Continuous cardiac output measurement: pulse contour analysis vs thermodilution technique in cardiac surgical patients

We have analysed the clinical agreement between two methods of continuous cardiac output measurement pulse contour analysis (PCCO) and a continuous thermodilution technique (CCO), were both compared with the intermittent bolus thermodilution technique (BCO). Measurements were performed in 26 cardiac surgical patients (groups 1 and 2, 13 patients each, with an ejection fraction > 45% and < 45%, respectively) at 12 selected times. During operation, mean differences (bias) between PCCO-BCO and CCO-BCO did not differ in either group. However, phenylephrine-induced increases in systemic vascular resistance (SVR) by approximately 60% resulted in significant differences. Significantly higher absolute bias values of PCCO-BCO compared with CCO-BCO were also found early after operation in the ICU. Thus PCCO and CCO provided comparable measurements during coronary bypass surgery. After marked changes in SVR, further calibration of the PCCO device is necessary.