Effects of a Preoperative Carbohydrate-Rich Drink Before Ambulatory Surgery: A Randomized Controlled, Double-Blinded Study

BACKGROUND The guidelines recommend oral carbohydrates up to 2 hr before elective surgery. The objective of this study was to explore the safety and feasibility of preoperative carbohydrate drink in patients undergoing ambulatory surgery. MATERIAL AND METHODS Patients undergoing ambulatory surgery under general anesthesia were enrolled. They were fasted from midnight and randomly assigned to a study group (200 mL of a carbohydrate beverage) or the control group (pure water) and received the assigned drink 2 hr before surgery. Bedside ultrasonography was performed to monitor gastric emptying at T₀ (before liquid intake), T₁ (5 min after intake), T₂ (1 hr after intake), and T₃ (2 hr after intake). Subjective feelings of thirst, hunger, anxiety, and fatigue were assessed 1 hr after liquid intake using the visual analogue scale (VAS). RESULTS In both groups, gastric antrum cross-sectional area, gastric content volume, and weight-corrected gastric content volume increased at T₁ and returned to baseline at T₃. These parameters were significantly higher in the study group at T₂ (6.28±1.38 vs. 4.98±0.78, 67.22±29.49 vs. 49.04±15.4, 1.10±0.51 vs. 0.85±0.37, P<0.05). Thirst and hunger VAS scores were reduced in both groups. The study group suffered significantly less hunger (28.44±10.41 vs. 36.03±14.42, P<0.05). Blood electrolytes (sodium, potassium, calcium) and glucose concentration levels were similar in both groups at T₂. No gastric regurgitation or pulmonary aspiration was recorded. CONCLUSIONS Administration of 200 mL of oral carbohydrate beverage 2 hr before ambulatory surgery is safe, effective, and can be used for preoperative management of fasting patients.