Non-invasive assessment of cardiac output during exercise in healthy young humans: comparison between Modelflow method and Doppler echocardiography method.

AIMS The Modelflow method can estimate cardiac output from arterial blood pressure waveforms using a three-element model of aortic input impedance (aortic characteristic impedance, arterial compliance, and systemic vascular resistance). We tested the reliability of a non-invasive cardiac output estimation during submaximal exercise using the Modelflow method from finger arterial pressure waveforms collected by Portapres in healthy young humans. METHODS The Doppler echocardiography method was used as a reference method. Sixteen healthy young subjects (nine males and seven females) performed a multi-stage cycle ergometer exercise at an intensity corresponding to 70, 90, 110 and 130% of their individual ventilatory threshold for 2 min each. The simultaneous estimation of cardiac output (15 s averaged data) using the Modelflow and Doppler echocardiography methods was performed at rest and during exercise. RESULTS AND CONCLUSION The Modelflow-estimated cardiac output correlated significantly with the simultaneous estimates by the Doppler method in all subjects (r = 0.87, P < 0.0001) and the SE of estimation was 1.93 L min-1. Correlation coefficients in each subject ranged from 0.91 to 0.98. Although the Modelflow method overestimated cardiac output, the errors between two estimates were not significantly different among the exercise levels. These results suggest that the Modelflow method using Portapres could provide a reliable estimation of the relative change in cardiac output non-invasively and continuously during submaximal exercise in healthy young humans, at least in terms of the relative changes in cardiac output.

[1]  L. M. Sheldahl,et al.  Determination of Stroke Volume and Cardiac Output During Exercise: Comparison of Two-Dimensional and Doppler Echocardiography, Fick Oximetry, and Thermodilution , 1987, Circulation.

[2]  S. Onodera,et al.  Effects of endurance training on the size and blood flow of the arterial conductance vessels in humans. , 1998, Acta physiologica Scandinavica.

[3]  G. Langewouters,et al.  The static elastic properties of 45 human thoracic and 20 abdominal aortas in vitro and the parameters of a new model. , 1984, Journal of biomechanics.

[4]  S. Eckert,et al.  Comparison of Portapres non-invasive blood pressure measurement in the finger with intra-aortic pressure measurement during incremental bicycle exercise , 2002, Blood pressure monitoring.

[5]  Jonathan Kraidin,et al.  Continuous noninvasive cardiac output as estimated from the pulse contour curve , 1992, Journal of Clinical Monitoring.

[6]  L. Ferrone,et al.  Test-retest reproducibility of maximum cardiac output by Doppler echocardiography. , 1998, The American journal of cardiology.

[7]  B Oeseburg,et al.  Non-invasive cardiac output assessment during moderate exercise: pulse contour compared with CO2 rebreathing. , 1999, Clinical physiology.

[8]  A. Vinet,et al.  Central and peripheral cardiovascular adaptations to exercise in endurance-trained children. , 2002, Acta physiologica Scandinavica.

[9]  J R Jansen,et al.  Computation of aortic flow from pressure in humans using a nonlinear, three-element model. , 1993, Journal of applied physiology.

[10]  F Baisch,et al.  Noninvasive cardiac output measurement by arterial pulse analysis compared with inert gas rebreathing. , 1993, Journal of applied physiology.