[Comparison of ICG thoracic bioimpedance cardiac output monitoring system in patients undergoing cardiac surgery with pulmonary artery cardiac output measurements].

OBJECTIVE: Thoracic bioimpedance has been proposed for cardiac output (CO) determination and monitoring without calibration or thermodilution (ICG Monitor 862146, Philips Medical System, Philips, Suresnes, France). The accuracy and clinical applicability of this technology has not been fully evaluated in the cardiac surgery setting. We designed this prospective study to compare the accuracy of the ICG Monitor (CO(ICG)) versus pulmonary artery catheter standard bolus thermodilution (CO(PAC)) in patients after cardiac surgery or having benefited from cardiac surgery.

STUDY DESIGN: Prospective, monocentric.

MATERIAL AND METHODS: We studied 13 patients in the postoperative period. CO(ICG) and CO(PAC) were determined at the arrival in the intensive care unit and every four hours. Bland-Altman and Critchley and Critchley's analysis were used to assess the agreement between CO(ICG) and CO(PAC).

RESULTS: CO(PAC) ranged from 2.6 to 11.0 l/min and CO(ICG) ranged from 1.8 to 11.7 l/min. There was a significant relationship between CO(PAC) and CO(ICG) (r=0.61 ; p<0.001). Agreement between CO(PAC) and CO(ICG) was -0.5+/-1.3 l/min (Bland-Altman analysis). Percentage error between the two methods was 49% (Critchley and Critchley's analysis).

CONCLUSION: We found clinically unacceptable agreement between CO(ICG) and CO(PAC) in this setting. Despite its non invasiveness, this device cannot be recommended for CO monitoring in the postoperative period following cardiac surgery.