Statistical analysis
blood loss, pruritus, pain
BLOOD LOSS, DISEASE
Variables were summarized as mean ± SD for normally distributed continuous variables (including demographic profile of the patients, duration of surgery, fluid intake and output, hemodynamic changes, Intra-operative remifentanil use, propofol use, first feeding time, first time out of bed, QoR-15 score), and intergroup comparisons were performed using one-way analysis of variance (ANOVA). Median (25th to 75th percentile) for continuous variables with evidence of nonnormality or for ordinal variables (Hospital stay days, blood loss, pain scores, cumulative amount of IVPCA sufentanil used, time of first analgesic request, post-operative extubation time), comparisons between groups were made using the Kruskal–Wallis test. Frequency counts and percentages for categorical variables were analysed using the Pearson’s chi-squared test (sex, ASA physical status, underlying disease, chest drain days, nausea/vomiting) or Fisher’s exact test (pruritus). Statistical analysis was performed using statistical software SPSS (25.0; IBM Corp., Armonk, NY, USA). The 95% confidence intervals of the median differences were estimated by bootstrap method based on resampling through Python version 2.7.6. The significance level was set at 