US4676253A
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Method and apparatus for noninvasive determination of cardiac output
Assignee: Doll Medical Research Inc
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Filing: 1985-07-18
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Granted: 1987-06-30
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Expires: 2005-07-18
Abstract
Abstract A determination of cardiac output of a living being is obtained noninvasively from measurements of heart rate and pulse timing points from a blood flow waveform in relation to the "R" line from a corresponding ECG signal. The blood flow waveform may be obtained indirectly, by differentiating the output of a plethysmograph or an instantaneous blood pressure sensor or by integrating the output of a doppler sensor, or indirectly from a magnetic flowmeter, for example. Heart rate and an "R" line trigger signal may be obtained from an electrocardiogram signal. Experimentally obtained heart rate and pulse timing data were compared with invasively measured cardiac output and were processed by regression analysis to yield an equation correlation of 0.73.
Inventors
- 👤 Warren Newman
- 👤 Alfred V. Persson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:28
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/02; A61B5/026; A61B5/0295; A61B5/029; A61B5/72; A61B5/7235; A61B5/7239
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
169 words
A method for determining the cardiac index of a living being, the method comprising: sensing a series of electrocardiac first signals sensed at a first location on the skin surface of the living being adjacent to the heart for use as synchronizing and timing signals; sensing a series of second signals sensed at a second location on the skin surface of the living being that are related to instantaneous blood flow; processing the first signals to obtain an average heart rate value by averaging the durations between successive "R" lines of each electrocardiac wave; processing the second signals to obtain a blood flow waveform signal corresponding to instantaneous blood flow at the second location; measuring the time from each "R" line signal to a predetermined point on the corresponding blood flow waveform signal to determine at least one corresponding pulse delay timing value; and processing the average heart rate value and the pulse delay timing value to obtain a final value representing the cardiac index of the living being.
Claim 2
Independent Claim
169 words
A method for determining the cardiac index of a living being, the method comprising: sensing a series of electrocardiac first signals sensed at a first location on the skin surface of the living being adjacent to the heart for use as synchronizing and timing signals; sensing a series of second signals sensed at a second location on the skin surface of the living being that are related to instantaneous blood flow; processing the first signals to obtain an average heart rate value by averaging the durations between successive "R" lines of each electrocardiac wave; processing the second signals to obtain a blood flow waveform signal corresponding to instantaneous blood flow at the second location; measuring the time from each "R" line signal to a predetermined point on the corresponding blood flow waveform signal to determine at least one corresponding pulse delay timing value; and processing the average heart rate value and the pulse delay timing value to obtain a final value representing the cardiac index of the living being.
Claim 3
Dependent Claim
54 words
The method according to claim 1 wherein the step of measuring the time from each "R" line signal to at least one predetermined point on the corresponding blood flow waveform signal comprises measuring the time from each "R" line signal to the peak of the systolic pulse of the corresponding blood flow waveform signal.
Claim 4
Dependent Claim
54 words
The method according to claim 1 wherein the step of measuring the time from each "R" line signal to at least one predetermined point on the corresponding blood flow waveform signal comprises measuring the time from each "R" line signal to the onset of the systolic pulse of the corresponding blood flow waveform signal.
Claim 5
Dependent Claim
51 words
The method according to claim 1 wherein the step of sensing a second signal at a second location on the skin surface of the living being comprises sensing the instantaneous impedance changes between two sites spaced apart along the length dimension of the limb to obtain an instantaneous blood volume signal.
Claim 6
Dependent Claim
28 words
The method according to claim 4 wherein the step of processing the second signal to obtain a blood flow waveform signal comprises differentiating the instantaneous blood volume signal.
Claim 7
Dependent Claim
86 words
The method according to claim 1 wherein the step of processing the average heart rate value and the pulse delay timing value to obtain a final value representing the cardiac index comprises multiplying the average heart rate value by a first predetermined constant value to obtain a modified average heart rate value; multiplying the pulse delay timing value by a predetermined constant value to obtain a modified pulse delay timing value; and adding the modified average heart rate value to the modified pulse delay timing value.
Claim 8
Dependent Claim
16 words
The method according to claim 6 wherein the second predetermined constant value is a negative number.
Claim 9
Dependent Claim
45 words
The method according to claim 7 wherein the step of processing the average heart rate value and the pulse delay timing value further comprises adding a third predetermined constant value signal to the sum of the modified average heart rate and pulse delay timing values.
Claim 10
Dependent Claim
76 words
The method according to claim 1 further comprising the step of: measuring the time from the onset to the peak of the systolic pulse portion of each blood flow waveform signal to obtain a systolic rise time value, modifying the final value processing step as follows: processing the systolic rise time value, the average heart rate value and the pulse delay timing value to obtain said final value representing the cardiac index of the living being.
Claim 11
Dependent Claim
151 words
Apparatus for determining the cardiac index of a living being, the apparatus comprising: means for sensing a series of electrocardiac first signals sensed on the skin surface of the living being; means for sensing a series of second signals on the skin surface of the living being related to instantaneous blood flow; means for processing the first signal to obtain an average heart rate value by averaging the times between successive "R" lines of each electrocardiac wave; means for processing the second signals to obtain a blood flow waveform signal; means for measuring the time from each "R" line signal to at least one predetermined point on the corresponding blood flow waveform signal to obtain at least one corresponding pulse delay timing value; and means for processing the average heart rate value and the pulse delay timing value to obtain a final value representing the cardiac index of the living being.
Claim 12
Dependent Claim
151 words
Apparatus for determining the cardiac index of a living being, the apparatus comprising: means for sensing a series of electrocardiac first signals sensed on the skin surface of the living being; means for sensing a series of second signals on the skin surface of the living being related to instantaneous blood flow; means for processing the first signal to obtain an average heart rate value by averaging the times between successive "R" lines of each electrocardiac wave; means for processing the second signals to obtain a blood flow waveform signal; means for measuring the time from each "R" line signal to at least one predetermined point on the corresponding blood flow waveform signal to obtain at least one corresponding pulse delay timing value; and means for processing the average heart rate value and the pulse delay timing value to obtain a final value representing the cardiac index of the living being.
Claim 13
Dependent Claim
16 words
The apparatus of claim 10 wherein the means for sensing said second signal comprises a plethysmograph.
Claim 14
Dependent Claim
17 words
The apparatus of claim 10 wherein the means for sensing said second signal comprises a doppler device.
Claim 15
Dependent Claim
17 words
The apparatus of claim 10 wherein the means for sensing said second signal comprises an electromagnetic flowmeter.
Claim 16
Dependent Claim
17 words
The apparatus of claim 10 wherein the means for sensing said second signal comprises a strain gage.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-06-29 | 1990-12-29 | 1991-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-29 | 1994-12-29 | 1995-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-29 | 1998-12-29 | 1999-06-30 | $7700.00 | Window Closed / Lapsed |