Comparison of FloTrac cardiac output monitoring system in patients undergoing coronary artery bypass grafting with pulmonary artery cardiac output measurements.

BACKGROUND: Arterial pulse waveform analysis has been proposed for cardiac output (CO) determination and monitoring without calibration or thermodilution (FloTrac/Vigileo; Edwards Lifesciences, Irvine, CA, USA). The accuracy and clinical applicability of this technology has not been fully evaluated. We designed this prospective study to compare the accuracy of the FloTrac system (CO(FT)) vs. pulmonary artery catheter standard bolus thermodilution (CO(PAC) ) in patients undergoing coronary artery bypass grafting.

METHODS: We studied 11 patients referred for coronary artery bypass grafting. CO(FT) and CO(PAC) were determined at six time points in the operating room including before and 5 min after volume expansion (500 mL 6% hetastarch). Measurements were performed on arrival in the intensive care unit and every 4 h afterwards. Bland-Altman analysis was used to assess the agreement between CO(FT) and CO(PAC).

RESULTS: CO(PAC) ranged from 2.0 to 7.6 L min-1 and CO(FT) ranged from 1.9 to 8.2 L min-1. There was a significant relationship between CO(PAC) and CO(FT) (r = 0.662; P < 0.001). Agreement between CO(PAC) and CO(FT) was -0.26 +/- 0.87 L min-1. Volume expansion induced a significant increase in both CO(PAC) and CO(FT) (from 3.4 +/- 0.8 to 4.4 +/- 1.0 L min-1; P < 0.001 and from 3.9 +/- 1.2 to 5.0 +/- 1.1 L min-1; P < 0.001, respectively) and there was a significant relationship between percent change in CO(PAC) and CO(FT) following volume expansion (r = 0.722; P = 0.01).

CONCLUSION: We found clinically acceptable agreement between CO(FT) and CO(PAC) in this setting. This new device has potential clinical applications.