Evaluation of the effects of phosphorylcholine coated membrane oxygenators on renal functions in cardiac surgery patients

Objectives: Acute and chronic renal injury has an important effect on the surgical outcome of cardiovascular diseases in terms of morbidity and mortality. The coating techniques which have been significantly improved in the recent years aim to decrease the contact of blood with foreign surfaces in the cardiopulmonary bypass. The aim of this study is to research the effects of phosphorylcholine coating in the membrane oxygenators of cardiopulmonary bypass on renal functions in patients undergoing cardiac surgery. Materials and Methods: Thirty patients undergoing cardiac surgery were included to the study. Phosphorylcholine coated membrane oxygenator was used in one group (group 1) (n=15) and membrane oxygenator without coating with phosphorylcholine (group 2) (n=15) was used in the other group of patients. Preoperative and postoperative blood and urine analysis were obtained and data between the two groups were compared in order to evaluate the alterations in renal function. Results: Although plasma sodium and potassium as well as urine creatinine and microalbumin levels showed statistically significant difference within the groups, these values were not statistically different between the study groups. In both groups, creatinine clearance levels did not differ significantly. When the data within the groups are evaluated, creatinine clearance had a decrease in the early postoperative period whereas it increased over the preoperative levels in the third day after the operation. This situation did not show any statistical significance in the group 2 but the group 1. In our study groups, urine microalbumin analysis showed an increase in the early postoperative period, but then a steep decline was observed in the postoperative third day, which still has a value more than the preoperative one. Conclusions: Postoperative renal dysfunction is a multi-factorial entity with a wide spectrum of clinical presentations. The applied cardiac surgical procedure has a definitive role on the fate of renal failure. Although blood urea nitrogen and serum creatinine levels did not show statistically different variation, creatinine clearance was even increased in the study group.