1997 OPEN FORUM Abstracts
COMPARISON OF ESOPHAGEAL DOPPLER AND THERMAL DILUTION CARDIAC OUTPUT IN CRITICAL CARE PATIENTS
Paul Loik RRT, Allan Andrews MS, RRT, Linda Folk RRT, Lauren Stapp RRT, Ron Dechert MS, RRT, Shari Bailey RRT- Critical Care Support Services-University of Michigan Medical Center- Ann Arbor, Michigan.
Introduction: Hemodynamic monitoring is an important adjunct to therapeutic support of the critical care patient. The use of pulmonary artery catheters have been an integral part of hemodynamic monitoring to allow assessment of fluid status and cardiac performance. Recent criticism of PA catheters have questioned the efficacy of this monitor. Esophageal doppler technology may provide functional assessment of hemodynamic status with little or no risk for the critically ill patient. A new esophageal doppler monitor (EDM, Deltex Medical Incorporated, Irving Tx) has been introduced to provide continuous hemodynamic monitoring in patients who may not warrant PA catheters. The purpose of this study was to evaluate the bias and error of cardiac output monitoring using the EDM system. Methods: Patients who required PA catheters and CO measurements as part of their routine clinical management were selected. Sixteen patients were originally recruited for this study. Three patients were excluded from final analysis due to signal distortion. Thirteen nonrandomized mechanically ventilated adult patients were selected for this comparison trial. An EDM probe was placed according to the manufacturers guidelines. Nasal placement was the preferred route whenever possible. The cardiac output values obtained from the EDM were compared to values obtained from thermal dilution cardiac output measurements taken at the same time. A total of 24 comparisons were obtained from this study population. Bias and error were determined using the statistical analysis described by Bland and Altman. The results are presented in the following discussion. Results: We found excellent correlation between the cardiac output values obtained from the EDM when compared against our clinical standard, bolus thermal dilution. The observed correlation was r2=0.74, p < 0.05. The bias (EDM-TD) and error observed were 0.125 L/min and 1.18 L/min respectively. The mean cardiac output for all comparative results was 5.85 L/min with a range of 2.8 to 10.95 (EDM+TD / 2) L/min. Conclusions: The Deltex EDM provides comparable values as those reported by TD in critical care patients. In addition, the EDM allows continuous monitoring of flow which may allow improved therapeutic assessment.