Correlation of cardiac output measured by non-invasive continuous cardiac output monitoring (NICOM) and thermodilution in patients undergoing off-pump coronary artery bypass surgery

PURPOSE: This observational study was designed to evaluate the clinical value of cardiac output (CO) obtained via bioreactance (NICOM™) as compared with values of CO obtained via thermodilution (using pulmonary artery catheter, Vigilance™) and the thoracic bioimpedance (BioZ.com™), in patients undergoing off-pump coronary artery bypass surgery. METHODS: Fifty American Society of Anesthesiologists physical status I–III patients, aged 38–81 years, scheduled for off-pump coronary artery bypass surgery were enrolled in this study. CO data (NCO, BCO, PCO) were recorded during the operative period at ten time points after stable hemodynamic conditions were achieved. RESULTS: The equation of the relationship between the PCO and NCO is PCO = 0.945 × NCO + 0.328 (r = 0.77), and that of PCO and BCO is PCO = 0.965 × BCO + 0.729 (r = 0.63). Furthermore, no statistical difference was found between PCO versus NCO (mean (SD): 4.4 (1.1) versus 4.4 (0.9), p = 0.431). A significant correlation was found between PCO and NCO (r = 0.77, p < 0.001). Correlation was also found between PCO and BCO (r = 0.63, p < 0.001). CONCLUSIONS: The NICOM device is a safe, convenient, and reliable device for measuring continuous non-invasive cardiac output and cardiac index, and the trends of change in CO during the surgery are similar between NICOM and PAC.