Comparison of cardiac output measurements obtained through thermo dilution method and arterial pressure wave analysis in patients undergoing cardiopulmonary bypass graft surgery

Background: In this study we aimed to determine the accuracy and reliability of the FloTrac/Vigileo system by comparing cardiac output measurements obtained simultaneously from the FloTrac/Vigileo system and the gold standard thermodilution technique at different periods during cardiac arterial bypass graft (CABG) surgery. Methods: After ethics committee approval, 22 patients in the ASA II group who were planned for CABG surgery were included in the study. Cardiac output, stroke volume, heart rate and cardiac index values obtained from the FloTrac/Vigileo system and the thermodilution method were simultaneously recorded during different cardiac bypass periods. These periods were as follows: T1: the first measurement after pulmonary artery catheter insertion; T2: at the time of left internal mammary artery (LIMA) extraction; T3: before cannulation; T4: immediately after releasing the cross-clamp; T5: during warming patient's blood to 33 degrees C; T6: during warming patient's blood to 35 degrees C; T7: at 36.5 degrees C before removing the patient from bypass; T8: after the patient was removed from bypass; T9: after the sternum was closed. All data were transferred into SPSS version 16.0 software and evaluated with the Bland-Altman analysis and the Pearson correlation tests. Results: The mean cardiac output values obtained from both measurement techniques at T1, T2, T3 and T9 periods and the mean cardiac index values obtained from both measurement techniques at T1, T2, T3, T8 and T9 periods were found to be within the 95% confidence interval. Moreover, when the cardiac output and cardiac index measurement results were compared, the FloTract/Vigileo and thermodilution methods showed a good level of accordance and positive correlation at these periods. But no correlation was found for cardiac index at the T7 period. Conclusion: While there is a need for more studies on more complicated conditions and in patients receiving inotropic support, we concluded that FloTract/Vigileo system, which provides the advantages of ease of use and less invasiveness, is a good choice for determining cardiac output in patients who will have cardiac surgery and in patients with cardiac risk who will have non-cardiac surgery.