Estimating cardiac output from arterial blood pressure waveforms: A critical evaluation using the MIMIC II database

Cardiac output (CO) estimation using arterial blood pressure (ABP) waveforms has been an active area of physiology research over the past century. However, the ef-fectiveness of the estimators has not been extensively stud-ied in a clinical setting. In this paper, we evaluate 11 well-known CO estimators using clinical radial ABP waveforms from the Multi-Parameter Intelligent Monitoring for Inten-sive Care II (MIMIC II) database, using thermodilution CO (TCO) as reference for comparison. We compare esti-mations to 988 TCO measurements in 84 patients, totaling 165 hours of ABP waveforms sampled at 125 Hz. As a nec-essary step for producing absolute CO estimates, we also present 3 methods of calibrating the estimators, each tai-lored towards a different use model. The results show that the standard deviation of error between TCO and the best CO estimators is approximately 1 L/min for absolute CO estimates. For relative estimates without calibration, the best CO estimator has 18 % error at 1 standard deviation. 1