Inaccuracy of the FloTrac/Vigileo™ System in Patients With Low Cardiac Index

Objectives: The goal of this study was to compare cardiac output derived from the FloTrac/Vigileo (TM) system (COFT) with cardiac output measured by 3-dimensional transesophageal echocardiography (CO3D) in patients with severe heart failure undergoing cardiac resynchronization therapy. The impact of preoperative systemic vascular resistance index on the accuracy of the FloTrac/Vigileo (TM) system also was investigated. Design: Prospective clinical study. Setting: Cardiac surgery operating room of a single cardiovascular center. Participants: Forty-one patients undergoing elective cardiac resynchronization therapy lead implantation. Interventions: CO3D as the reference method and COFT were determined simultaneously after induction of anesthesia. Measurements and Main Results: Linear regression analysis showed a poor correlation between CO3D and COFT(R-2 = 0.16). Bland-Altman plots showed wide limits of agreement between CO3D and COFT. Bias was 0.60 +/- 0.63 L/min with a high percentage error of 58.2%. Subgroup analysis showed that the percentage error between CO3D and COFT was 74.1% in patients with a cardiac index <2.2 L/min/m(2) and 17.2% in patients with a cardiac index >= 2.2 L/min/m(2). Systemic vascular resistance index was significantly higher in patients with a cardiac index <2.2 L/min/m(2) (3,037 +/- 820 v 2,461 +/- 878; p = 0.039). Conclusions: The FloTrac/Vigileo (TM) system is not accurate in patients with low cardiac output, especially those with a cardiac index <2.2 L/min/m(2). A high systemic vascular resistance index in patients with low cardiac index may contribute to this inaccuracy. (C) 2014 Elsevier Inc. All rights reserved.