Apparatus and method for monitoring pressure related changes in the extra-thoracic arterial circulatory system
First Claim
1. A pulmonary monitoring system comprising:
- sensing means for detecting a physiological characteristic of a patient associated with pressure changes in such a patient'"'"'s extra-thoracic arterial circulation and for outputting a first signal indicative of such pressure changes wherein the sensing means comprises a photoemitter adapted to direct light through a portion of the patient, and a photodetector adapted to receive light after having been directed through such a patient, and wherein the photoemitter emits light at a wavelength that is relatively insensitive to an oxygen saturation level of such a patient while relatively sensitive to changes in path length between the photoemitter and photodetector; and
processing means for producing a pulmonary pressure signal as a measure of such a patient'"'"'s intra-thoracic pressure due to respiration by isolating breath related pressure variations in the first signal.
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Accused Products
Abstract
A method and apparatus for monitoring changes in the intra-thoracic pressure of a patient due to the patient'"'"'s respiratory activity or volumetric changes in the extra-thoracic arterial circulatory system due to cardiac function based on the changes in pressure in the patient'"'"'s extra-thoracic arterial circulatory system as measured by a plethysmography sensor, such as an photoplethysmograph. A frequency spectrum is generated for the plethysmograph signal and the frequencies of interest is isolated from the frequency spectrum by setting appropriate cutoff frequencies for the frequency spectrum. This isolated frequency is used to filter the plethysmograph signal to provide a signal indicative of the patient'"'"'s respiratory activity or cardiac function. For corrections for breathing frequency roll-off and deviations of the I:E ratio from 1:1.
98 Citations
48 Claims
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1. A pulmonary monitoring system comprising:
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sensing means for detecting a physiological characteristic of a patient associated with pressure changes in such a patient'"'"'s extra-thoracic arterial circulation and for outputting a first signal indicative of such pressure changes wherein the sensing means comprises a photoemitter adapted to direct light through a portion of the patient, and a photodetector adapted to receive light after having been directed through such a patient, and wherein the photoemitter emits light at a wavelength that is relatively insensitive to an oxygen saturation level of such a patient while relatively sensitive to changes in path length between the photoemitter and photodetector; and processing means for producing a pulmonary pressure signal as a measure of such a patient'"'"'s intra-thoracic pressure due to respiration by isolating breath related pressure variations in the first signal. - View Dependent Claims (2, 3, 4, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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5. A pulmonary monitoring system comprising:
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sensing means for detecting a physiological characteristic of a patient associated with pressure changes in such a patient'"'"'s extra-thoracic arterial circulation and for outputting a first signal indicative of such pressure changes; and processing means for producing a pulmonary pressure signal as a measure of such a patient'"'"'s intra-thoracic pressure due to respiration by isolating breath related pressure variations in the first signal, and wherein the processing means comprises; frequency analyzing means for determining frequency components of the first signal; respiratory rate frequency component identifying means for identifying a respiratory rate frequency component (fRR) from the frequency components of the first signal; and dynamic filtering means for filtering the first signal based on the respiratory rate frequency component fRR so as to isolate the respiratory rate frequency component fRR from the first signal to produce the pulmonary pressure signal. - View Dependent Claims (6, 7, 8, 9)
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10. A pulmonary monitoring system comprising:
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sensing means for detecting a physiological characteristic of a patient associated with pressure changes in such a patient'"'"'s extra-thoracic arterial circulation and for outputting a first signal indicative of such pressure changes; and processing means for producing a pulmonary pressure signal as a measure of such a patient'"'"'s intra-thoracic pressure due to respiration by isolating breath related pressure variations in the first signal, and wherein the processing means comprises; frequency analyzing means for determining frequency components of the first signal; heart rate frequency component identifying means for identifying a heart rate frequency component fHR from the frequency components of the first signal; and dynamic filtering means for filtering the physiologic signal based on the heart rate frequency component fHR so as to remove the heart rate frequency component fHR from the physiologic signal, thereby isolating a respiratory rate frequency component fRR of the first signal to produce the pulmonary pressure signal. - View Dependent Claims (11, 12)
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13. A pulmonary monitoring system comprising:
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sensing means for detecting a physiological characteristic of a patient associated with pressure changes in such a patient'"'"'s extra-thoracic arterial circulation and for outputting a first signal indicative of such pressure changes; and processing means for producing a pulmonary pressure signal as a measure of such a patient'"'"'s intra-thoracic pressure due to respiration by isolating breath related pressure variations in the first signal, and wherein the processing means comprises; frequency analyzing means for determining frequency components of the first signal, including a respiratory rate frequency component fRR and a heart rate frequency component fHR; respiratory rate frequency component fRR identifying means for identifying the respiratory rate frequency component fRR from the frequency components of the first signal; heart rate frequency component fHR identifying means for identifying the heart rate frequency component fHR from the frequency components of the first signal; and dynamic filtering means for filtering the first signal based on the respiratory rate frequency component fRR and the heart rate frequency component fHR so as to isolate the respiratory rate frequency component fRR from the first signal to produce the pulmonary pressure signal. - View Dependent Claims (14, 15)
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25. A pulmonary monitoring method comprising:
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(a) providing a pulmonary monitoring system including a light emitter and light receiver; (b) using the pulmonary monitoring system to (a) detect a physiological characteristic of a patient associated with pressure changes in such a patient'"'"'s extra-thoracic arterial circulation and (b) output a first signal indicative of such pressure changes, wherein detecting a physiological characteristic of a patient comprises; (1) passing light through a portion of the patient using the light emitter, and (2) receiving light using the light receiver after having been transmitted through such a patient, wherein the light has a wavelength that is relatively insensitive to an oxygen saturation level of such a patient while relatively sensitive to changes in path length between a photoemitter and photoreceiver; (c) producing, using a controller, a pulmonary pressure signal as a measure of such a patient'"'"'s intra-thoracic pressure due to respiration by isolating breath related pressure variations in the first signal; and (d) outputting the pulmonary pressure signal in a human perceivable format. - View Dependent Claims (26, 28, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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27. A pulmonary monitoring method comprising:
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detecting a physiological characteristic of a patient associated with pressure changes in such a patient'"'"'s extra-thoracic arterial circulation and for outputting a first signal indicative of such pressure changes, and wherein detecting a physiological characteristic of a patient includes providing an invasive blood pressure sensor within a patient'"'"'s extra-thoracic arterial circulation; and producing, using a controller, a pulmonary pressure signal as a measure of such a patient'"'"'s intra- thoracic pressure due to respiration by isolating breath related pressure variations in the first signal.
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29. A pulmonary monitoring method comprising:
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providing a pulmonary monitoring system including (a) a sensing system adapted to detect a physiological characteristic of a patient associated with pressure changes in such a patient'"'"'s extra-thoracic arterial circulation, and (b) a controller; detecting such a physiological characteristic using the sensing system and outputting a first signal indicative of such pressure changes to the controller; and using the controller to produce a pulmonary pressure signal as a measure of such a patient'"'"'s intra-thoracic pressure due to respiration by isolating breath related pressure variations in the first signal, and wherein producing the pulmonary pressure signal comprises; determining frequency components of the first signal; identifying a respiratory rate frequency component (fRR) from the frequency components of the first signal; and filtering the first signal based on the respiratory rate frequency component fRR so as to isolate the respiratory rate frequency component fRR from the first signal to produce the pulmonary pressure signal. - View Dependent Claims (30, 31, 32, 33)
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34. A pulmonary monitoring method comprising:
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providing a pulmonary monitoring system including (a) a sensing system adapted to detect a physiological characteristic of a patient associated with pressure changes in such a patient'"'"'s extra-thoracic arterial circulation, and (b) a controller; detecting such a physiological characteristic using the sensing system and outputting a first signal indicative of such pressure changes to the controller; and using the controller to produce a pulmonary pressure signal as a measure of such a patient'"'"'s intra-thoracic pressure due to respiration by isolating breath related pressure variations in the first signal, and wherein producing the pulmonary pressure signal comprises; determining frequency components of the first signal; identifying a heart rate frequency component fHR from the frequency components of the first signal; and filtering the physiologic signal based on the heart rate frequency component fHR so as to remove the heart rate frequency component fHR from the physiologic signal, thereby isolating a respiratory rate frequency component fRR of the first signal to produce the pulmonary pressure signal. - View Dependent Claims (35, 36)
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37. A pulmonary monitoring method comprising:
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providing a pulmonary monitoring system including (a) a sensing system adapted to detect a physiological characteristic of a patient associated with pressure chances in such a patient'"'"'s extra-thoracic arterial circulation, and (b) a controller; detecting such a physiological characteristic using the sensing system and outputting a first signal indicative of such pressure changes to the controller; and using the controller to produce a pulmonary pressure signal as a measure of such a patient'"'"'s intra-thoracic pressure due to respiration by isolating breath related pressure variations in the first signal, and wherein producing a pulmonary pressure signal comprises; determining frequency components of the first signal, including a respiratory rate frequency component fRR and a heart rate frequency component fHR; identifying a respiratory rate frequency component fRR from the frequency components of the first signal; identifying a heart rate frequency component fHR from the frequency components of the first signal; and filtering the first signal based on the respiratory rate frequency component fRR and the heart rate frequency component fHR so as to isolate the respiratory rate frequency component fRR from the first signal to produce the pulmonary pressure signal. - View Dependent Claims (38, 39)
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Specification