Background: Surgery causes a considerable metabolic stress in both diabetic and nondiabetic patient, but the   severity of stress induced hyperglycemia is considerably high in diabetic  patient  . In
non-diabetic subjects the stress response is more in obese population than in non-obese due to the presence of insulin resistance. The
severity of surgery as well as the type of anesthesia influence the magnitude of the stress response The study was undertaken to observe the effect of stress   in obese and non-obese non-diabetic patients
undergoing craniotomy under general anesthesia.

Methods: A Prospective randomized parallel group study was done on a total of 100 patients. They were divided into two groups non-obese
patients and obese patients comprising of 50 patients in each group depending on their BMI. If at any time intraoperative CBG was found to
be more than or equal to 150 mg/dL calculated  dose of human soluble insulin was given as intravenous bolus equal to the amount of CBG/100
units. Number of hyperglycaemic episode and total insulin consumption
in both group were the primary outcome of study.

Results: 36% patients in obese population developed at least one
episode of hyperglycemia (CBG ≥ 150 mg/dL) whereas only 20% patients
in non-obese population had hyperglycemia episode .   The relative
risk of  hyperglycemic in obese was higher than non-obese [ 1.80 (95%
CI 0.92 to 3.51)]. The total intraoperative  and postoperative
insulin requirement were significantly higher  in non-obese population
 than obese  and the difference was statistically significant (p=0.02)
Conclusions: We conclude that stress induced hyperglycemic response in
patients undergoing craniotomy surgery under general anaesthesia is
common in both   diabetic and non-diabetic population  and the
relative risk  is more in  obese patients than non-obese.