Statistical analysis
Power calculations were performed based on the primary endpoints. According to our preliminary study that included 24 patients, the incidence of clinical signs of awakening was 25% in the shallow anesthesia group (BIS 45 − 55) and 0% in the deep anesthesia group (BIS 25 − 35). With a two-tailed significance level of 0.05 and a power of 80%, 62 patients were required. Considering a dropout rate of 5%, 66 patients were in the study.Categorical variables were presented as numbers and percentages (%). Continuous variables were presented as mean ± standard deviation (SD), when the data were normally distributed, or as median (interquartile range, IQR) when the distribution was skewed. Normality was tested using the Shapiro–Wilk test. Categorical variables (clinical signs of awakening and MOAA/S scale score) were analyzed using the chi-square or Fisher’s exact test. We compared the change in BIS values from T