Diabetes Mellitus

management of the diabetic patient before, during, and after surgery is an important responsibility of the surgeon. hyperglycemia should be avoided during surgery. the greater danger is from severe unrecognized hypoglycemia.
-preoperative
physical trauma combined with physiologic stress may cause epinephrine and cortisol level to rise, in each case resulting in increased blood glucose levels. hypocalemia may prevent B cell from secreting adequate amounts of insulin and may thereby raise blood glucose levels in patients with type 2 diabetes. an ecg to rule out myocardial infarction, a chest x ray to identify hidden pneumonia or pulmonary edema, urinalysis can rule out urinary tract infection and proteinuria, serum creatinine levels are used to asses renal function. the serum glucose concentration should ideally be between 100 and 200mg/dL, but operation can be safely performed in patients whose serum glucose is as high as 350-400mg/dL preoperatively.
a. type 2 Diabetes mellitus
if the serum glucose level is below 250mg/dL on the morning of surgery, sulfonylureas should be withheld. long acting sulfonylureas should be discontinued on the day before surgery and 5% glucose solution should be administered iv at a rate of about 100mL/h. this means that over a 10-hour period, only 50g of glucose would be given.
if the fasting glucose level is above 250-300mg/dL or if the patient is taking small doses of insulin but does not actually require insulin to prevent ketoacidosis, an alternative approach is to add 5 units of insulin directly to each liter 0f 5% glucose solution being given at 100mL/h. if the operation is lengthy, blood glucose levels should be measured every 3-4 h during surgery to ensure adequate glucose control. the goal is to maintain glucose levels between 100 and 200mg/dL, but there is little immediate metabolic harm in allowing levels to go as high as 250mg/dL.
b. type 1 Diabetes mellitus
patients require insulin during surgery. the following methode: 1. subcutaneous administration of long -acting insulin. 2. constant infusion of a mixture of glucose and insulin. 3. separate infusion of glucose and insulin. blood glucose levels should be monitored at least every 2 hours during the procedure to avoid hypoglycemia below 60mg/dL and hyperglycemia above 250mg/dL.

- postoperative
an infusion of 1.5 units or less of insulin per hour, when given with 5% glucose, rarely results in hypoglycemia. blood glucose levels should be measured every 2-4 hours and the patient monitored for signs and symptoms of hypoglycemia ( anxiety, tremulousness, profuse sweating without fever ). a marked increase in glucose and insulin requirements postoperatively suggest the presence of occult infection.