Comparison of the Endotracheal Cardiac Output Monitor to Thermodilution in Cardiac Surgery Patients

Abstract

To compare cardiac output (CO) measurements from a novel endotracheal bioimpedance cardiac output monitor device (ECOM; ConMed, Irvine, CA) to simultaneous pulmonary artery thermodilution (TD) CO. Prospective study. One academic hospital. Forty volunteer patients undergoing cardiac surgery. Intraoperative CO measurements. Simultaneous comparative data points were collected from ECOM and TD at 4 periods: post-induction, post-sternotomy, post-cardiopulmonary bypass, and post-chest closure. The mean CO(TD) was compared with CO(ECOM) for each operative period then assessed for agreement by linear regression, Bland-Altman analysis, and percent error methods. There were 35 men (87.5%) with a mean age of 66 ± 10.7 years in the present study population. R values (p value) for the 4 time periods were 0.50 (0.002), 0.33 (0.035), 0.42 (0.007), and 0.48 (0.002). Bias and 95% limits of agreement in L/min were -0.11 (-2.40 to 2.18), 0.04 (-2.57 to 2.65), -0.06 (-2.86 to 2.74), and 0.02 (-2.42 to 2.45). Percent errors of the 4 time periods were 51%, 53%, 50%, and 48%. ECOM did not adequately agree with TD in patients undergoing cardiac surgery.