Evaluation of the Fourth-Generation FloTrac/Vigileo System in Comparison With the Intermittent Bolus Thermodilution Method in Patients Undergoing Cardiac Surgery.

OBJECTIVES: The aim of this study was to evaluate the accuracy, precision, and trending ability of the fourth-generation FloTrac/Vigileo system (version 4.00; Edwards Lifesciences, Irvine, CA) by comparing cardiac output derived from FloTrac/Vigileo system (COAP ) with that measured by a pulmonary artery catheter (COTD ), and to determine the effects of hemodynamic variables on the bias between COTD and COAP .

DESIGN: A prospective study.

SETTING: University hospital.

PARTICIPANTS: Thirty patients undergoing elective cardiac surgery using cardiopulmonary bypass.

INTERVENTIONS: Including hemodynamic variables, COTD and COAP were measured simultaneously at the following 10 time points: after the induction of anesthesia, at the start of operation, after sternotomy, before and after the administration of heparin, before and after the administration of protamine, at the start of sternal closure, at the end of operation, and on arrival to intensive care unit.

MEASUREMENTS AND MAIN RESULTS: In total, 280 pairs of datasets were obtained. Bland-Altman analysis showed a bias of -0.41 L/min, a precision of 0.72 L/min, and limits of agreement of -1.85 and 1.03 L/min, with a percentage error of 37.1%. The concordance rate determined by 4-quadrant plot analysis and the polar concordance rate were 76% and 79%, respectively. The linear mixed-effect model revealed that the bias was influenced strongly by the difference in pulse pressure between the radial and femoral artery (p < 0.001), and the systemic vascular resistance index (p < 0.001).

CONCLUSION: The fourth-generation FloTrac/Vigileo system still lacks accuracy and trending ability in cardiac surgery, and the discrepancy in cardiac output measurement depends on the peripheral vascular tone. Further improvement of this system is needed.