Comparison of Gastric Volume, Gastric pH, and Metabolic Parameters Following Overnight Fasting Versus Clear Fluid Intake Two Hours Before Laparoscopic Abdominal Surgeries: A Prospective Randomized Clinical Study

Background: Aspiration of the gastric contents in the perioperative period is a serious complication of surgery and anaesthesia. Pre-operative fasting aims to reduce gastric volume and increases pH, thereby decreasing the risk of aspiration. This study compared gastric volume measured by ultrasonography, gastric pH, serum glucose, serum electrolytes, and serum lactate (metabolic parameters) in patients after overnight fasting versus after ingestion of 200 ml of clear fluid (water) 2 hours before laparoscopic abdominal surgery. Material and Methods: It was a prospective, randomised clinical study conducted at a hospital, in which patients aged ≥18 years undergoing elective surgery under general anaesthesia served as subjects. The subjects were randomised into two groups based on a computer-generated randomisation table: Group A (overnight fasting) and Group B (200 ml of clear water 2 hours before surgery). Gastric volume was evaluated with the help of ultrasonography, and the pH of gastric contents was measured with the help of pH strips after aspirating. Serum glucose, electrolytes, and lactate were examined. Results: Our research revealed no significant differences between groups in age, sex, or weight. Ultrasonic measurement of the mean gastric volume was much smaller in Group B (20.2 ± 4.3 ml) than in Group A (28.9 ± 7.9 ml; p < 0.001). There was a statistically higher difference between Mean gastric pH in Group B (2.57 ± 0.89) and Group A (1.39 ± 0.7; p < 0.001). There was also much less difference in serum potassium and serum lactate levels in group B. Conclusion: We concluded that allowing clear fluids during the preoperative period was associated with reduced gastric volume, higher gastric pH and improved metabolic parameters, without evidence of increased aspiration risk. Implementation of evidence-based fasting guidelines may help reduce patient discomfort, dehydration and metabolic stress associated with prolonged fasting.

Keywords: Ultrasonography, Gastric volume, Gastric pH, random blood sugar, Serum electrolytes.