Complications but not obesity or diabetes mellitus have impact on the intraperitoneal lactate/pyruvate ratio measured by microdialysis

Objective. Studies have shown a higher risk of postoperative complications in diabetic and obese patients. An increased intraperitoneal lactate/pyruvate ratio as measured by microdialysis has been reported before postoperative complications have been discovered. It is not known whether diabetes or obesity have any influence on the intraperitoneal metabolism (lactate/pyruvate ratio, glucose, glycerol) in relation to major abdominal surgery. The aim of this study was to investigate the postoperative intraperitoneal and subcutaneous carbohydrate and fat metabolism as measured by microdialysis in obese and diabetic patients after major abdominal surgery without postoperative complications. Material and methods. Seven obese patients (body mass index > 30 kg/m(2)) and six diabetic but non-obese patients were studied up to 48 h after major abdominal surgery and were compared with 31 non-diabetic, non-obese patients, all without complications. Microdialysis was performed to measure glucose, lactate, pyruvate and glycerol intraperitoneally and subcutaneously. The lactate/pyruvate ratio was calculated. Results. The lactate/pyruvate ratio did not differ between the groups. In the diabetic patients, glucose levels were higher intraperitoneally at both Days 1 and 2 compared to controls. Higher glycerol levels were found subcutaneously in obese patients at Day 2. Conclusions. The lactate/pyruvate ratio does not increase intraperitoneally after non-complicated major abdominal surgery in diabetic and obese patients. Obese patients have increased release of free fatty acids and glycerol subcutaneously, while diabetic patients show higher glucose levels intraperitoneally than controls.