PHYSIOLOGY AND REGULATION - IONIZED CALCIUM, MAGNESIUM AND LACTATE MEASUREMENTS IN CRITICAL CARE SETTINGS

The biochemical and physiologic bases for clinical use of ionized calc ium, magnesium, or lactate measurements are described, with emphasis o n the critical care setting. lonized calcium or magnesium are usually measured to prevent hypocalcemia or hypomagnesemia, conditions that mo st affect cardiovascular function. Blood lactate measurements have bee n used more frequently in the last 5 years, despite decreases in overa ll laboratory test volume. Lactate measurements appear to have clinica l value, particularly for children having major cardiac surgery or ext racorporeal membrane oxygenation. The changes in test volumes in the p ast few Sears due to tile changing economic climate in medical practic e are also described.