hospital sites, providing continuous patient monitoring in addition to plug-compatibility and functional upgrading for multiparameter patient monitoring systems. The image on the portable display (264, 740) is rotatable, either manually when undocked or as a function of orientation (950). In one embodiment, the docking station (660) has a web server and network interface (1410) that allows UPO data to be downloaded and viewed as web pages over a local area network (1420) or the Internet.

Universal/upgrading pulse oximeter

A universal/upgrading pulse oximeter (UPO) (210) comprises a portable unit (610) and a docking station (660, 910) together providing three-instruments-in-one functionality for measuring oxygen saturation and related physiological parameters. The portable unit functions as a handheld pulse oximeter. The combination of the docked portable and the docking station functions as a stand-alone, high-performance pulse oximeter. The portable-docking station combination is also connectable to, and universally compatible with, pulse oximeters from various manufacturers through use of a waveform generator (320, 930). The UPO provides a universal sensor to pulse oximeter interface and a pulse oximeter measurement capability that upgrades the performance of conventional instruments by increasing low perfusion performance and motion artifact immunity, for example. Universal compatibility combined with portability allows the UPO to be transported along with patients transferred between an ambulance and a hospital ER, or between various hospital sites, providing continuous patient monitoring in addition to plug-compatibility and functional upgrading for multiparameter patient monitoring systems. The image on the portable display (264, 740) is rotatable, either manually when undocked or as a function of orientation (950), In one embodiment, the docking station (660) has a web server and network interface (1410) that allows UPO data to be downloaded and viewed as web pages over a local area network (1420) or the Internet.

Universal/upgrading pulse oximeter

Signal processing apparatus

The present invention involves method and apparatus for analyzing two measured signals that are modeled as containing primary and secondary portions. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, the present invention involves utilizing a transformation which evaluates a plurality of possible signal coefficients in order to find appropriate coefficients. Alternatively, the present invention involves using statistical functions or Fourier transform and windowing techniques to determine the coefficients relating to two measured signals. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Parameter compensated physiological monitor

A monitor has a primary input from which a spectral characteristic of a tissue site can be derived. The monitor also has a secondary input from which at least one parameter can be determined. A compensation relationship of the spectral characteristic, the parameter and a compensated physiological measurement is determined. A processor is configured to output the compensated physiological measurement in response to the primary input and the secondary input utilizing the compensation relationship.

Signal processing apparatus

Parameter compensated pulse oximeter

A monitor has a primary input responsive to a first property of a tissue site. An uncompensated measurement is determinable from the primary input. A parameter input is responsive to a second property associated with the tissue site, where the first property is dependent upon the second property. The monitor also has a compensation relationship of the primary input, the parameter input and a compensated measurement. A processor is configured to output a compensated measurement from the primary input and the parameter input utilizing the compensation relationship, where the compensated measurement more accurately represents the first property than the uncompensated measurement.

Medical sensor and information system

Systems and methods for determining blood oxygen saturations values using complex number encoding

The disclosure includes pulse oximetry systems and methods for determining point-by-point saturation values by encoding photoplethysmographs in the complex domain and processing the complex signals. The systems filter motion artifacts and other noise using a variety of techniques, including statistical analysis such as correlation, or phase filtering.

Improved pulse oximeter probe-off detector

An intelligent, rule-based processor (300) provides signal quality based limits to the signal strength operating region of a pulse oximeter. These limits are superimposed on the typical gain dependent signal strength limits (314). If a sensor signal appears physiologically generated, the pulse oximeter is allowed to operate with minimal signal strength, maximizing low perfusion performance. If a sensor signal is potentially due to a signal induced by a dislodged sensor, signal strength requirements are raised. Thus, signal quality limitations enhance probe off detection without significantly impacting low perfusion performance. One signal quality measure used is pulse rate density (354), which defines the percentage of time physiologically acceptable pulses are occurring. If the detected signal contains a significant portion of unacceptable pulses, the minimum required signal strength is raised proportionately. Another signal quality measure used in conjunction with pulse rate density is energy ratio (352), computed as the percentage of total energy contained in the pulse rate fundamental and associated harmonics.

Signal processing apparatus

The present invention involves method and apparatus for analyzing measured signals that are modeled as containing primary and secondary portions. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, the present invention involves utilizing a transformation which evaluates a plurality of possible signal coefficients in order to find appropriate coefficients. Alternatively, the present invention involves using statistical functions or Fourier transform and windowing techniques to determine the coefficients relating to two measured signals. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Fetal pulse oximetry sensor

A sensor provides pulse oximetry measurements from the presenting portion of a fetus. In particular, a spiral probe is designed to attach the sensor to the fetal scalp. In one sensor configuration, a light emitting region of the probe embedded in the scalp in conjunction with a light detector located at the scalp surface measures absorption from a larger volume of the scalp tissue than conventional fetal sensors. In another sensor configuration, light emitting and light collecting regions of the probe embedded in the scalp are angled with respect to the scalp surface to measure absorption from a larger volume and deeper layers of the scalp tissue than conventional fetal sensors. These sensors increase the likelihood of measuring blood volume changes occurring in larger arterioles versus smaller arterioles or capillaries, yielding a representative measurement of central arterial oxygen saturation. These sensors also reduce the calibration errors caused by a low blood fraction. Localized arteriolar flow is stimulated with heat or vasodilating substances to reduce the effects of localized oxygen consumption and to increase blood fraction. A three-wavelength sensor is utilized to detect a low blood fraction condition.

Optical sensor including information element

The method and apparatus of the present invention provides a system wherein light-emitting diodes (LEDs)(162) can be tuned within a given range by selecting their operating drive current in order to obtain a precise wavelength. The present invention further provides a manner in which to calibrate and utilize an LED probe (150), such that the shift in wavelength for a known change in drive current is a known quantity. In general, the principle of wavelength shift for current drive changes for LEDs is utilized in order to allow better calibration and added flexibility in the use of LED sensors, particularly in applications when the precise wavelength is needed in order to obtain accurate measurements. The present invention also provides a system in which it is not necessary to know precise wavelengths of LEDs where precise wavelengths were needed in the past. Finally, the present invention provides a method and apparatus for determining the operating wavelength of a light-emitting element such as a light--emitting diode.

Pulse oximeter probe-off detection system

The present invention provides a number of improvements that can be incorporated into a pulse oximeter probe to detect when a probe has become dislodged from a patient and/or to prevent a probe-off condition. A probe-off condition occurs when the optical probe becomes partially or completely dislodged from the patient, but continues to detect an AC signal within the operating region of the pulse oximeter. In one aspect, the present invention provides electrical contacts that contact the skin of a patient when the probe is properly attached. In another aspect, the present invention provides a number of louvers placed in front of the sensor's photodetector to filter out oblique light rays that do not originate from a point in front of the detector. Accordingly, if the emitter and photodetector are not properly aligned, the photodetector will not produce a signal within the valid operating range of the pulse oximeter. In accordance with a method of the present invention the pulse oximeter can sound an alarm or display a warning if it determines that the probe is not properly attached to the patient.

Signal processing apparatus and method

A signal processor which acquires a first signal, including a first desired signal portion and a first undesired signal portion, and a second signal, including a second desired signal portion and a second undesired signal portion, wherein the first and second desired signal portions are correlated. The signals may be acquired by propagating energy through a medium and measuring an attenuated signal after transmission or reflection. Alternatively, the signals may be acquired by measuring energy generated by the medium. A processor of the present invention generates a noise reference signal which is a combination of only the undesired signal portions and is correlated to both the first and second undesired signal portions. The noise reference signal is then used to remove the undesired portion of each of the first and second measured signals via an adaptive noise canceler, preferably of the joint process estimator type. The processor of the present invention may be employed in conjunction with an adaptive noise canceler in physiological monitors wherein the known properties of energy attenuation through a medium are used to determine physiological characteristics of the medium. Many physiological conditions, such as the pulse of a patient or the concentration of a constituent in a medium, can be determined from the desired portion of the signal after undesired signal portions, such as those caused by erratic motion, are removed.

Signal processing apparatus and method

A signal processor which acquires a first signal (S?a), including a first desired signal portion (Y?a) and a first undesired signal portion (n?a), and a second signal (S?b), including a second desired signal portion (Y?b) and a second undesired signal portion (n?b), wherein the first and second desired signal portions are correlated. The processor (26) of the present invention gen-erates a noise reference signal (n'(t)) which is a combination of only the undesired signal portions and is correlated to both the first and second undesired signal portions. The noise reference signal (n'(t)) is then used to remove the undesired portion of each of the first and second measured signals via an adaptive noise canceler (27), preferably of the joint process estimator type. The processor (26) may be employed in conjunction with an adaptive noise canceler (27) in physiological monitors (20) wherein the known properties of energy attenuation through a medium are used to determine physiological characteristics of the medium.

Pulse oximeter probe-off detection system

The present invention provides a number of improvements that can be incorporated into a pulse oximeter probe to detect when a probe has become dislodged from a patient and/or to prevent a probe-off condition. A probe-off condition occurs when the optical probe becomes partially or completely dislodged from the patient, but continues to detect an AC signal within the operating region of the pulse oximeter. In one aspect, the present invention provides electrical contacts that contact the skin of a patient when the probe is properly attached. In another aspect, the present invention provides a number of louvers placed in front of the sensor's photodetector to filter out oblique light rays that do not originate from a point in front of the detector. Accordingly, if the emitter and photodetector are not properly aligned, the photodetector will not produce a signal within the valid operating range of the pulse oximeter. In accordance with a method of the present invention the pulse oximeter can sound an alarm or display a warning if it determines that the probe is not properly attached to the patient.

Fetal pulse oximetry sensor

A sensor provides pulse oximetry measurements from the presenting portion of a fetus. In particular, a spiral probe is designed to attach the sensor to the fetal scalp. In one sensor configuration, a light emitting region of the probe embedded in the scalp in conjunction with a light detector located at the scalp surface measures absorption from a larger volume of the scalp tissue than conventional fetal sensors. In another sensor configuration, light emitting and light collecting regions of the probe embedded in the scalp are angled with respect to the scalp surface to measure absorption from a larger volume and deeper layers of the scalp tissue than conventional fetal sensors. These sensors increase the likelihood of measuring blood volume changes occurring in larger arterioles versus smaller arterioles or capillaries, yielding a representative measurement of central arterial oxygen saturation. These sensors also reduce the calibration errors caused by a low blood fraction. Localized arteriolar flow is stimulated with heat or vasodilating substances to reduce the effects of localized oxygen consumption and to increase blood fraction. A three-wavelength sensor is utilized to detect a low blood fraction condition.

Stereo pulse oximeter

An improved pulse oximeter provides for simultaneous, noninvasive oxygen status and photoplethysmograph measurements at both single and multiple sites. In particular, this multiple-site, multiple-parameter pulse oximeter, or "stereo pulse oximeter" (100) simultaneously measures both arterial (SPA02) and venous (SPV02) oxygen saturation at any specific site and generates a corresponding plethysmograph waveform. A corresponding computation of arterial minus venous oxygen saturation is particularly advantageous for oxygen therapy management. An active pulse-inducing mechanism having a scattering-limited drive generates a consistent pulsatile venous signal utilized for the venous blood measurements. The stereo pulse oximeter also measures arterial oxygen saturation and plethysmograph shape parameters across multiple sites.; A corresponding calculation of delta arterial saturation and comparison of plethysmograph shape parameters between multiple sites is particularly advantageous for the detection and management of persistant pulmonary hypertension in neonates (PPHN), a patent ductus arteriosis (PDA), and aortic coarctation.

Respiratory monitoring

A patient interface in accordance with one embodiment of the present invention is configured to be at least partially carried by a patient and to receive gas exhaled by the patient. The patient interface includes first and second cannula tubes each having a first end and a second end, the first ends are configured to be inserted into the nostrils of a patient, the first and second cannula tubes are configured to direct exhaled gas from the patient from the first ends to said second ends. The patient interface also includes first and second sensors positioned near the second ends, and the first and second sensors are configured to provide first and second signals based upon the gas, wherein the first and second signals are indicative of a physiological parameter of the patient. The patient interface also includes a communications link configured to provide the signal to a physiological monitor.

Multi-wavelength physiological monitor

A physiological monitor for determining blood oxygen saturation of a medical patient includes a sensor, a signal processor and a display. The sensor includes at least three light emitting diodes. Each light emitting diode is adapted to emit light of a different wavelength. The sensor also includes a detector, where the detector is adapted to receive light from the three light emitting diodes after being attenuated by tissue. The detector generates an output signal based at least in part upon the received light. The signal processor determines blood oxygen saturation based at least upon the output signal, and the display provides an indication of the blood oxygen saturation.

Medical sensor and information system

Physiological monitor

A patient monitor has multiple sensors adapted to attach to tissue sites of a living subject. The sensors generate sensor signals that are responsive to at least two wavelengths of optical radiation after attenuation by pulsatile blood within the tissue sites. A patient monitor uses the sensor signals to determine changes in constant oxygen consumption as an indication of changes in metabolism at the tissue cite.

Improved pulse oximeter probe-off detector

Dual-mode pulse oximeter

Signal processing apparatus and method

A signal processor which acquires a first signal (S?a), including a first desired signal portion (Y?a) and a first undesired signal portion (n?a), and a second signal (S?b), including a second desired signal portion (Y?b) and a second undesired signal portion (n?b), wherein the first and second desired signal portions are correlated. The processor (26) of the present invention gen-erates a noise reference signal (n'(t)) which is a combination of only the undesired signal portions and is correlated to both the first and second undesired signal portions. The noise reference signal (n'(t)) is then used to remove the undesired portion of each of the first and second measured signals via an adaptive noise canceler (27), preferably of the joint process estimator type. The processor (26) may be employed in conjunction with an adaptive noise canceler (27) in physiological monitors (20) wherein the known properties of energy attenuation through a medium are used to determine physiological characteristics of the medium.

Blood glucose monitoring system

Method and apparatus for demodulating signals in a pulse oximetry system

A method and an apparatus measure blood oxygenation in a subject. A light source is activated to cause a first emission at a first wavelength and a second emission at a second wavelength. A detector detects a composite signal indicative of an attenuation of the first and second wavelengths by tissue of a patient. The composite signal is demodulated into a first intensity signal and a second intensity signal. Blood oxygenation in the subject is determined from the first and second intensity signals. In one embodiment, demodulation is based at least in part on a period when at least one of the wavelengths is not activated. In one embodiment, a modulation of the first and second wavelengths is determined in order to avoid frequencies of ambient noise. In one embodiment, the composite signal's sampling rate is reduced before and/or after demodulation.

Stereo pulse oximeter

An improved pulse oximeter provides for simultaneous, noninvasive oxygen status and photoplethysmograph measurements at both single and multiple sites. In particular, this multiple-site, multiple-parameter pulse oximeter, or "stereo pulse oximeter" (100) simultaneously measures both arterial (SPA02) and venous (SPV02) oxygen saturation at any specific site and generates a corresponding plethysmograph waveform. A corresponding computation of arterial minus venous oxygen saturation is particularly advantageous for oxygen therapy management. An active pulse-inducing mechanism having a scattering-limited drive generates a consistent pulsatile venous signal utilized for the venous blood measurements. The stereo pulse oximeter also measures arterial oxygen saturation and plethysmograph shape parameters across multiple sites.; A corresponding calculation of delta arterial saturation and comparison of plethysmograph shape parameters between multiple sites is particularly advantageous for the detection and management of persistant pulmonary hypertension in neonates (PPHN), a patent ductus arteriosis (PDA), and aortic coarctation.

Signal processing apparatus and method

A signal processor which acquires a first signal, including a first desired signal portion and a first undesired signal portion, and a second signal, including a second desired signal portion and a second undesired signal portion, wherein the first and second desired signal portions are correlated. The signals may be acquired by propagating energy through a medium and measuring an attenuated signal after transmission or reflection. Alternatively, the signals may be acquired by measuring energy generated by the medium. A processor of the present invention generates a noise reference signal which is a combination of only the undesired signal portions and is correlated to both the first and second undesired signal portions. The noise reference signal is then used to remove the undesired portion of each of the first and second measured signals via an adaptive noise canceler, preferably of the joint process estimator type. The processor of the present invention may be employed in conjunction with an adaptive noise canceler in physiological monitors wherein the known properties of energy attenuation through a medium are used to determine physiological characteristics of the medium. Many physiological conditions, such as the pulse of a patient or the concentration of a constituent in a medium, can be determined from the desired portion of the signal after undesired signal portions, such as those caused by erratic motion, are removed.

Multiple wavelength sensor emitters

Systems and methods for acquiring calibration data usable in a pulse oximeter

The present disclosure includes a pulse oximeter attachment having an accessible memory. In one embodiment, the pulse oximeter attachment stores calibration data, such as, for example, calibration data associated with a type of a sensor, a calibration curve, or the like. The calibration data is used to calculate physiological parameters of pulsing blood.

Plethysmograph pulse recognition processor

An intelligent, rule-based processor provides recognition of individual pulses in a pulse oximeter-derived photo-plethysmograph waveform. Pulse recognition occurs in two stages. The first stage identifies candidate pulses in the plethysmograph waveform. The candidate pulse stage identifies points in the waveform representing peaks and valleys corresponding to an idealized triangular wave model of the waveform pulses. At this stage, waveform features that do not correspond to this model are removed, including the characteristic dicrotic notch. The second stage applies a plethysmograph model to the candidate pulses and decides which pulses satisfies this model. This is done by first calculating certain pulse features and then applying different checks to identify physiologically acceptable features. Various statistics can then be derived from the resulting pulse information, including the period and signal strength of each pulse and pulse density, which is the ratio of the analyzed waveform segment that has been classified as physiologically acceptable.