Cardiac output derived from arterial pressure waveform analysis: Validation of the third-generation software in patients undergoing orthotopic liver transplantation

Background: The upgraded third-generation software (version 3.02) for the FloTrac/Vigileo system has been developed to particularly improve the accuracy of cardiac output (CO) measurements in hyperdynamic conditions. The aim of our study was to compare the CO values obtained using the FloTrac/Vigileo system during orthotopic liver transplantation (OLT) with those obtained in the same circumstances using a Swan-Ganz catheter (bolus thermodilution method). Methods: Twenty consecutive recipients scheduled for OLT were studied. Simultaneous CO values measured by both devices were obtained at 10 predefined time points throughout the surgery. A percentage error of not more than 30% was established as the criterion for device interchangeability. Results: A total of 200 paired measurements were obtained. The CO values derived from the FloTrac/Viligeo ranged from 2.8 to 10.9 L/min, with a mean of 5.91 ± 1.81 L/min. The values from bolus thermodilution ranged from 2.2 to 13.2 L/min, with a mean of 6.12 ± 2.07 L/min. The bias was 0.22, and the limits of agreement were -3.13 to 3.56 L/min. The percentage error between the FloTrac/Viligeo and bolus thermodilution measurements was 54.93%. The percentage errors of paired measurements in three surgical phases by subgroup analysis were 43.50% (dissecting phase), 62.9% (anhepatic phase), and 56.05% (reperfusion phase), respectively. Conclusion: CO measurements obtained using the less invasive arterial waveform FloTrac/Vigileo system upgraded with the third-generation software had poor intraoperative agreement with pulmonary artery thermodilution CO measurements in patients undergoing OLT.