A randomised controlled study of preoperative oral carbohydrate loading versus fasting in patients undergoing colorectal surgery.

This study aimed to evaluate the effect of preoperative carbohydrate oral (CHO) loading on the postoperative metabolic and inflammatory response, perioperative discomfort and surgical clinical outcomes in open colorectal surgery compared with a conventional fasting protocol.

Fifty patients were randomly allocated to either the intervention group (CHO), to receive preoperative oral carbohydrate supplementation, or the control group (FAST), to undergo preoperative fasting. Insulin resistance, insulin sensitivity, the Glasgow Prognostic Score (GPS) and IL-6 levels were analysed at 06 h on the day of surgery (T₁), 6 h after surgery (T₂) and at 06 h on postoperative day 1 (T₃) and postoperative day 2 (T₄). Thirst, hunger, dry mouth, weakness, anxiety and pain were assessed using the visual analogue scale (VAS) prior to anaesthesia induction and at 0-4, 4-8, 8-12 and 12-24 h after surgery. Surgical clinical outcomes included the return of gastrointestinal function, time to independent ambulation and postoperative discharge day.

Postoperative insulin resistance was 30% lower (p < 0.03) and insulin sensitivity was 15% higher (p < 0.05) in the CHO group than in the FAST group. The GPS was lower in the CHO group at T₁ (p < 0.001), T₃ (p < 0.01) and T₄ (p < 0.004). IL-6 serum levels were lower at the analysed postoperative time points in the CHO group (p < 0.001). The VAS well-being score was lower in the intervention group (p < 0.001); however, the VAS pain score was not significantly different between the groups. The evaluated surgical outcomes appeared earlier in the CHO group (p < 0.001).

A preoperative CHO drink reduced the postoperative metabolic and inflammatory response and improved subjective well-being and surgical clinical outcomes but did not diminish the VAS pain score.