Comparison of the Ability of the esCCO and the Volume View to Measure Trends in Cardiac Output During Cardiac Surgery

Cardiac output (CO) is a major physiological variable that should be monitored closely during cardiac surgery in order to assess and guide therapeutic interventions so as to decrease postoperative morbidity. The purpose of this study was to compare CO measured by two easy to use non-invasive monitors, the esCCO (Nihon Kohden, Tokyo, Japan) to the Volume View (Edwards Lifesciences, Irvine, USA) and to assess their trending ability in patients undergoing cardiac surgery. After Internal review board approval and written informed consent, 19 patients were included in this study. Before cardiopulmonary bypass (CPB), CO was measured simultaneously using both the esCCO and the Volume View device before and after 3 CO-modifying maneuvers [passive leg raise (PLR), end expiratory occlusion test (EEOT) and positive end expiratory pressure (PEEP) at 10 cm H2O. Five CO values for esCCO and three for volume view were averaged and compared during a one minute period of time before and after each maneuver. The precision error and its 95% confidence interval (CI) that corresponds to the least significant change (LSC) were calculated within this period of time. The Bland-Altman analysis was used to compare bias, precision and limits of agreement (LOA) of both devices. Trending ability of CO changes was assessed by a modified 4 quadrant plot analysis, within angular limits of agreement considered as acceptable when the mean angle between both delta CO was less than 30°.