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WO1992006633A1 - Procede et appareil de mesure du debit cardiaque - Google Patents

Procede et appareil de mesure du debit cardiaque Download PDF

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Publication number
WO1992006633A1
WO1992006633A1 PCT/US1991/007523 US9107523W WO9206633A1 WO 1992006633 A1 WO1992006633 A1 WO 1992006633A1 US 9107523 W US9107523 W US 9107523W WO 9206633 A1 WO9206633 A1 WO 9206633A1
Authority
WO
WIPO (PCT)
Prior art keywords
cardiac output
determining
heart rate
ejection time
surface area
Prior art date
Application number
PCT/US1991/007523
Other languages
English (en)
Inventor
Stanley M. Finkelstein
Jay N. Cohn
Original Assignee
Hypertension Diagnostics, Inc.
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.)
Filing date
Publication date
Application filed by Hypertension Diagnostics, Inc. filed Critical Hypertension Diagnostics, Inc.
Publication of WO1992006633A1 publication Critical patent/WO1992006633A1/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
    • A61B5/02—Detecting, measuring or recording for evaluating the cardiovascular system, e.g. pulse, heart rate, blood pressure or blood flow
    • A61B5/026—Measuring blood flow
    • A61B5/029—Measuring blood output from the heart, e.g. minute volume
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording for evaluating the cardiovascular system, e.g. pulse, heart rate, blood pressure or blood flow
    • A61B5/024—Measuring pulse rate or heart rate

Definitions

  • the present invention pertains generally to the field of medicine, and more particularly to cardiology and biomedical engineering.
  • Cardiac output is an important hemodynamic variable widely used in the field of cardiology for diagnosis and other characterizations of the cardiovascular system. It is routinely used as a diagnostic measure of cardiac function, particularly in the diagnosis of congestive heart failure and related cardiac disease. Characterizations of the cardiovasculature using the Windkessel model, employed to obtain measures of vascular compliance, also require a measure of cardiac output. Thermodilution and dye dilution procedures are considered two of the most accurate measures of cardiac output. They are, however, surgically invasive procedures which require catheterization of the subject. As such, these procedures are inconvenient, time consuming and expensive, as well as undesirable from the patient's perspective.
  • a cardiac output meter having transducer means for measuring the blood pressure waveform of the patient and generating a corresponding analog signal, means for digitizing the analog signal generated by the transducer means, means for determining, by digital signal processing of the digitized blood pressure waveform, the ejection time and heart rate, and means for calculating and displaying a measure of cardiac output based on the heart rate, ejection time, and the patient's body surface area and age.
  • means for automatically determining the body surface area by standard formula or nomogra based on input variables including the subject's height and weight.
  • an arterial blood pressure waveform there is measured, either noninvasively or invasively, an arterial blood pressure waveform.
  • the waveform data are processed to determine the ejection time of the heart.
  • the heart rate is measured, and body surface area is determined by standard formula or by nomogram, using the subject's height and weight. Stroke volume is then determined in accordance with the following formula:
  • SVA -6.6 + 0.25 x ET + 40.4 x BSA - 0.51 x Age - 0.62 x HR, where SVA equals stroke volume in ml/beat, ET is ejection time in msec, BSA is body surface area in square meters, Age is the age of the subject, and HR is heart rate (beats per minute) . Cardiac output is determined by multiplying SVA times the heart rate HR.
  • the present invention thus provides method and apparatus for determining cardiac output without special instrumentation beyond that normally required for nemo- dynamic monitoring or vascular compliance determination.
  • the invention requires no calibration, is easily applied, can be done noninvasively, and, even if done invasively, is much simpler than the standard dilution technique.
  • the invention thus has considerable potential for use in screening subjects based on stroke volume/cardiac output determinations.
  • Figure 1 is a schematic block diagram of the cardiac output meter according to the present invention
  • Figure 2A and 2B comprise a schematic flow chart of the software of the present invention
  • Figure 3 is illustrative example of typical arterial pulse contours in healthy patients
  • Figure 4 is illustrative example of typical arterial pulse contours in diseased patients
  • Figure 5 is a scatterplot of invasively measured stroke volume using thermal dilution vs. stroke volume obtained from the present invention for 71 cases which formed the basis for the development of the present invention
  • Figure 6 is a scatterplot of invasively measured stroke volume using thermodilution vs. stroke volume measured using the present invention for 39 separate, independent cases used to test the accuracy of the meter of the present invention.
  • the cardiac output meter 10 includes an analog to digital convertor (A/D) 12, preferably 12-bit, a microprocessor unit 14, for instance a 30386 model by Intel, a keyboard input 16, display 18, ROM 20, RAM 22 and modem 24.
  • A/D analog to digital convertor
  • microprocessor unit 14 for instance a 30386 model by Intel
  • keyboard input 16 display 18, ROM 20, RAM 22 and modem 24.
  • An input port 30 is provided to receive analog signal input from an arterial pressure transducer 34.
  • a printer output port 38 and a telephone port 40 are provided from microprocessor 14 and modem 24, respectively.
  • transducer 34 is preferably a Statham P23Db pressure transducer, connected to a brachial artery by an 18-gauge, 2-inch Teflon catheter.
  • This catheter- transducer system has an undamped natural frequency higher than 25 HZ and a damping coefficient less than 0.5, providing an acceptable frequency response. It shall be understood, however, that while the brachial artery is preferred, other arterial peripheral locations for obtaining the pulse pressure contour can be substituted.
  • a non-invasive transducer 34 unit can also be used, for example, a finger-cuff transducer unit using a counter pulsation technique wherein the waveform is detected by balancing the pressure in the finger cuff with that in the finger.
  • a commercially available finger-cuff transducer unit is the Finapres® Continuous NIBP Monitor Model 2300, from Ohmeda Monitoring Systems division of the BOC Group, Inc., 355 Inverness Drive South, Engelwood, Colorado 80112-5810. The Finapres® device produces an analog output signal which is equivalent to the output signal of the P23Db pressure transducer, and can be fed through port 30 to A/D converter 12.
  • Another non-invasive transducer unit acceptable for use with the present invention is the Model 506 Non-invasive Patient Monitor from Criticare Systems, Inc., 20900 Swenson Drive, Suite 398, Waukesha, Wisconsin 53186.
  • the software component 50 of the meter 10 is illustrated in block diagram flow-chart form in Figs. 2A and B.
  • Software within meter 10 is preferably maintained in ROM 20 and is referenced by microprocessor 14.
  • software 50 can be stored in magnetic or other digital form on a floppy computer disk or equivalent connected so as to be accessed by the microprocessor.
  • Software 50 runs on microprocessor 14 to control the acquisition of arterial pressure pulse data, and to perform other meter functions, as described below.
  • An initialization and mode select routine 52 is provided for initializing microprocessor 14, including prompting the user to enter patient information. including the patient's age, height (in centimeters) and weight (in kilograms) , and/or body surface area (in square meters). Routine 52 further allows either the meter mode or communication mode to be selected. If the meter mode is selected, A/D convertor 12 is activated (54) to digitize an analog pressure pulse signal generated by transducer 34.
  • Figs. 3 and 4 illustrate typical brachial artery pulse pressure contours for nor otensive and hypertensive patients, respectively.
  • Routine 56 provides that the artery is metered for approximately 30 seconds, producing in the range of 25 to 60 digitized pulses, depending on the heart rate.
  • the stream of digitized pulses are stored in RAM 22 in the form of a continuous series of periodic time dependent data byte samples, with each data byte corresponding to the instantaneous pressure of the artery.
  • Routine 60 determines body surface area by standard formula, or alternatively looks it up in a nomogram table stored in memory, using the patient's height and weight data. Alternatively, body surface area can be determined by the physician or other care giver and entered into the meter at routine 52, as noted above.
  • a formula for determining BSA known to work in connection with the present invention is:
  • BSA (m -2 ) 0.0072 X weight 0.425 0 ' 425 X height °' 725 where weight is in kilograms and height is in centimeters.
  • Selection routine 70 analyzes the recorded wave data to determine ejection time. First, routine 70 selects a group of consecutive representative beats (it has been found that six to ten beats are preferred but the number used is in no way critical to the invention) preferably of comparatively low noise content. Representative beats are identified by establishing windows of permissible heart rate and mean arterial pressure values whereby abnormally fast or slow heartbeats, or high or low pressures can be rejected. The routine can thus pick the series of beats which is most representative. The heart rate (HR) is also determined by this routine, by counting the number of beats per unit time. Where possible it is preferable that the windows be tailored to the patient, thus allowing more precise selection of representative beats. Routine 70 determines ejection time as follows.
  • the heart waveforms are marked for analysis.
  • a clinician can identify the onset of systole and the upstroke, by correlating to the first heart sound Sj.
  • the end of systole, signalled by diastole, can be found manually by correlating to the second heart sound S 2 .
  • Ejection time is then determined by the time between the occurrence of systole to diastole. For example, in Figs. 3 and 4 ejection time is marked by the respective segments A and B, assuming a waveform obtained proximate the heart.
  • Routine 70 uses a software analysis algorithm at routine 70 to predict and select the segment in each wave most probably corresponding to ejection time.
  • Routine 70 searches the waveform data for the waveform upstroke marking systole, and then for the dicrotic notch (D), looked for after the peak of the systolic upstroke, and marks the onset of diastole just before the location of the dicrotic notch on the wave.
  • the ejection time (ET) is then determined from the location of the onset of systole and diastole.
  • Transit time effects due to the distance between the aorta and the measurement site are taken into account in the ejection time measurement by moving back a predetermined interval (depending on where with arterial waveform is measured in the arterial system) from the trough of the dicrotic notch to determine end of systole for the purposes of this ejection time determination.
  • the ejection time is thus the time between the upstroke (beginning of systole) and this point marking the end of systole.
  • an interval of 25 milliseconds has been found satisfactory to compensate for transit time effects. Shorter or longer intervals would be appropriate for waveforms obtained closer to or further from the heart, respectively.
  • device 10 can include means for digitizing an analog signal representing the heart sounds, software for identifying the first and second heart sounds S_ and S 2 , and for correlating them to the digitized arterial waveform to identify the onset of systole and diastole.
  • Routine 71 calculates stroke volume using the following formula:
  • Routine 72 is provided to indicate via display 18 the calculated value, either graphically, for instance a bar graph showing the magnitude of cardiac output or stroke volume on a scale, or by displaying a corresponding numerical value, on the LCD display.
  • Routine 80 is provided to report the analysis results on an optional printer 42.
  • Meter 10 also includes communications capability, whereby the measured cardiac output data (or, if desired other stored vascular parameters) may be communicated to further computer equipment 44 in a clinic or hospital, such as a personal computer or minicomputer. Accordingly, meter 10 may be used by a patient at home with measured cardiac output being transmitted back to a treating hospital or clinic for review or for further analysis.
  • software 50 provides a communications mode including routines 145 and 146, which provide for establishing a communication link with remote system and for downloading the cardiac output measurement.
  • a clinic or hospital computer 44 is provided to communicate with meter 10 using a standard modem-telephone link.
  • Figure 2B illustrates in diagrammatic form the software 150 provided for clinic computer 44.
  • a routine 152 is provided for establishing the communication link with meter 10.
  • Computer 44 preferably includes an auto ⁇ answer modem so that meter 10 may establish communication therewith with a minimum of effort.
  • Data acquisition routine 154 is provided to receive one or more cardiac output values, which may be stored in RAM 22.
  • Report/display routine 156 provides reporting or display of downloaded cardiac output values for use by the hospital or clinic staff.
  • Figure 5 is a scatterplot of invasively measured stroke volume (in ml/heart beat) using thermodilution (the "Gold Standard”) vs.
  • Figure 6 is a scatterplot of invasively measured stroke volume (in ml/heart beat) using thermodilution (the "Gold Standard”) vs. stroke volume (in ml/heart beat) measured using the meter of the present invention, for 39 separate, independent cases.
  • the subjects of this study ranged from 19-75 in age.
  • Figure 6 shows that in 88% of the cases, there was less than a (+-)25% difference between the cardiac output measurement obtained by thermodilution and that obtained using the present invention.
  • the accuracy of the meter as currently understood from the cases against which it has been tested, is thus adequate to provide a cardiac output measure adequate for many applications wherein an approximate measure is acceptable. This accuracy compares favorably against the 10-20% reproducibility of the most accurate dilution techniques.
  • the present invention also includes a method for measuring stroke volume/cardiac output. The method includes the following steps:
  • ET ejection time in msec
  • BSA body surface area in square meters
  • HR heart rate (bpm) ;
  • the formula for determining cardiac output set forth herein will be further refined and adjusted as further data is collected and/or as adjustments to constants and factors are determined to produce more accurate determinations of cardiac output.
  • the formula may be adjusted by performing a multiple linear regression to fit a new formula on "Gold Standard" data. Accordingly, it shall be understood that the basic structure of the formula is to be emphasized. Also, it shall be understood that both cardiac output per se (SVA X heart rate) and SVA are considered measures of cardiac output for the purpose of the claims appended hereto. Moreover, it is contemplated that many changes and modifications may be made to the method and apparatus of the invention without departing from the spirit and scope of the claims appended hereto.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Cardiology (AREA)
  • Engineering & Computer Science (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Physiology (AREA)
  • Biophysics (AREA)
  • Pathology (AREA)
  • Hematology (AREA)
  • Biomedical Technology (AREA)
  • Physics & Mathematics (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)

Abstract

L'appareil décrit qui sert à mesurer le volume systolique/le débit cardiaque, comprend un transducteur (34) qui mesure la forme d'onde de la tension artérielle, un numériseur (12) qui numérise le signal analogique produit par le transducteur (34), et un processeur de signaux numériques (14, 20, 22) qui détermine le temps d'éjection et la fréquence cardiaque. Le circuit processeur (14) détermine le débit cardiaque en utilisant le temps d'éjection, la fréquence cardiaque, la superficie corporelle et l'âge du patient, le débit cardiaque ainsi mesuré étant affiché par l'appareil de mesure (18).
PCT/US1991/007523 1990-10-23 1991-10-11 Procede et appareil de mesure du debit cardiaque WO1992006633A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US60146090A 1990-10-23 1990-10-23
US601,460 1990-10-23

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Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0564492A1 (fr) * 1990-12-28 1993-10-13 Regents Of The University Of Minnesota Instrument de mesure d'impedance vasculaire
WO1994014372A1 (fr) * 1992-12-18 1994-07-07 Cohen, Avi Mesure en continu de la sortie cardiaque et de la resistance du systeme vasculaire (svr)
US5406952A (en) * 1993-02-11 1995-04-18 Biosyss Corporation Blood pressure monitoring system
WO1997024982A1 (fr) * 1996-01-05 1997-07-17 Monitoring Technology Limited Procede et appareils permettant de mieux mesurer le debit cardiaque
WO1999002086A1 (fr) * 1997-07-10 1999-01-21 Monitoring Technology Limited Procede et systeme ameliores de mesure du debit cardiaque
WO2003037181A3 (fr) * 2001-10-31 2004-02-26 Robert Alan Hirsh Procede non invasif et dispositif de surveillance de parametres cardiaques
US6758822B2 (en) 1999-04-27 2004-07-06 Salvatore Romano Method and apparatus for measuring cardiac output
WO2004064631A1 (fr) * 2003-01-22 2004-08-05 Uscom Limited Procede et systeme pour determiner des caracteristiques sanguines
WO2005084536A1 (fr) * 2004-03-05 2005-09-15 Atcor Medical Pty Limited Procede et appareil permettant de determiner le debit cardiaque a partir de la forme d'impulsion de la pression arterielle
WO2006050725A1 (fr) * 2004-11-10 2006-05-18 Medicus Engineering Aps Procede et appareil permettant d'enregistrer et de presenter des donnees physiologiques
US7220230B2 (en) 2003-12-05 2007-05-22 Edwards Lifesciences Corporation Pressure-based system and method for determining cardiac stroke volume
WO2007134394A1 (fr) * 2006-05-22 2007-11-29 Uscom Limited Système et méthode de mesure cardiaque
US7422562B2 (en) 2003-12-05 2008-09-09 Edwards Lifesciences Real-time measurement of ventricular stroke volume variations by continuous arterial pulse contour analysis
US7452333B2 (en) 2003-12-05 2008-11-18 Edwards Lifesciences Corporation Arterial pressure-based, automatic determination of a cardiovascular parameter
US7630766B2 (en) 2002-07-03 2009-12-08 Uscom Limited Exercise responsive pacemaker tuning method using Doppler blood flow measurements to adjust pacing for optimized flow
US7651466B2 (en) 2005-04-13 2010-01-26 Edwards Lifesciences Corporation Pulse contour method and apparatus for continuous assessment of a cardiovascular parameter
US7761141B2 (en) 2001-10-31 2010-07-20 Robert Hirsh Non-invasive method and device to monitor cardiac parameters without use of electrical-mechanical interval
US20210228095A1 (en) * 2018-04-30 2021-07-29 Philips Medizin Systeme Böblingen Gmbh Method for determining a cardiac stroke volume

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4137910A (en) * 1976-09-30 1979-02-06 Murphy Donald H Method and means for measuring cardiac pumping performance of left ventricle
US4562843A (en) * 1980-09-29 1986-01-07 Ljubomir Djordjevich System for determining characteristics of blood flow
US4807638A (en) * 1987-10-21 1989-02-28 Bomed Medical Manufacturing, Ltd. Noninvasive continuous mean arterial blood prssure monitor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4137910A (en) * 1976-09-30 1979-02-06 Murphy Donald H Method and means for measuring cardiac pumping performance of left ventricle
US4562843A (en) * 1980-09-29 1986-01-07 Ljubomir Djordjevich System for determining characteristics of blood flow
US4807638A (en) * 1987-10-21 1989-02-28 Bomed Medical Manufacturing, Ltd. Noninvasive continuous mean arterial blood prssure monitor

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CIRCULATION, Volume 46, issued September 1972, EDWIN L. ALDERMAN et al., "Evaluation of the Pulse-Contour Method of Determining Stroke Volume in Man", See pages 546-558. *
EUROPEAN HEART JOURNAL, 4, issued 1983, T. TAJIMI et al., "Evaluation of pulse Contour Methods in Calculating Stroke Volume from Pulmonary Artery Pressure Curve (Comparison with Aortic Pressure Curve)", See pages 502-511. *

Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0564492A4 (fr) * 1990-12-28 1994-10-12 Univ Minnesota Instrument de mesure d'impedance vasculaire.
EP0564492A1 (fr) * 1990-12-28 1993-10-13 Regents Of The University Of Minnesota Instrument de mesure d'impedance vasculaire
WO1994014372A1 (fr) * 1992-12-18 1994-07-07 Cohen, Avi Mesure en continu de la sortie cardiaque et de la resistance du systeme vasculaire (svr)
US5406952A (en) * 1993-02-11 1995-04-18 Biosyss Corporation Blood pressure monitoring system
WO1997024982A1 (fr) * 1996-01-05 1997-07-17 Monitoring Technology Limited Procede et appareils permettant de mieux mesurer le debit cardiaque
WO1999002086A1 (fr) * 1997-07-10 1999-01-21 Monitoring Technology Limited Procede et systeme ameliores de mesure du debit cardiaque
AU729956B2 (en) * 1997-07-10 2001-02-15 Lidco Group Plc Improved method and apparatus for the measurement of cardiac output
US6348038B1 (en) 1997-07-10 2002-02-19 Monitoring Technology Limited Method and apparatus for the measurement of cardiac output
US6758822B2 (en) 1999-04-27 2004-07-06 Salvatore Romano Method and apparatus for measuring cardiac output
US7761141B2 (en) 2001-10-31 2010-07-20 Robert Hirsh Non-invasive method and device to monitor cardiac parameters without use of electrical-mechanical interval
US8843194B2 (en) 2001-10-31 2014-09-23 Robert Hirsh Non-invasive method and device to monitor cardiac parameters
US8808191B2 (en) 2001-10-31 2014-08-19 Robert Hirsh Non-invasive method and device to monitor cardiac parameters
US7054679B2 (en) 2001-10-31 2006-05-30 Robert Hirsh Non-invasive method and device to monitor cardiac parameters
WO2003037181A3 (fr) * 2001-10-31 2004-02-26 Robert Alan Hirsh Procede non invasif et dispositif de surveillance de parametres cardiaques
US7657306B2 (en) 2001-10-31 2010-02-02 Robert Hirsh Non-invasive method and device to monitor cardiac parameters
US7630766B2 (en) 2002-07-03 2009-12-08 Uscom Limited Exercise responsive pacemaker tuning method using Doppler blood flow measurements to adjust pacing for optimized flow
WO2004064631A1 (fr) * 2003-01-22 2004-08-05 Uscom Limited Procede et systeme pour determiner des caracteristiques sanguines
US7789835B2 (en) 2003-01-22 2010-09-07 Uscom Limited Methods and systems for determining cardiac output based on a valve cross sectional area estimate
US8721556B2 (en) 2003-12-05 2014-05-13 Edwards Lifesciences Corporation Arterial pressure-based, automatic determination of a cardiovascular parameter
US7452333B2 (en) 2003-12-05 2008-11-18 Edwards Lifesciences Corporation Arterial pressure-based, automatic determination of a cardiovascular parameter
US7422562B2 (en) 2003-12-05 2008-09-09 Edwards Lifesciences Real-time measurement of ventricular stroke volume variations by continuous arterial pulse contour analysis
US7785263B2 (en) 2003-12-05 2010-08-31 Edwards Lifesciences Corporation Pressure-based system and method for determining cardiac stroke volume
US7967757B2 (en) 2003-12-05 2011-06-28 Edwards Lifesciences Corporation Arterial pressure-based, automatic determination of a cardiovascular parameter
US7220230B2 (en) 2003-12-05 2007-05-22 Edwards Lifesciences Corporation Pressure-based system and method for determining cardiac stroke volume
WO2005084536A1 (fr) * 2004-03-05 2005-09-15 Atcor Medical Pty Limited Procede et appareil permettant de determiner le debit cardiaque a partir de la forme d'impulsion de la pression arterielle
WO2006050725A1 (fr) * 2004-11-10 2006-05-18 Medicus Engineering Aps Procede et appareil permettant d'enregistrer et de presenter des donnees physiologiques
US9521957B2 (en) 2004-11-10 2016-12-20 Medicus Engineering Aps Hand-held device for self-measurement and recording of a heart rate variability examination
US7651466B2 (en) 2005-04-13 2010-01-26 Edwards Lifesciences Corporation Pulse contour method and apparatus for continuous assessment of a cardiovascular parameter
US8801618B2 (en) 2005-04-13 2014-08-12 Feras Hatib Pulse contour method and apparatus for continuous assessment of a cardiovascular parameter
WO2007134394A1 (fr) * 2006-05-22 2007-11-29 Uscom Limited Système et méthode de mesure cardiaque
US20210228095A1 (en) * 2018-04-30 2021-07-29 Philips Medizin Systeme Böblingen Gmbh Method for determining a cardiac stroke volume

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