Accuracy of noninvasive estimated continuous cardiac output (esCCO) compared to thermodilution cardiac output: a pilot study in cardiac patients.

OBJECTIVE: To compare the noninvasive estimated continuous cardiac output (esCCO), device-derived cardiac output (CO) to simultaneous pulmonary artery catheter (PAC) thermodilution (TD) CO. DESIGN: A prospective study comparing pulse wave transit time (estimated continuous cardiac output, esCCO; Nihon Kohden, Tokyo, Japan) to intermittent TD CO. SETTING: One academic hospital. PARTICIPANTS: Patients presenting for cardiac surgery. INTERVENTIONS: Intraoperative CO measurements at 4 distinct time points (after induction, after sternotomy, after cardiopulmonary bypass, and after chest closure). MEASUREMENTS AND MAIN RESULTS: The study population consisted of American Society of Anesthesiologists (ASA) IV subjects, 27 (77%) males and 8 (23%) females, with a mean age of 64.6 ± 12.2 years. Data points from esCCO and TD were collected simultaneously and means per time point compared using Bland-Altman, Pearson R coefficient, and percent error. Mean TD CO for the study was 5.4 L/min. The Pearson R coefficient, percent error, and bias in L/min were: 0.57, 44%, 0.66 (after induction); 0.54, 51%, 0.88 (after sternotomy); 0.60, 60%, 0.95 (after cardiopulmonary bypass); and 0.57, 60%, 0.75 (after chest closure) respectively. CONCLUSIONS: esCCO is easy to use and provides continuous CO measurements, but has wide limits of agreement and large percentage errors with a consistently positive bias in comparison to TD.

Comparison of the endotracheal cardiac output monitor to thermodilution in cardiac surgery patients.

OBJECTIVES: 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. DESIGN: Prospective study. SETTING: One academic hospital. PARTICIPANTS: Forty volunteer patients undergoing cardiac surgery. INTERVENTIONS: Intraoperative CO measurements. MEASUREMENTS AND MAIN RESULTS: 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%. CONCLUSIONS: ECOM did not adequately agree with TD in patients undergoing cardiac surgery.