Continuous, less invasive, hemodynamic monitoring in intensive care after cardiac surgery

A pulse-contour-based method for continuous measurement of cardiac output (CO) and systemic vascular resistance (SVR) was tested and arterial thermodilution, used for calibration, was compared to pulmonary artery thermodilution. In 30 patients CO and SVR were measured by pulse contour analysis (COpc, SVRpc) 270 times in 24 h and compared to arterial (COart, SVRart) and pulmonary arterial (COpa, SVRpa) thermodilution measurements. The mean difference between COpa and COart was 0.26 L/min (3.6%) with a standard deviation (SD) of 0.7 L/min, the correlation coefficient was 0.96, and the coefficient of variation was 5.0% and 5.9% respectively. COpc did differ from COpa by 0.11 L/min (1.5%, SD = 0.6 L/min) and from COart by 0.15 L/min (2.1 %, SD = 0.7 L/min). Correlation of COpc with COpa was 0.91, correlation of COpc with COart was 0.90. SVRpc did correlate with SVRpa, a coefficient of 0.94, and with SVRart, a coefficient of 0.92. Mean COpc and SVRpc did not differ significantly from COpa or COart and SVRpa or SVRart during the 24 h study period. It is concluded that COart correlates well with COpa and can be used to calibrate COpc. COpc and SVRpc agree with thermodilution-based CO and SVR without recalibration for 24 hours.