A new sterile bicarbonate dialysis solution for use during cardiopulmonary bypass

Adding a dialysis filter to the perfusion circuit at the end of cardiopulmonary bypass (CPB) has become an accepted means of reducing potassium rapidly and safely. Rapid removal of solute requires a dialysate for diffusion, and peritoneal dialysis solutions have been the standard because of availability, although occasionally normal saline or bicarb/ saline mixtures are used. Cardioplegia solution is high in glucose as well as potassium and, with many diabetic patients undergoing CPB, it is desirable to minimize glucose loads. In this prospective cohort study, six patients received a commercially available sterile bicarbonate dialysate prepared in a point of care fashion. From the cardiovascular data base, four control patients (receiving lactate based dialysis solution during CPB) were matched for age, surgery type, body surface area (BSA), and pump duration for each of the six patients receiving bicarbonate dialysate. All of the control patients were dialysed against lactate buffered peritoneal dialysis solution. Plasma levels of potassium, glucose, and bicarb were measured before and after dialysis for each dialysate. Plasma potassium, glucose, and bicarb were not significantly different at start of dialysis. The lactate dialysate (LD) group received a mean of 17.4+/-7.7 L of lactate containing dialysate versus 14.6+/-4.7 L of bicarbonate dialysate (BD) (p = 0.41). After dialysis, potassium had been reduced to a similar degree in both groups, but plasma glucose levels had increased during LD while they fell during BD, and bicarbonate levels fell during LD while they rose during BD. Use of a commercially available sterile bicarbonate dialysate can safely help to lower plasma potassium during CPB and preserve more physiologic levels of glucose and bicarbonate.