Method of assessing blood volume using photoelectric plethysmography
First Claim
1. A method for assessing changes in blood volume within a subject, the method comprising:
- generating a cardiovascular waveform representing physiological characteristics of a subject;
detecting changes in blood volume of the subject by analyzing the cardiovascular waveform using a processor, wherein the analyzing of the cardiovascular waveform includes;
applying harmonic analysis to the cardiovascular waveform;
extracting a signal created by ventilation; and
analyzing changes in signal strength of the extracted signal to detect changes in blood volume of the subject.
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Abstract
A method and system for assessing blood volume within a subject includes generating a cardiovascular waveform representing physiological characteristics of a subject and determining blood volume of the subject by analyzing the cardiovascular waveform. The step of analyzing includes generating a first trace of the per heart-beat maximums of the cardiovascular waveform, which is representative of the systolic pressure upon the cardiovascular signal, generating a second trace of the per heart-beat minimums of the cardiovascular waveform, which is representative of the diastolic pressure upon the cardiovascular signal, and comparing the respective first trace and the second trace to generate an estimate of relative blood volume within the subject. In accordance with an alternate method of analyzing harmonic analysis is applied to the cardiovascular waveform, extracting a frequency signal created by ventilation and applying the extracted frequency signal in determining blood volume of the subject.
71 Citations
62 Claims
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1. A method for assessing changes in blood volume within a subject, the method comprising:
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generating a cardiovascular waveform representing physiological characteristics of a subject; detecting changes in blood volume of the subject by analyzing the cardiovascular waveform using a processor, wherein the analyzing of the cardiovascular waveform includes; applying harmonic analysis to the cardiovascular waveform; extracting a signal created by ventilation; and analyzing changes in signal strength of the extracted signal to detect changes in blood volume of the subject. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for facilitating detection of physiological changes of a subject, the method comprising:
analyzing a cardiovascular waveform representing physiological characteristics of a subject using a processor, wherein the analyzing of the cardiovascular waveform includes; identifying a first component of the cardiovascular waveform reflective of a cardiovascular impact of respiration; and analyzing a characteristic of the first component reflective of amplitude variations of the first component, wherein the amplitude variations are indicative of changes in blood volume of the subject. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A system for assessing changes in blood volume within a subject, the system comprising:
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a probe adapted for generating a cardiovascular waveform of a subject; and a processor configured for analyzing the cardiovascular waveform to determine changes in blood volume of the subject, wherein the analyzing of the cardiovascular waveform includes; applying harmonic analysis to the cardiovascular waveform; extracting a signal created by ventilation; and applying the extracted signal in determining the changes in blood volume of the subject, wherein the applying the extracted signal includes monitoring changes in a signal strength of the extracted signal in the frequency domain. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42)
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43. A system for facilitating detection of physiological changes of a subject, the system comprising:
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a probe adapted for generating a cardiovascular waveform representing physiological characteristics of a subject; and a processor configured for analyzing the cardiovascular waveform, wherein the analyzing the cardiovascular waveform includes identifying a first component of the cardiovascular waveform reflective of a cardiovascular impact of respiration, and analyzing a characteristic of the first component reflective of amplitude variations of the first component, wherein the amplitude variations are indicative of changes in blood volume of the subject. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
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Specification