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WO2008039195A1 - Procédé et appareil pour indexer une amplitude de pouls - Google Patents

Procédé et appareil pour indexer une amplitude de pouls Download PDF

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Publication number
WO2008039195A1
WO2008039195A1 PCT/US2006/037914 US2006037914W WO2008039195A1 WO 2008039195 A1 WO2008039195 A1 WO 2008039195A1 US 2006037914 W US2006037914 W US 2006037914W WO 2008039195 A1 WO2008039195 A1 WO 2008039195A1
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WIPO (PCT)
Prior art keywords
pulse amplitude
pulse
amplitude
monitored
mathematical combination
Prior art date
Application number
PCT/US2006/037914
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English (en)
Inventor
Bernhard B. Sterling
Alexander K. Mills
Original Assignee
Woolsthorpe Technologies, Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by Woolsthorpe Technologies, Llc filed Critical Woolsthorpe Technologies, Llc
Priority to JP2009530316A priority Critical patent/JP2010504803A/ja
Priority to EP06804239A priority patent/EP2073694A4/fr
Priority to PCT/US2006/037914 priority patent/WO2008039195A1/fr
Publication of WO2008039195A1 publication Critical patent/WO2008039195A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue
    • A61B5/1495—Calibrating or testing of in-vivo probes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
    • A61B2560/02—Operational features
    • A61B2560/0223—Operational features of calibration, e.g. protocols for calibrating sensors

Definitions

  • the present invention relates to the field of pulse oximetry. More specifically, the invention relates to a method and apparatus for improving the accuracy of pulse oximetry monitoring.
  • Pulse oximetry provides critical information regarding the cardiorespiratory function of a patient.
  • Oximeters continually monitor blood flow characteristics including, but not limited, to blood oxygen saturation of hemoglobin in arterial blood, the volume of individual blood pulsations supplying the flesh and the rate of blood pulsations corresponding to each heartbeat of the patient.
  • Illustrative are the apparatus described in U.S. Pat. Nos. 5,193,543; 5,448,991; 4,407,290; and 3,704,706.
  • a pulse oximeter passes light through human or animal body tissue where blood perfuses the tissue, such as a finger, an ear, the nasal septum or the scalp, and photoelectrically senses the absorption of light in the tissue. The amount of light absorbed is then used to calculate the amount of oxyhemoglobin and estimate arterial oxygen saturation.
  • two lights having discrete frequencies in the range of about 650- 670 nm in the red range and about 800-1000 nm in the infrared range are typically passed through the tissue. If blood saturation is constant, variations in absorbance are caused by changes in the amount of blood present in the light path, assumed to be primarily due to arterial blood volume variations corresponding to the arterial pulse. Further, because absorbance of oxyhemoglobin differs for light at the two wavelengths, a ratio of change in absorbance of red to change in absorbance of infrared light can be used to measure oxyhemoglobin percentage.
  • the signal produced by measuring the light absorption comprises AC and DC components.
  • the AC portion corresponds to varying absorption resulting from pulsatile changes in arterial blood volume while the DC portion is the base optical transmittance that primarily corresponds to tissue, venous blood, and capillary blood absorption.
  • the AC portion of the signal contains a component that is a waveform representative of the patient's blood gas saturation. This component is referred to as a "plethysmography wave or waveform" (see curve P in FIG. 1).
  • the ratio of absorbance at the two wavelengths that is attributed to the pulsatile component can be correlated to known saturation values to calibrate the obtained oximetry data.
  • conventional pulse oximetry methods utilize a ratio of logarithms of the amplitude of the AC signal, i.e. the pulse amplitude, to determine this ratio.
  • the saturation measurements are conventionally determined using the amplitude at maximum and minimum values in the plethysmography wave to improve the signal to noise ratio.
  • a difficulty associated with pulse oximetry is that the relative strength of the AC signal as compared to the base optical transmittance has been observed to vary between patients by more than two orders of magnitude. For example, maximal pulse amplitudes range from less than 0.1% to over 10% of measured base optical transmittance among different patients.
  • pulse amplitude variation Some aspects of the noted pulse amplitude variation are sensor and sensor attachment related. However, the majority of variations originate from the physical extension of the small arterial blood vessels during the pulse pressure wave which is determined by cardiac contractility and arterial vessel wall distensibility. Thus, the relative strength of the pulse amplitude signal is a patient characteristic and, for the purpose of oximetry data collection, is not amenable to being optimized.
  • the ratio of logarithms that corresponds to the ratio of absorbance is non-linearly dependent on the amplitude of the pulse signal. Accordingly, the wide variations in relative pulse amplitude strength between patients can lead to inherent inaccuracies in the determination of blood oxygen saturation. No conventional methods of pulse oximetry have recognized and compensated for the errors in oximetry data attributed to variability in pulse amplitudes.
  • Yet another object of the invention is to provide calibration data relating the ratio of logarithms to oxygen saturation at a plurality of pulse amplitudes.
  • the invention includes a device for monitoring a physiological characteristic of a patient's blood having first and second radiation emitters that emit light at first and second wavelengths, a radiation detector configured to receive light at the first and second wavelengths after absorbance through the patient's blood and provide first and second intensity signals corresponding to the first and second received wavelengths, and a controller for computing the physiological characteristic of the patient's blood by determining a pulse amplitude associated with the first and second intensity signals and indexing a monitored mathematical combination of the first and second intensity signals to the determined pulse amplitude, wherein the monitored mathematical combination is related to the physiological characteristic and calculated from the first and second intensity signals.
  • the device is configured to determine arterial oxygen saturation.
  • the first wavelength is in the range of approximately 650-670 nm.
  • the second wavelength is in the range of 800-1000 nm.
  • the mathematical combination is a ratio of the first and second intensity signals.
  • the value is indexed to a stored calibration dataset relating the ratio to oxygen saturation at a specific pulse amplitude.
  • a plurality of stored calibration datasets are provided that relate the ratio to oxygen saturation at a plurality of pulse amplitudes in the range of approximately 0.1% to 10%.
  • the stored calibration datasets comprise a plurality of datasets at pulse amplitudes in the range of approximately 0.1% to 1%.
  • the controller determines the pulse amplitude from the second intensity signal.
  • the controller determines the pulse amplitude in reference to a first amplitude minimum in the second intensity signal.
  • the controller determines the pulse amplitude in reference to a first and a second amplitude minimum in the second intensity signal.
  • the indexing occurs at a plurality of pulse amplitudes in a given pulse.
  • the monitored mathematical combination is calculated from an average of a plurality of pulses.
  • the monitored mathematical combination is indexed to a maximum determined pulse amplitude.
  • the invention also comprises a method for processing signals reflecting a physiological characteristic of a patient's blood, comprising the steps of (i) coupling an oximeter sensor arrangement to a tissue region of the patient; (ii) passing first and second lights through the patient's tissue region, wherein the first light is substantially in a red light range and the second light is substantially in an infrared light range; (iii) detecting the first and second lights absorbed by the tissue region and providing a first and second intensity signal corresponding to the absorbed first and second lights; (iv) determining a pulse amplitude associated with the first and second intensity signals; (v) calculating a monitored mathematical combination of the first and second intensity signals, wherein the monitored mathematical combination is related to the physiological characteristic; and (vi) indexing the monitored mathematical combination to the determined pulse amplitude.
  • the physiological characteristic determined is arterial oxygen saturation.
  • the monitored mathematical combination is a ratio of the first and second intensity signals.
  • the step of indexing comprises relating the ratio to a stored calibration dataset.
  • a plurality of stored calibration datasets corresponding to pulse amplitudes in the range of approximately 0.1% to 10% are used.
  • a plurality of stored calibration datasets corresponding to pulse amplitudes in the range of approximately 0.1% to 1% are used.
  • the pulse amplitude is determined from the second intensity signal.
  • the pulse amplitude is determined in reference to a first amplitude minimum in the second intensity signal.
  • the pulse amplitude is determined in reference to a first and a second amplitude minimum in the second intensity signal.
  • the step of indexing is performed a plurality of times within a given pulse.
  • the step of calculating the monitored mathematical combination comprises determining an average of a plurality of pulses.
  • the step of indexing the monitored mathematical combination comprises indexing the value to a maximum determined pulse amplitude.
  • the invention comprises a method for determining a subject's arterial oxygen saturation comprising the steps of (i) determining arterial oxygen saturation as a function of a mathematical combination of two optical signals at each of a plurality of specific pulse amplitudes, (ii) storing the arterial oxygen saturation functions, (iii) obtaining oximetry data from a subject, (iv) determining the subject's pulse amplitude, (v) monitoring a mathematical combination of two optical signal obtained from the oximetry data, (vi) selecting a stored arterial oxygen saturation function having the closest pulse amplitude to the determined pulse amplitude, and (vii) determining the subject's arterial oxygen saturation from the monitored mathematical combination and the stored arterial oxygen saturation function having the closest pulse amplitude.
  • the noted method further comprises the step of interpolating the stored arterial oxygen function having the closest amplitude to the determined pulse amplitude to more closely correspond to the measured mathematical combination.
  • FIGURE 1 is a graphical illustration of an r-wave portion of an electrocardiogram waveform and the related plethysmographic waveform;
  • FIGURE 2 is a schematic illustration of a pulse oximeter apparatus, according to the invention.
  • FIGURES 3 and 4 are graphical illustrations of red and infrared optical signals taken from independent sensors
  • FIGURES 5 and 6 are graphical illustrations of pulse amplitude as a function of ratio of logarithms taken from independent sensors for a single pulse at relatively low oxygen saturation, according to the invention
  • FIGURES 7 and 8 are graphical illustrations of pulse amplitude as a function of the ratio of logarithms for a single pulse obtained from different patients at relatively high oxygen saturation, according to the invention.
  • FIGURE 9 is a graphical illustration comparing pulse amplitude indexed and conventional ratio of logarithms as a function of oxygen saturation, according to the invention.
  • signal is meant to mean and include an analog electrical waveform or a digital representation thereof, which is collected from a biological or physiological sensor.
  • dataset is meant to mean and include data relating a mathematical combination of detected optical signals to saturation at a specific pulse amplitude.
  • each dataset can comprise the calibration relating the ratio of logarithms to arterial oxygen saturation for a given pulse amplitude.
  • a plurality of datasets are used, each at different pulse amplitude, so that a dataset having a pulse amplitude that closely matches a given patient's pulse amplitude can be used.
  • patient and “subject”, as used herein, mean and include humans and animals.
  • the present invention substantially increases the accuracy of conventional pulse oximetry systems, apparatus and techniques.
  • the method and apparatus for determining a physiological characteristic comprises detecting the intensity of light following tissue absorption at two wavelengths, estimating the pulse amplitude and indexing a calculated physiological characteristic to the estimated pulse amplitude.
  • pulse amplitude indexing links a measured ratio of logarithms obtained from a patient having a specific pulse amplitude to stored calibration data that relates the ratio of logarithms to oxygen saturation at a predetermined pulse amplitude. More accurate oximetry determinations can be made by using calibration data at a pulse amplitude that closely matches the pulse amplitude of the patient.
  • pulse amplitude indexing is performed on a pulse average. More preferably, pulse amplitude indexing is performed during every pulse for optimal patient management.
  • FIG. 1 there is shown a graphical illustration of an "r-wave” portion of an electrocardiogram (ECG) waveform (designated “r”) and the related plethysmography waveform (designated “p”).
  • ECG waveform comprises a complex waveform having several components that correspond to electrical heart activity.
  • the QRS component relates to ventricular heart contraction.
  • the r-wave portion of the QRS component is typically the steepest wave therein, having the largest amplitude and slope, and may be used for indicating the onset of cardiovascular activity.
  • the arterial blood pulse flows mechanically and its appearance in any part of the body typically follows the R wave of the electrical heart activity by a determinable period of time that remains essentially constant for a given patient. See, e.g., Goodlin et al., "Systolic Time Intervals in the Fetus and Neonate, Obstetrics and Gynecology", Vol. 39, No. 2, (February 1972) and U.S. Pat. No. 3,734,086.
  • FIG. 2 there is shown a schematic illustration of one embodiment of a pulse oximeter apparatus 5 that can be employed within the scope of the invention.
  • conventional pulse oximetry methods and apparatus typically employ two lights; a first light having a discrete wavelength in the range of approximately 650-670 nm in the red range and a second light having a discrete wavelength in the range of approximately 800-1000 nm.
  • a suitable red LED emits light at approximately 660 nm and a suitable infrared LED emits light at approximately 880 nm.
  • the lights are typically directed through a finger 4 via emitters 12, 14 and detected by a photo detector 16, such as a square photodiode with an area of 49 mm 2 .
  • Emitters 12 and 14 are driven by drive circuitry 18, which is in turn governed by control signal circuitry 20.
  • Detector 16 is in communication with amplifier 22.
  • the LEDs are activated at a rate of 8,000 times per second (8 kHz) per cycle, with a cycle comprising red on, quiescent, IR on, quiescent.
  • the total cycle time is 125 microseconds and the LEDs are active for approximately 41.25 microseconds at a time.
  • the photo detector 16 provides an output signal that is transmitted to an amplifier 22.
  • the amplified signal from amplifier 22 is then transmitted to demodulator 24, which is also synched to control signal circuitry 20.
  • the output signal from the demodulator 24 would be a time multiplexed signal comprising (i) a background signal, (ii) the red light range signal and (iii) the infrared light range signal.
  • the demodulator 24 which is employed in most pulse oximeter systems, removes any common mode signals present and splits the time multiplexed signal into two (2) channels, one representing the red voltage (or optical) signal and the other representing the infrared voltage (or optical) signal.
  • the signal from the demodulator 24 is transmitted to analog-digital converter (ADC) 26.
  • ADC analog-digital converter
  • DSP signal processor
  • ADC 26 converts the analog signals into 16-bit signed digital signals at a rate of 8 IcHz.
  • DSP 28 preferably notch filters the data at 40 Hz to eliminate power line frequency noise limit high frequency noise from other sources.
  • the DSP parses each data stream by a factor of 4 to give two digital data streams at a rate of 2 IcHz.
  • the system electronics are configured so that emitters 12 and 14 are driven with a variable gain to produce an AC signal (corresponding to the photoplethysmograph pulse waveform) riding on a larger DC signal.
  • the range of values corresponding to the AC signal represent the pulse amplitude at various points during a pulse wave.
  • the current supplied to the emitters is feedback driven to produce a constant DC signal of approximately 1.25 V, for both the red and infrared signals. The actual DC value is reported continuously.
  • the magnitude of the AC signals is computed relative to the DC signal.
  • the AC component is the signal that is given to the ADC 26 and converted to digital, with the DC signal treated as the "zero point".
  • the noted signals optionally can be subjected to processing steps to improve their quality.
  • the signals can be processed as described in Co-Pending U.S. Patent Application Serial No.
  • the red and infrared signals are corrected by applying a residual corresponding to noise that is derived from an average of the red and infrared signals as multiplied by a residual factor subtracted from a difference between the red and infrared signals.
  • this step is not intended to be limiting and is not required to practice the invention.
  • the AC signals can also be processed by any other suitable method, including processes related to obtaining the averages of many single pulses or limiting the evaluation to the maximal amplitude of the each pulse wave signal.
  • the ratio of logarithms of the amplitude of the red and infrared signals is indexed to the pulse amplitude.
  • FIGS. 3 and 4 show data collected by during a single pulse, from sensors A and B. Both outputs of the sensors are then converted to amplitudes in mV, A 1R and A R e d - The data shown has also been corrected as described in the above-referenced patent application.
  • maximal and minimal amplitudes of the data streams are determined using a comparator on a continuous moving average of 50 samples.
  • pulse amplitudes are first determined at all time points, including the maximal pulse amplitude, as the difference between the amplitude at any time point and a reference minimum, relative to the DC value.
  • the maximum amplitude shown in FIG. 3 occurs at approximately time point 150.
  • the reference minimum is the first minimum in the signal, which is shown in FIG. 3 as occurring at approximately time point 125.
  • a different reference minimum can be established, for example, a minimum derived from the first and second minimums. As shown in FIG. 3, the second minimum occurs at approximately time point 290.
  • the best estimate of pulse amplitude in percent is calculated from the infrared signal because it is less dependent on blood oxygen saturation than the red signal.
  • the infrared amplitudes are then corrected at all time points during a selected pulse wave by applying the following empirically determined linear correction, wherein Sat is the saturation in percent:
  • PA 100 * (PA max /1.25) + ((PA max /1.25) * (-5.58 + (8.17 * Sat))/100))
  • the resulting PA values are percentages in the range of approximately 0.1 and 10 for most pulses. As one having skill in the art will appreciate, the factors used in the correction can be adjusted as necessary.
  • determining the pulse amplitude provides additional information for substantially improving the accuracy oximetry determinations from the monitored ratio of logarithms of the same patient or between different patients.
  • the accuracy of the ratio of logarithms, or any other mathematical combination of the fundamental oximetry signals such as the ratio of the red to the infrared signals, or the ratio of red to infrared signals after normalizing for specific DC values, can be improved by indexing it to one or more pulse amplitudes for every pulse.
  • pulse amplitude indexing is achieved by applying patient data at different pulse amplitudes from different patients over a wide saturation range to create a calibration dataset relating the ratio of logarithms to saturation for any desired pulse amplitude over the entire expected range of less than 0.1% to over 10%.
  • a calibration data set having a resolution of 0.1 % is used.
  • the accuracy of determinations can be improved by increasing the number of data sets stored in the oximeter to provide greater resolution for indexing.
  • the ratio of logarithms is a useful parameter for conversion to saturation and calibration of oximeters.
  • the simplicity is due in part by the engineering design of driving the LED intensity until a given baseline optical transmittance (DC) is reached.
  • AC/DC is the ratio of transmittances but since the DC signal is configured to be constant, the ratio of the logarithms is equivalent to the ratio of absorbances.
  • the ratio of logarithms is the principal measurement parameter that relates to reference saturation percent for calibrating pulse oximeters. It is calculated from the amplitudes AIR and A Red •
  • the first step is to bring the amplitudes of the red and infrared signals A R e dM i n and Ai RM i n , which represent the equivalent of optical transmittance to zero. This operation can be performed at either the first minimum or at the average of the first and the second minimum.
  • the ratio R is then calculated as the absolute logarithm of the zeroed red amplitude over the absolute logarithm of the zeroed infrared amplitudes:
  • the resulting ratio of logarithms of the absorbances is analyzed as a function of pulse amplitude during an average or, more preferably, during a single pulse, to derive a pulse amplitude indexed ratio of logarithms which can be calibrated to CO-oximetry reference data in a conventional manner.
  • FIGS. 5-8 Exemplary data indicating relationship between pulse amplitude and the ratio of logarithms is shown in FIGS. 5-8.
  • FIGS. 5 and 6 relate the calculated PA to the ratio of logarithms in a single selected pulse at a known saturation from two independent sensors. The data demonstrate that PA substantially influences the ratio of logarithms as evidenced by the changing ratio values at different pulse amplitudes, despite the constant saturation.
  • FIGS. 7 and 8 compare the ratio of logarithms between two patients exhibiting varying ranges of pulse amplitude at similar saturations.
  • the data represented in FIG. 7 was collected from a patient that exhibited a relatively weak pulse amplitude signal as compared to the baseline optical transmittance, less than 0.1 %.
  • the data in FIG. 8 was collected from a patient that exhibited a relatively strong pulse amplitude signal, greater than 4 %.
  • data such as that illustrated in FIGS. 5-8 are collected from individual patients at different saturations and different pulse amplitudes.
  • the monitored ratio of logarithms from a patient is indexed to the calculated PA at each timepoint in the plethysmograph wave to compensate for the pulse amplitude dependency.
  • the calculations described above are used to provide a method for determining arterial oxygen saturation with pulse amplitude indexing. Specifically, arterial oxygen saturation as a function of the ratio of logarithms is determined at each of a plurality of specific pulse amplitudes over a desired range and stored.
  • Oximetry data is then obtained from a subject and the subject's pulse amplitude is determined.
  • a monitored ratio of logarithms for the subject is calculated from the obtained data.
  • a stored arterial oxygen saturation function at a pulse amplitude that closely matches the subject's pulse amplitude is selected.
  • the monitored ratio of logarithms is used with the selected arterial oxygen saturation function to determine the arterial oxygen saturation of the subject.
  • the stored arterial oxygen saturation function having the closest pulse amplitude can be interpolated to more closely match the monitored ratio of logarithms.
  • the stored saturation data then can be used with pulse oximetry monitoring to determine arterial oxygen saturation.
  • the monitored IR signal is corrected as described above using an empirically derived formula.
  • the voltage ratio and saturation factor then can be combined to calculate the pulse amplitude:
  • PA ( ( saturation factor * voltage ratio / 100 ) + voltage ratio ) * 100
  • the calculated pulse amplitude and the ratio of logarithms as monitored can be used to make a best fit approximation of saturation from the stored arterial saturation data using standard techniques, such as a least-squares estimate.
  • the array datasets can be interpolated to provide precise calculations of saturation for any pulse amplitude and any ratio of logarithms.
  • an alternate mathematical combination of the red and infrared signals can be used in place of the ratio of logarithms.
  • a study comparing oximetry determinations using the pulse amplitude indexed ratio of logarithms as described above to non-indexed values was performed with 8 adult volunteers.
  • a catheter was placed into a radial artery of each subject.
  • a Nellcor N-200 pulse oximeter was used as a reference device, and also for clinically monitoring the subject.
  • Each subject was given varying inspired concentrations of oxygen in order to produce arterial hemoglobin oxygen saturations in the approximate range of 70-100%.
  • any amplitude can be chosen for which reference data are available.
  • the highest pulse amplitude available for each pulse is employed in order to maximize the signal to noise ratio.
  • the calibration curve also has a steeper slope, which results in improved resolution of the measured saturation parameter.
  • indexing data for as many saturations and pulse amplitudes at a resolution of less than 1% pulse amplitude, such as 0.1%, as practical.

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Abstract

La présente invention comprend un procédé et un appareil destinés à déterminer une caractéristique physiologique en détectant l'intensité de la lumière après absorption par le tissu à deux longueurs d'onde, en estimant l'amplitude de pouls et en indexant une caractéristique physiologique calculée sur l'amplitude de pouls estimée. Dans un mode de réalisation, le rapport des logarithmes de l'amplitude des signaux d'absorbance est indexé sur l'amplitude de pouls afin d'améliorer la précision de la saturation artérielle en oxygène déterminée par un oxymètre de pouls.
PCT/US2006/037914 2006-09-27 2006-09-27 Procédé et appareil pour indexer une amplitude de pouls WO2008039195A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2009530316A JP2010504803A (ja) 2006-09-27 2006-09-27 パルスの振幅のインデックス付け方法及び装置
EP06804239A EP2073694A4 (fr) 2006-09-27 2006-09-27 Procédé et appareil pour indexer une amplitude de pouls
PCT/US2006/037914 WO2008039195A1 (fr) 2006-09-27 2006-09-27 Procédé et appareil pour indexer une amplitude de pouls

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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009142853A1 (fr) * 2008-05-22 2009-11-26 The Curators Of The University Of Missouri Procédé et système de détection optique non invasif du glucose sanguin utilisant l’analyse de données spectrales
WO2010004554A1 (fr) * 2008-07-06 2010-01-14 Or-Nim Medical Ltd. Procédé et système permettant une surveillance non effractive du flux d’un fluide dans un sujet
US7809418B2 (en) 2007-10-04 2010-10-05 The Curators Of The University Of Missouri Optical device components
US7961304B2 (en) 2007-09-13 2011-06-14 The Curators Of The University Of Missouri Optical device components
US7961305B2 (en) 2007-10-23 2011-06-14 The Curators Of The University Of Missouri Optical device components
US8336391B2 (en) 2008-07-06 2012-12-25 Or-Nim Medical Ltd. Method and system for non-invasively monitoring fluid flow in a subject
US8509869B2 (en) 2009-05-15 2013-08-13 Covidien Lp Method and apparatus for detecting and analyzing variations in a physiologic parameter
US8552359B2 (en) 2009-04-01 2013-10-08 The Curators of the Univesity of Missouri Optical spectroscopy device for non-invasive blood glucose detection and associated method of use
US8571623B2 (en) 2007-03-09 2013-10-29 Covidien Lp System and method for detection of venous pulsation
US9027412B2 (en) 2008-07-06 2015-05-12 Or-Nim Medical Ltd. Method and system for non-invasively monitoring fluid flow in a subject
US9066660B2 (en) 2009-09-29 2015-06-30 Nellcor Puritan Bennett Ireland Systems and methods for high-pass filtering a photoplethysmograph signal
US9237850B2 (en) 2007-06-04 2016-01-19 Or-Nim Medical Ltd. System and method for noninvasively monitoring conditions of a subject
WO2016210282A1 (fr) * 2015-06-25 2016-12-29 Fresenius Medical Care Holdings, Inc. Système de mesure différentielle de lumière directe
US9560994B2 (en) 2008-03-26 2017-02-07 Covidien Lp Pulse oximeter with adaptive power conservation
US10542919B2 (en) 2008-03-25 2020-01-28 St. Louis Medical Devices, Inc. Method and system for non-invasive blood glucose detection utilizing spectral data of one or more components other than glucose

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6421549B1 (en) * 1999-07-14 2002-07-16 Providence Health System-Oregon Adaptive calibration pulsed oximetry method and device
US6711425B1 (en) * 2002-05-28 2004-03-23 Ob Scientific, Inc. Pulse oximeter with calibration stabilization

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6882874B2 (en) * 2002-02-15 2005-04-19 Datex-Ohmeda, Inc. Compensation of human variability in pulse oximetry
US7194293B2 (en) * 2004-03-08 2007-03-20 Nellcor Puritan Bennett Incorporated Selection of ensemble averaging weights for a pulse oximeter based on signal quality metrics

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6421549B1 (en) * 1999-07-14 2002-07-16 Providence Health System-Oregon Adaptive calibration pulsed oximetry method and device
US6711425B1 (en) * 2002-05-28 2004-03-23 Ob Scientific, Inc. Pulse oximeter with calibration stabilization

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP2073694A4 *

Cited By (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8571623B2 (en) 2007-03-09 2013-10-29 Covidien Lp System and method for detection of venous pulsation
US9237850B2 (en) 2007-06-04 2016-01-19 Or-Nim Medical Ltd. System and method for noninvasively monitoring conditions of a subject
US7961304B2 (en) 2007-09-13 2011-06-14 The Curators Of The University Of Missouri Optical device components
US7809418B2 (en) 2007-10-04 2010-10-05 The Curators Of The University Of Missouri Optical device components
US7961305B2 (en) 2007-10-23 2011-06-14 The Curators Of The University Of Missouri Optical device components
US11147482B2 (en) 2008-03-25 2021-10-19 St. Louis Medical Devices, Inc. Method and system for non-invasive blood glucose measurement using signal change of the non-glucose components induced by the presence of glucose
US10542919B2 (en) 2008-03-25 2020-01-28 St. Louis Medical Devices, Inc. Method and system for non-invasive blood glucose detection utilizing spectral data of one or more components other than glucose
US9560994B2 (en) 2008-03-26 2017-02-07 Covidien Lp Pulse oximeter with adaptive power conservation
US9579049B2 (en) 2008-05-22 2017-02-28 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US9629576B2 (en) 2008-05-22 2017-04-25 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US10959650B2 (en) 2008-05-22 2021-03-30 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US11986291B2 (en) 2008-05-22 2024-05-21 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US12036019B2 (en) 2008-05-22 2024-07-16 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US11553859B2 (en) 2008-05-22 2023-01-17 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
WO2009142853A1 (fr) * 2008-05-22 2009-11-26 The Curators Of The University Of Missouri Procédé et système de détection optique non invasif du glucose sanguin utilisant l’analyse de données spectrales
US9566024B2 (en) 2008-05-22 2017-02-14 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US11076781B2 (en) 2008-05-22 2021-08-03 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US8340738B2 (en) 2008-05-22 2012-12-25 The Curators Of The University Of Missouri Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US10973442B2 (en) 2008-05-22 2021-04-13 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US9788764B2 (en) 2008-05-22 2017-10-17 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US9814415B2 (en) 2008-05-22 2017-11-14 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US9877670B2 (en) 2008-05-22 2018-01-30 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US10070809B2 (en) 2008-05-22 2018-09-11 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US10080515B2 (en) 2008-05-22 2018-09-25 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US8336391B2 (en) 2008-07-06 2012-12-25 Or-Nim Medical Ltd. Method and system for non-invasively monitoring fluid flow in a subject
WO2010004554A1 (fr) * 2008-07-06 2010-01-14 Or-Nim Medical Ltd. Procédé et système permettant une surveillance non effractive du flux d’un fluide dans un sujet
US9027412B2 (en) 2008-07-06 2015-05-12 Or-Nim Medical Ltd. Method and system for non-invasively monitoring fluid flow in a subject
US8552359B2 (en) 2009-04-01 2013-10-08 The Curators of the Univesity of Missouri Optical spectroscopy device for non-invasive blood glucose detection and associated method of use
US8509869B2 (en) 2009-05-15 2013-08-13 Covidien Lp Method and apparatus for detecting and analyzing variations in a physiologic parameter
US9649071B2 (en) 2009-09-29 2017-05-16 Nellcor Puritan Bennett Ireland Systems and methods for high-pass filtering a photoplethysmograph signal
US9066660B2 (en) 2009-09-29 2015-06-30 Nellcor Puritan Bennett Ireland Systems and methods for high-pass filtering a photoplethysmograph signal
US10426387B2 (en) 2015-06-25 2019-10-01 Fresenius Medical Care Holdings, Inc. Direct light differential measurement system
US11241176B2 (en) 2015-06-25 2022-02-08 Fresenius Medical Care Holdings, Inc. Direct light differential measurement system with increased noise immunity
WO2016210282A1 (fr) * 2015-06-25 2016-12-29 Fresenius Medical Care Holdings, Inc. Système de mesure différentielle de lumière directe
US12114973B2 (en) 2015-06-25 2024-10-15 Fresenius Medical Care Holdings, Inc. Direct light differential measurement system

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