Statistical analysis
The sample size was calculated using MedCalc Software version 14 (MedCalc Software bvba, Ostend, Belgium) to find the null hypothesis with the area under the receiver operating characteristic (AUROC) curve of 0.5 and AUROC of 0.80. We calculated a minimum of 45 patients for a study power of 80% and an error of 0.05 because it is assumed that the success rate of the infraclavicular block is more than 80%.The data collected in the study were analyzed using the SPSS 22.0 (Statistical Package for the Social Sciences) program. The normality of the distributions of the variables was tested using visual (histograms and probability plots) and analytical (Shapiro–Wilk test) methods. Levene’s test was used to check the homogeneity of the group variances. The mean differences between two groups were analyzed with Student’s t test. In the intragroup comparisons of time-related changes, the Friedman test was used for the non-normally distributed variables. For the post hoc comparisons, Wilcoxon signed-rank test was applied separately for pair of groups. Each output was reported by applying Bonferroni correction. The receiver operating characteristic (ROC) curve was used to examine the recorded values for our outcome criteria in terms of their diagnostic value. The Hanley and McNeil method was used to calculate the ROC curve and the area under the ROC curve (AUC). AUC values close to 1.0 were interpreted as indicating an improvement in prediction accuracy. The type 1 error rate of 5% was accepted for significance in all statistical analyses.