Ultrasound your NPO: Effect of body mass index on gastric volume in term pregnant women – Retrospective case series

INTRODUCTION: A common belief has been that obese patients are prone to develop aspiration of gastric contents when general anesthesia is administered. We aimed to determine the correlation between antral cross-sectional area as a surrogate of gastric volume measured by gastric ultrasound, and body mass index (BMI) in term pregnant women scheduled for elective cesarean section. METHODS: A cross-sectional observational study was conducted on forty-two term pregnant patients scheduled for cesarean section. A preoperative qualitative and quantitative ultrasound assessment of the antral area was performed on the day of surgery. Gastric volume as a function of BMI was evaluated. RESULTS: A significant correlation was found between BMI and gastric antral area (p = 0.001), as well as with longitudinal diameter (p < 0.001). This correlation is independent of gravidity and parity. CONCLUSION: BMI is an independent predictor of the antral cross-sectional area and gastric volume in term pregnant patients scheduled for cesarean section. Perioperative fasting guidelines in pregnancy should be adjusted in obese and morbidly obese pregnant women.