Study objective: To evaluate the ability of arterial waveform contour analysis to measure cardiac output (CO) continuously in postoperative critically ill patients.
Design: Thermodilution CO (TDCO) measurements were compared with simultaneous pulse contour CO (PCCO) measurements.
Setting: University hospital surgical intensive care unit.
Patients: 29 critically ill surgical patients with indwelling systemic arterial and pulmonary artery catheters.
Measurements and main results: TDCO measurements were compared with PCCO at 1- to 2-hour intervals. Mean TDCO was 5.75 +/- 1.79 L/min, and mean PCCO was 5.76 +/- 1.83 L/min. Analysis of the difference between TDCO and PCCO showed a bias of 0.01 +/- 0.5 L/min. Comparison of the difference between pairs of sequential TDCO measurements and the initial TDCO and subsequent PCCO measurements resulted in a correlation coefficient of 0.64.
Conclusions: The PCCO method appears to be able to estimate changes in CO under the conditions tested, in which PCCO was recalibrated after each TDCO measurement. However, limitations of this method in the immediate postoperative period following aortic aneurysm surgery were identified.