Off-pump coronary artery bypass (OPCAB) patients often require fluid, vasopressor, or inotropic support. It is therefore important that vigilant monitoring be undertaken to guide intervention and monitor the effects of therapy. Continuous monitoring of cardiac output (CO) is advisable. The aim of this study was to compare continuous cardiac index (CCI) and stat cardiac index (SCI) with intermittent bolus cardiac index (ICI) in patients undergoing OPCAB surgery.

Matched sets of CI measurements among CCI, SCI, and ICI were collected in 35 patients undergoing elective OPCAB at specific time periods. Bland-Altman analysis was used to compare the agreement among the different methods.

Bland-Altman analysis of CI measurements yielded a bias, precision, and percent error of 0.09 ± 0.63 L/min/m² (46.2%) for CCI and 0.09 ± 0.60 L/min/m² (44.0%) for SCI, compared with ICI measurements.

We found that the agreement of CCI, SCI, and ICI was poor. This disagreement increased during periods of open thorax and open pericardium when compared to the period of closed thorax. Continuous CO measurements through pulmonary artery catheter should be interpreted with caution during OPCAB.