Case Report

The Use of a Hemoconcentrator for Management of Sudden Acute Hyperkalemia During Hypothermic Cardiopulmonary Bypass

Professor and Director, Cardiovascular Anesthesia Department of Anesthesia, University of South Alabama, Mobile, Alabama

^* Address correspondence to: David A. Cross, MD, Department of Anesthesia, University of South Alabama, Mobile, Alabama 36617

Abstract

A case is presented of a 64-year-old male undergoing saphenous vein coronary artery grafting. With application of the aortic cross-clamp and infusion of antegrade cardioplegia, unexpectedly severe aortic insufficiency caused the majority of the cardioplegic solution to enter the left ventricle and be returned to the oxygenator reservoir via the left ventricular sump. A total of 5,600 ml of cold blood cardioplegic (1,120 ml of crystalloid-K⁺=100 meq/L) solution was infused. Because of the inability to obtain electrical silence of the myocardium with cardioplegia, myocardial protection was obtained by total body hypothermia. The resultant serum potassium was 7.4 meq/L at a blood temperature of 16°C. Because of the possibility of even higher serum potassium levels with rewarming, the hemoconcentrator was used to remove potassium with the ultrafiltrate. Volume was replaced with normal saline and packed red cells. Post-bypass, a cell saver was used to decrease the total volume returned to the patient, while further raising the hemoglobin concentration. The rationale for using the hemoconcentrator, and the potential consequences of untreated hyperkalemia accompanying severe hypothermia are discussed.