Statistical analysis
nausea and vomiting, acute pain, nausea and/or vomiting
According to our routine observations, the incidence of nausea and vomiting in ED patients with acute pain treated with intravenous tramadol was approximately 30%. We assumed that administration of intravenous metoclopramide would result in a reduction of nausea and vomiting incidence by 25 percentage points compared to placebo. To achieve statistical power of 80% at 5% one-sided significance level, with an anticipated 10% drop-out rate, a total of 64 patients was required.Categorical data were described with frequency and percentage. Mean and standard deviation (SD) for Normally-distributed numerical data, and median and interquartile range (IQR) for non-Normally distributed numerical data. The normality of data was justified based on histogram and Shapiro–Wilk test. The incidence of nausea and/or vomiting between the two treatment arms were compared using Fisher’s exact probability test (one-sided). The analysis was performed using the intention-to-treat principle where all patients were included in the analysis and were analyzed according to which group they were initially assigned. P values less than 0.05 were considered statistically significant differences. All statistical analyses were conducted using Stata 17 (StataCorp, College Station, TX, USA).