Patent ID: 6071244
Filing Date: 2000-06-06
Classification: A61B

Abstract:
A method for the measurement of cardiac output in a patient, which method comprises:(i) recording and storing the arterial blood pressure waveform of a patient from a blood pressure monitoring device over a period of time;(ii) subjecting the waveform obtained in (i) to a non-linear transformation that corrects for the variation of the characteristics of the arterial system with pressure and thereby obtaining a corrected waveform;(iii) subjecting the corrected waveform from (ii) to autocorrelation in order to derive the pulsatility which is equal to ##EQU2## where R(.tau.) is the autocorrelation function and .tau..sub.min is the value of .tau. at which the autocorrelation is at a minimum and heart rate of the corrected waveform;(iv) calculating the nominal stroke volume from the pulsatility;(v) obtaining the nominal cardiac output by multiplying the nominal stroke volume by the heart rate; and(vi) obtaining the cardiac output from the nominal cardiac output by means of a calibration factor.