METABOLIC CONTROL OF NON-INSULIN-DEPENDENT DIABETIC-PATIENTS UNDERGOING CATARACT-SURGERY - COMPARISON OFLOCAL AND GENERAL-ANESTHESIA

We studied 40 elderly patients undergoing cataract surgery. Ten non-in sulin-dependent diabetes mellitus (NIDDM) patients received standardiz ed general anaesthesia, 10 NIDDM patients received local anaesthesia u sing retrobulbar block, 10 nondiabetic control patients received gener al anaesthesia and 10 non-diabetic controls received retrobulbar block . We measured sequential changes in blood glucose, lactate and beta-hy droxybutyrate, serum cortisol and insulin, and plasma non-esterified f atty acid concentrations until 4 h after operation. The results showed that in both general anaesthesia groups, NIDDM and control, blood glu cose and serum cortisol concentrations increased significantly during surgery, before returning to normal by 4 h after operation; in both lo cal anaesthesia groups, glucose and cortisol concentrations changed li ttle during surgery. Serum insulin concentrations increased 30 min aft er operation to coincide with the peak of the glucose increase in the non-diabetic patients who received general anaesthesia, but no insulin response was seen in the diabetic general anaesthesia patients. Blood glucose and insulin concentrations increased in patients who received local anaesthesia (NIDDM and controls) when they ate after operation. The results show that cataract surgery under local anaesthesia provid es improved metabolic control for the diabetic patient. Its use mainta ins glucose homeostasis, prevents the increases in cortisol and glucos e which are seen under general anaesthesia and obviates the need for p ostoperative starvation.