Uncalibrated Continuous Cardiac Output Measurement in Liver Transplant Patients: LiDCOrapid System versus Pulmonary Artery Catheter

Objective: The aim of the study was to assess the level of agreement between continuous cardiac output estimated by uncalibrated pulse-power analysis (PulseCOLiR) and intermittent (ICO) and continuous cardiac output (CCO) obtained using a pulmonary artery catheter (PAC). Design: Prospective cohort study. Setting: University hospital intensive care unit. Participants: Twenty patients after liver transplantation. Intervention: Pulmonary artery catheters were placed in all patients, and ICO and CCO were determined using thermodilution. PulseCOLiR measurements were made using a LiDCOrapidTM (LiDCO Ltd, Cambridge, UK). Measurements and Main Results: ICO data were deter- mined after intensive care unit admission and every 8 hours until the 48th postoperative hour. CCO and PulseCOLiR measurements were recorded simultaneously at these same time intervals as well as hourly. For the 8-hour data set (140 data pairs), the mean bias and percentage errors (PE) were, respectively, 0.10 L/min and 39.2% for ICO versus Pulse- COLiR and 0.79 L/min and 34.6% for CCO versus PulseCOLiR. For the hourly comparison of CCO versus PulseCOLiR (980 data pairs), the bias was 0.75 L/min and the PE 37%. To assess the ability to measure change, a 4-quadrant plot was produced for each pair of methods. The performance of PulseCOLiR was moderate in detecting changes in ICO. Conclusions: In conclusion, the uncalibrated PulseCOLir method should not be used as a substitute for the thermo- dilution technique for the monitoring of cardiac output in liver transplant patients.