2013 Volume 83 Issue 3 Pages 273-282
A new technology called estimated continuous cardiac output (esCCO) uses pulse wave transit time (PWTT) obtained from an electrocardiogram and pulse oximeter to measure cardiac output (CO) noninvasively and continuously. This study was performed to evaluate the accuracy of esCCO during exercise testing. We compared esCCO with CO measured by echo Doppler aortic velocity-time integral (VTIao_CO). The correlation coefficient between esCCO and VTIao_CO was r = 0.87 (n = 72). Bias and precision were 0.33 ± 0.95 L/min with a percentage error of 30.2%. And the correlation coefficient between change in esCCO and change in VTIao_CO was r = 0.75 (n = 70). The esCCO could detect change in VTIao_CO larger than 1 L/min with a concordance rate of 88.2%. The areas under ROC curves to detect VTIao_CO changes more than 15% and 30% were 0.81 and 0.91, respectively. Polar plots show that the mean polar angle was 2.2° and radial limits of agreement were ±43.6°. The trending ability of esCCO is comparable with that of currently available arterial waveform analysis methods. In this study, the validity of esCCO during exercise testing was assessed and shown to be acceptable with respect to agreement and trending ability compared with the echo Doppler.