Non-invasive cardiac output evaluation during a maximal progressive exercise test, using a new impedance cardiograph device.
One of the greatest challenges in exercise physiology is to develop a valid, reliable, non-invasive and affordable measurement of cardiac output (CO). The purpose of this study was to evaluate the reproducibility and accuracy of a new impedance cardiograph device, the Physio Flow, during a 1-min step incremental exercise test from rest to maximal peak effort. A group of 12 subjects was evaluated to determine the reproducibility of the method as follows: (1) each subject performed two comparable tests while their CO was measured by impedance cardiography using the new device (COImp1, COImp2), and (2) in a subgroup of 7 subjects CO was also determined by the direct Fick method (COFick) during the second test. The mean difference between the values obtained by impedance (i.e. COImp1-COImp2) was -0.009 l.min-1 (95% confidence interval: -4.2 l.min-1, 4.2 l.min-1), and CO ranged from 3.55 l.min-1 to 26.75 l.min-1 (n = 146). When expressed as a percentage, the difference (COImp1-COImp2) did not vary with increasing CO. The correlation coefficient between the values of COImp and COFick obtained during the second exercise test was r = 0.94 (P < 0.01, n = 50). The mean difference expressed as percentage was -2.78% (95% confidence interval: -27.44%, 21.78%). We conclude that COImp provides a clinically acceptable evaluation of CO in healthy subjects during an incremental exercise.
Richard
R
R
Service des Explorations Fonctionnelles Respiratoires, Cardio-Circulatories et de l'Exercice, Hôpitaux Universitaires de Strasbourg, Hôpital Civil, BP 426, 67091 Strasbourg, France. ruddy.richard@physio-ulp.u-strasbg.fr
Lonsdorfer-Wolf
E
E
Charloux
A
A
Doutreleau
S
S
Buchheit
M
M
Oswald-Mammosser
M
M
Lampert
E
E
Mettauer
B
B
Geny
B
B
Lonsdorfer
J
J
D000328:Adult; D002302:Cardiac Output / Q000502:physiology*; D002307:Cardiography, Impedance / Q000295:instrumentation* / Q000592:standards; D005080:Exercise Test / Q000295:instrumentation* / Q000592:standards; D006801:Humans; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D015203:Reproducibility of Results
D010100:Oxygen