Cardiac output measured by uncalibrated arterial pressure waveform analysis by recently released software version 3.02 versus thermodilution in septic shock

To evaluate the 3.02 software version of the FloTrac/Vigileo (TM) system for estimation of cardiac output by uncalibrated arterial pressure waveform analysis, in septic shock. Nineteen consecutive patients in septic shock were studied. FloTrac/Vigileo (TM) measurements (COfv) were compared with pulmonary artery catheter thermodilution-derived cardiac output (COtd). The mean cardiac output was 7.7 L min(-1) and measurements correlated at r = 0.53 (P < 0.001, n = 314). In Bland-Altman plot for repeated measurements, the bias was 1.7 L min(-1) and 95 % limits of agreement (LA) were -3.0 to 6.5 L min(-1), with a %error of 53 %. The bias of COfv inversely related to systemic vascular resistance (SVR) (r = -0.54, P < 0.001). Above a SVR of 700 dyn s cm(-5) (n = 74), bias was 0.3 L min(-1) and 95 % LA were -1.6 to 2.2 L min(-1) (%error 32 %). Changes between consecutive measurements (n = 295) correlated at 0.67 (P < 0.001), with a bias of 0.1 % (95 % limits of agreement -17.5 to 17.0 %). All changes > 10 % in both COtd and COfv (n = 46) were in the same direction. Eighty-five percent of the measurements were within the 30A degrees aEuro"330A degrees of the polar axis. COfv with the latest software still underestimates COtd at low SVR in septic shock. The tracking capacities of the 3.02 software are moderate-good when clinically relevant changes are considered.