Pulse contour cardiac output: an evaluation of the FloTrac method

Background and objective The aim of this study was to determine the agreement between pulmonary artery thermodilution (PA-TD) and a new pulse contour method (PCM) FloTrac/Vigileo version 1.0, and to asses the ability of FloTrac to track sudden changes in cardiac output. Methods Cardiac output was determined twice after induction of anaesthesia, but before cardiac surgery, with both PA-TD and a PCM in order to determine the precision of both methods. The bias and agreement between the two methods were calculated using Bland-Altman analysis. Postoperatively, in patients with heart rates under 60 beats min(-1), atrial pacing was initiated and cardiac output was determined before and after with both methods. Results Twenty-five patients were investigated. The precisions of PA-TD and the PCM were 0.35 (95% confidence interval +/-0.12) and 0.6 l min(-1) (95% confidence interval +/-0.21%). The bias between PA-TD and the PCM was -0.51 l min(-1) and the limits of agreement were +/-1.87 l min(-1) (95% confidence interval +/-0.39 and +/-0.66). The percentage error was 48%. The changes in cardiac output with atrial pacing were in the same direction in all nine patients. Conclusion In this study, agreement between PA-TD and the PCM was poor, but the PCM was able to track the direction of pace-induced changes in cardiac output. Eur J Anaesthesiol 26:484-489 (C) 2009 European Society of Anaesthesiology.