Corrigendum to “Effect of metoclopramide on gastric volume and nausea and vomiting outcomes in fasted patients undergoing Elective Cesarean delivery: a randomized clinical equivalence trial”. [Int. J. Obstetr. Anesth. 64 (2025) 104754] (International Journal of Obstetric Anesthesia (2025) 64, (S0959289X25003462), (10.1016/j.ijoa.2025.104754))

The authors regret that the sample size assumptions presented in the methods section of the article were not the original assumptions made at the time of the study registration in August 2021. The initial sample size calculation submitted to ClinicalTrials.gov (NCT05033041) was based on the study by Arzola et al. (2015), which measured gastric volumes in fasted pregnant women.¹ The study reported a median gastric volume of 48.1 mL and an interquartile range of 45 mL. Based on this data, we estimated a reference mean of 50 mL and a standard deviation of 25 mL. Using an equivalence test of means with two one-sided tests (TOST) for a parallel-group design, a sample size of 36 participants per group was determined to achieve 81 % power at a 5 % one-sided significance level. This calculation assumed a treatment mean of 40 mL, a reference mean of 50 mL, and equivalence limits of ± 25 mL. Subsequently, we refined our assumptions using data from a study by Hamed et al. (2023), which measured changes in gastric volume before and after metoclopramide administration in pregnant women.² Their observed change in gastric volume following intravenous metoclopramide 10 mg administration was −34 %. Based on this finding, we revised our estimated clinically important difference from −50 % to −34 % following metoclopramide administration. Applying this refined difference in an equivalence test of means using TOST, a sample size of 34 participants per group (metoclopramide vs. saline) provides 80 % power to detect equivalence at a one-sided alpha level of 0.025. This calculation assumes a treatment mean of 33 mL, a reference group mean of 50 mL, a standard deviation of 25 mL, and an equivalence margin of ± 17 mL. The authors would like to apologise for any inconvenience caused by this error.