Proceedings

Oxygen Content: Measured versus Calculated Values in Hypothermic Cardiopulmonary Bypass

Circulation Technology Division, School of Allied Medical Professions, College of Medicine, The Ohio State University, Columbus, Ohio

^* Address correspondence to: Beth Pfaender, Harper-Grace Hospital, Perfusion Services Department, 3990 John R., Detroit, Michigan, 48201.

Abstract

Various formulae and methods have been utilized to arrive at blood oxygen content values, often disregarding effects of p50 shifts due to temperature and other factors on the oxyhemoglobin dissociation curve. This study seeks to compare direct oxygen content measurements utilizing a galvanic fuel cell with traditional methods of blood gas analysis and co-oximetry. Several standard formulae and methods were applied to arrive at oxygen content and consumption which were compared with the values obtained by direct measurement. Several indirect methods appeared to approximate the oxygen content values as directly measured. When applied to oxygen consumption calculations, the data points became widely scattered. Sources of error appear to lie in the application of temperature corrected blood gas data to a 37°C oxyhemoglobin dissociation curve.