Effects of open-heart surgery on carbohydrate and lipid metabolism

The concentrations of blood glucose, serum insulin, free fatty acids, and triglycerides were examined preoperatively, during anesthesia, during extracorporeal circulation, and during the following 3 postoperative days in 29 patients. The patients were divided into three groups according to the duration of extracorporeal circulation and the use of hypothermia: short perfusion group (SPG, bypass time shorter than 60 minutes, 15 patients), long perfusion group in normothermia (LPGN, bypass time longer than 60 minutes, 8 patients), and long perfusion group in hypothermia (LPGH, temperature during bypass below 33 degrees C., 6 patients). In all three groups, the concentrations of free fatty acids and blood glucose rose significantly because of anesthesia (p less than 0.001). After cardiopulmonary bypass, the concentrations of free fatty acids diminished significantly. The blood glucose remained at high level until the second postoperative day and was significantly higher in the LPG than in the SPG (p less than 0.05). The serum insulin level remained low during anesthesia and extracorporeal circulation in the SPG and LPGH but rose during the postoperative period; the maximal values were recorded on the first postoperative day. There were no significant differences between the groups with regard to serum insulin during the study. These changes and their metabolic background are discussed.