Background and Goal of Study: High-risk patients undergoing major surgery may benefit from accurate measurement of cardiac output (CO) during the perioperative period. The goal of this study was to compare CO measurements by FloTrac/Vigileo (COFT) and PRAM/Mostcare (COMC) versus aortic Doppler flow (COAD) using transesophageal echocardiography (TEE) in patients undergoing coronary artery bypass surgery.
Materials and Methods: After approval of ethical review board, all consecutive patients scheduled for coronary artery bypass grafting were included. Exclusion criteria were: cardiac rhythm disturbances, aortic valve disease, significant subclavian artery stenosis and contraindication for TEE use.  Simultaneous CO measurements were performed after induction of anesthesia (T1), before cardiopulmonary bypass (CPB) (T2), after CPB (T3) and at end of surgery (T4). For the comparison of CO measurements Bland-Altman method was applied(1). The percentage of error (PE) was calculated as described by Critchley and Critchley. We considered a PE of 30% limit as acceptable. 
Results and Discussion: A total of 189 pairs of measures of 27 patients were analyzed (6.96+/-1.3; 3 to 8 per patient). For COFT vs COAD , the bias was -0.524 liter min-1 (IC 95% -2.88 to 1.83), precision 1±0,84 liter min-1 and PE 54.89%. For COMC vs COAD the bias was -0.015 liter min-1 (IC 95% -2.993 to 2.963), precision 1.16±0.98 litre min-1 and PE 73.94%. 
Conclusion: COFT and COMC measurements showed a high percentage of error compared with COAD in patients undergoing coronary artery bypass grafting.
References: 
(1)Odor PM et al. Cardiac Output Monitoring: Validation Studies–how Results Should be Presented.Curr Anesthesiol Rep (2017) 7:410–415

07 / Comparison between CO measurement methods on cardiac bypass grafting surgery: uncalibrated pulse wave analysis vs aortic Doppler.