Pre-anaesthetic sonographic assessment of gastric antrum in parturient scheduled for elective caesarean section – A prospective cross-sectional study

Abstract

Background and Aims: Point-of-care ultrasonography (USG) of the gastric antrum can help to evaluate the aspiration risk and improve the safety of anaesthesia. The aim was to assess the gastric antrum in term parturients scheduled for elective caesarean section using bedside USG. Methods: After obtaining institutional ethics committee approval and written informed consent, 250 term parturients (≥36 weeks gestational age) with body mass index 18.5–30 kg/m2, and scheduled for elective caesarean delivery were included in this study. The parturients were instructed to follow standard fasting guidelines. In the preoperative area, ultrasonographic examinations were performed 15 min before the scheduled time of the caesarean section. The primary outcome was the qualitative assessment (grade 0–2) of the gastric antrum, and the secondary outcome was the quantitative assessment (antral cross-sectional area [CSA]) of gastric antrum in supine and right lateral decubitus (RLD) position. Data analysis was done using Statistical Package for Social Sciences Software (version 19). Results: Among the 234 parturients who completed the study, 191 exhibited grade 0 antrum, 42 had grade 1 antrum, and one parturient had grade 2 antrum. Overall, 83% of participants had an antral CSA ≤4.25 cm2 [95% confidence interval (CI), 2.52–5.67 cm2] in the RLD position, equivalent to an estimated gastric volume of ≤43 ml (95% CI, 32–68 mL) or ≤1.5 ml/kg (95% CI, 0.49–1.23 ml/kg). Conclusion: Majority of fasted term parturients scheduled for elective caesarean section had a grade 1 gastric antrum on bedside USG. This study also establishes cutoff values of antral CSA and gastric volume in both supine and RLD position for fasted term parturients.

Keywords

• pregnancy
• pyloric antrum
• ultrasonography