Pre-operative Carbohydrate Loading Patients With Diabetes Undergoing Elective Colorectal Surgery

Fasting prior to the administration of a general anesthetic has been the standard of peri-operative care for many years. The refrain of "nothing to eat or drink after midnight" has become synonymous with surgery for both clinicians and the general public. The rationale behind this practice has been to reduce the risk of regurgitation of gastric contents. In addition, this instruction is straightforward for patients and ancillary staff, and allows for easy alteration of the order of cases on the operative list. Despite the widespread nature of this practice, a 2003 Cochrane review attempted to define the optimum duration of fasting, type of fasting, and volume of intake permitted and concluded that there was no evidence to suggest a shortened fluid fast resulted in an increased risk of aspiration, regurgitation, or morbidity in healthy patients.

Pre-operative fasting leads to insulin resistance and metabolic stresses. More recently it has been suggested that a preoperative carbohydrate loading may alleviate some deleterious effects of this fast. This strategy, combined with a number of others, have been recently introduced in many Enhanced Recovery After Surgery (ERAS) programs, that have led to improved postoperative pain, faster restoration of GI function, decreased LOS and decreased complication rate after colon surgery.

Type 2 diabetes is a disease of impaired glucose tolerance. It is a common condition that affects over 15% of general surgical patients undergoing major abdominal surgery. It is well recognized that this is a high-risk surgical population that is at increased risk of perioperative complications such as anastomotic dehiscence, poor wound healing, and postoperative ileus which can lead to an increased LOS after surgery. However, there is a relative dearth of robust evidence regarding preoperative fasting in patients with type 2 diabetes so there is no consensus among professional association guidelines internationally on recommendations for carbohydrate loading in this population undergoing elective surgery. Two major concerns have been raised; first the risk of aspiration in diabetic patients with a significant neuropathy and gastroparesis, and second potential for hyperglycemia and its deleterious effects.