LAUSR

BACKGROUND AND OBJECTIVES Pregnant women are considered patients at risk for pulmonary aspiration of gastric contents. The study aim was to evaluate the gastric antral cross-sectional area using ultrasound. METHOD In this prospective study, 85 scheduled term pregnant women underwent gastric ultrasound. The outcomes were the measurement of the gastric antral cross-sectional area (main outcome), the estimated gastric volume, the incidence of pregnant women at risk for pulmonary aspiration, and the association between gastric antral cross-sectional area and clinical-demographic characteristics. Gastric antral cross-sectional area and gastric volume were compared according to body mass index <30 or ≥ 30. RESULTS The median (IIQ) for gastric antral cross-sectional area was 4cm2 (2.8-6.3), for the estimated gastric volume it was 49.8mL (33.7-87.2), and for the gastric volume estimated in mL.kg-1 it was 0.62mL.kg-1 (0.39-0.95). The 95th percentile [95% confidence interval (CI)] of the gastric antral cross-sectional area and the estimated gastric volume were ≤ 10.3cm2 (95% CI: 7.6-15.6) and 1.42mL.kg-1 (95% CI: 1.20-2.64), respectively. The incidence of pregnant women at risk for pulmonary aspiration was 3.5% (CI: 3.5 (1.2-9.8). There was a positive correlation between gastric antral cross-sectional area and weight, p <0.001 and body mass index <0.001. Patients with a body mass index ≥ 30 had a gastric antral cross-sectional area and an estimated gastric volume greater than those with a body mass index <30, respectively, p <0.01 and p <0.02. CONCLUSION Measuring the gastric antral cross-sectional area of pregnant women is feasible and easy. There was positive correlation between gastric antral cross-sectional area, body weight and body mass index. The estimation of gastric volume by measuring the gastric antral cross-sectional area can identify patients at risk for pulmonary aspiration. Obese patients had a gastric antral cross-sectional area and an estimated gastric volume greater than non-obese patients.