Abstract No. : ABS2942: Comparison of ultrasonographic gastric content and volume in patients posted for elective surgery with preoperative fasting for different durations

BACKGROUND&AIMS: Nilbymouthrules reduces the risk of aspiration. But prolonged fasting lead to patient discomfort and haemodynamic changes during anaesthesia. The aim of our study was to investigate if prolonged fasting for water is an absolute necessity in healthy young adults undergoing elective surgery. METHODS: 290 adult patients, between 18-50 years of age, non-obese, undergoing elective surgeries, were assigned by simple randomisation into 2 groups, patients for 8 hours of fasting and patients who can have water upto 500 ml until 2 hours prior to surgery. A preoperative gastric ultrasound was done in right lateral position before the surgery. Residual gastric contents and volume were estimated by measuring antral cross-sectional area(ACSA) using the following mathematical formulas; ACSA = ((anteroposterior diameter × craniocaudal diameter ×3.14))/4 Gastric volume = 27+(14.6×ACSA) - [1.28×Age] Gastric volume upto 1.5 ml/kg is considered safe during induction of anesthesia. RESULTS: It was found that there was an increased mean gastric volume in patients with fasting more than 8 hours when compared with patients who were allowed to have water up to 2 hours prior to the surgery. There was a positive correlation between number of fasting hours and gastric volume. Though it is statistically significant, it is far below the permissible gastric volume per kg body weight (<1.5 ml/kg). CONCLUSION: Allowing patients to have water until 2 hours of surgery is a safe practice when compared with prolonged fasting of >8 hours for water.