The Accuracy of the Vigileo/FloTrac Continuous Cardiac Output Monitor

Objective: The Vigileo/FloTrac system (software version 1.01; Edwards Lifesciences, Irvine, CA) determines cardiac output, without calibration, by analysis of the arterial pulse wave. To assess the accuracy of the Vigileo/FloTrac system, it was compared with the pulmonary artery catheter bolus thermodilution method as the current standard method. The study design was prospective and observer blinded.

Setting: A single university hospital.

Participants: Thirty elective coronary artery bypass graft surgery patients. No special interventions were done to the participants.

Measurements and Main Results: After approval by the ethics committee and with written informed consent, synchronized measurements using both methods were made at 7 predefined time points, intraoperatively and postoperatively, producing 192 data pairs for evaluation. The statistical evaluation was performed by using the Bland-Altman method of analysis. In addition, a ±20% and ±30% deviation from the pulmonary artery catheter were evaluated (20% criteria and 30% criteria). In total, 46% of measurements did not fulfill the 20% criteria; 26% were outside the 30% limits. The Bland-Altman analysis for all time points showed that 95% of all differences between both methods were within a range between −2.2 and +3.1 L/min. Regression analysis revealed low correlation values at all time points.

Conclusion: The described deviation from the standard must be regarded according to the user's needs. Considering the 30% limits of agreement, the Vigileo system (version 1.01) seems sufficiently accurate; applying the 20% criteria, it is not.

Key words: cardiac output, accuracy, Vigileo, FloTrac