Systemic effects of multidose hypothermic potassium cardioplegia.

The purpose of this study was to investigate the changes in serum and urine potassium before, during, and after the administration of potassium cardioplegia using a solution containing 28 mEq/L of potassium chloride in 20 consecutive patients with acquired heart disease. The data obtained suggest that the concentration of potassium administered does not result in inordinately elevated serum potassium levels (peak, 4.6 +/- 0.18 mEq/L at 2 hours of multidose hypothermic potassium cardioplegia) during or after infusion. Additionally, the urinary excretion of potassium increased during infusion and eventually exceeded the amount of potassium infused. While hypothermic potassium cardioplegia appears to be a safe and efficient method of myocardial protection, continued surveillance of postoperative potassium levels remains necessary to detect obligatory urinary potassium excretion following cardiopulmonary bypass and operation.