Method and apparatus for the measurement of cardiac output
AssigneeMonitoring Technology Corporation
InventorsDavid Marston Band, Nicholas William Fox Linton, Robert Anthony Fox Linton, Terence Kevin O'Brien
Life of this patent
Estimating the term…
Abstract
A method for the measurement of cardiac output in a patient in which the arterial blood pressure waveform of a patient from a blood pressure monitoring device over a period of time is subjected to various transformations and corrections, including a Fourier analysis in order to obtain the modulus of the first harmonic. The nominal stroke volume is then determined from the first harmonic and data relating to the arterial blood pressure and heart rate. The nominal cardiac output is then obtained from the nominal stroke volume.
Claims16
A method for the measurement of cardiac output in a patient, which method comprises the steps of:
- (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 data obtained in step (i) to Fourier analysis in order to obtain the modulus of the first harmonic;
- (iii) determining the nominal stroke volume from the modulus of the first harmonic obtained in step (ii) and data relating to the arterial blood pressure and the heart rate;
- and
- (iv) obtaining the nominal cardiac output and/or the systemic vascular resistance from data obtained in step (iii).
A method for the measurement of cardiac output in a patient, which method comprises the steps of:
- (a) recording and storing the arterial blood pressure waveform of a patient from a blood pressure monitoring device over a period of time;
- (b) subjecting the waveform obtained in step (a) to a non-linear transformation that corrects for the variation of the characteristics of the arterial system with pressure;
- (c) subjecting the data obtained in step (b) to Fourier analysis in order to obtain the modulus of the first harmonic;
- (d) determining the nominal stroke volume from the modulus of the first harmonic obtained in step (c) and data relating to the heart rate and optionally the arterial blood pressure;
- and
- (e) obtaining the nominal cardiac output and/or the systemic vascular resistance from data obtained in step (d).
An apparatus for the measurement of cardiac output in a patient, which comprises:
- (1) means for recording and storing the arterial blood pressure waveform of a patient from a blood pressure monitoring device over a period of time;
- (2) means for Fourier analysis of the arterial blood pressure waveform to obtain the modulus of the first harmonic;
- (3) means for deriving the nominal stroke volume from the modulus of the first harmonic and data relating to the arterial blood pressure and the heart rate;
- and
- (4) means for calculating the nominal cardiac output and/or the systemic vascular resistance.
An apparatus for the measurement of cardiac output in a patient, which method comprises the steps of:
- (A) means for recording and storing the arterial blood pressure waveform of a patient from a blood pressure monitoring device over a period of time;
- (B) means for transforming the arterial blood pressure waveform to correct for the variation of the characteristics of the arterial system with pressure;
- (C) means for the Fourier analysis of the transformed data to obtain the modulus of the first harmonic of the waveform;
- (D) means for determining the nominal stroke volume from the modulus of the first harmonic and data relating to the heart rate and optionally the arterial blood pressure;
- and
- (E) means for calculating the nominal cardiac output and/or the systemic vascular resistance.
Dependencies are inferred from the claim text.