Original Article

Clinical Comparisons of Continuous Venous Oxygen Saturation and Hematocrit Monitors in Pediatric Surgery

Department of Cardiovascular Perfusion, Children's Hospital, Columbus, Ohio

^* Address correspondence to: Denise Bennett, BS, CPT, Cardiovascular Perfusion, J-260, Children's Hospital, 700 Children's Drive, Columbus, OH 43205

Abstract

Continuous venous oxygen saturation and hematocrit values are important parameters in assessing patient status while on cardiopulmonary bypass. Two devices used to measure continuous venous oxygen saturation while on cardiopulmonary bypass were compared to a control. The Bentley Oxysat meter and the Medtronic MX2 Oxygen Saturation and Hematocrit System were compared to the ABL500 blood gas monitor. The continuous hematocrit readings from the MX2 system were compared to spun hematocrits. Twenty-nine pediatric patients ranging from 2.3kg - 43.3kg were randomly selected. In-line optical transmission cells used were 1/4" or 3/8" depending upon the patient's blood tlow requirements. A total of 163 data points were analyzed at different blood flow rates, temperatures, and hematocrits. The venous oxygen saturation values obtained from the Oxysat and the MX2 devices correlated well with the ABL500 over the entire range of blood flows, temperatures, and hematocrits. All correlation coefficients were greater than 0.89. The correlation betweeen the MX2 device and the spun hematocrit varied with temperature ranges. The correlation coefficient tended to decrease with decreasing temperature. We conclude that these devices are important adjuncts to bypass as long as their limitations are understood.