Background and Goal of Study: 
Intraoperative hemodynamic optimization based on cardiac output (CO) monitoring may improve outcome of high-risk patients undergoing major surgery. The FloTrac/VigileoTM  (FTV) is a device that allows continuous CO determination and that has gained popularity in the last few years for monitoring high-risk patients in the intraoperative  setting.  The fact that it doesn´t requires previous calibration can be an advantage but previous studies showed that it may be a drawback in some clinical settings. The goal of this study was to evaluate the agreement between CO measured by FTV system (COFT) and CO measured by aortic Doppler flow (COAD) using transesophageal echocardiography (TEE) in patients undergoing coronary artery bypass grafting.

Materials and Methods: 
30 patients were enrolled. Exclusion criteria were: cardiac rhythm disturbances, aortic valve disease, known subclavian artery stenosis or contraindication for TEE use. CO measurements were simultaneously collected at different times of surgery. Bland-Altman analysis was used to compare COFT  (software 4.0) with COAD measurements. 

Results and discussion: 
A total of 190 pairs of CO measures were analysed. Bias was -0,47 litre min-1,(95% IC ±2,03) precision was 0,87 ± 0,73 litre min-1 and percentage of error was 48%. 

Conclusion: 
Despite the upgraded algorithm, the CO measured by the FTV device still showed a high percentage of error compared with CO measured by aortic Doppler flow using TEE in  patients undergoing coronary artery bypass grafting.

Measurement of cardiac output in coronary artery bypass grafting FloTrac/VigileoTM vs Aortic Doppler