An ultrasound assessment of gastric emptying following tea with milk in pregnancy

BACKGROUND: Peri-operative fasting guidelines allow clear fluids including tea without milk to be consumed up to 2 h before surgery. Recent evidence has shown that a modest amount of milk consumed with clear fluids does not significantly slow gastric emptying. OBJECTIVES: The aim of this study was to compare the gastric emptying of tea with milk versus water using ultrasonography in fasted pregnant patients. DESIGN: A randomised controlled trial quantifying gastric emptying in two groups using ultrasonography by an operator blinded to the group allocation. SETTING: Department of Anaesthesia and Peri-operative Medicine, Coombe Women and Infants University Hospital, Dublin. The study was conducted between October 2018 and June 2019. PARTICIPANTS: Total 50 nonlabouring pregnant women, more than 36 weeks gestation. INTERVENTIONS: After a standard overnight fast, women were randomised to either 250 ml of water or 250 ml of tea with milk. All patients underwent a gastric ultrasound assessment at regular intervals for 2 h after consumption of their drink. MAIN OUTCOME MEASURE: The primary outcome was the difference in gastric antrum cross-sectional area (CSA) at 2 h. RESULTS: A total of 50 women were recruited to the study. There was no significant difference in the median IQR gastric antrum CSA in either group at 2 h: 3.2 cm 2.3 to 3.7 vs. 3.1 cm 2.6 to 3.9; P = 0.720. The gastric antrum CSA had returned to its baseline measurement in both groups by 90 min. CONCLUSION: The change of gastric antrum CSA after 250 ml of tea with milk is similar to a corresponding volume of water in fasted pregnant patients. This study could help inform future peri-operative fasting guidelines regarding the use of a modest volume of milk with clear fluids. TRIAL REGISTRY NUMBER: NCT03694509 ClinicalTrials.gov.