Statistical Analysis
The primary outcome of the study was total propofol consumption. The power analysis was based on the results of the study conducted by Luginbuhl et al. [12]. The authors found that total consumption of propofol was 6.03±1.4 mg/kg and 6.64±0.9 mg/kg consecutively in groups using BIS and not using BIS (p=0.023). With a power of 80% and an alpha error of 5%, the sample size calculation determined that 60 patients were required for each group, using the G ∗ Power (v3.1.7) program. Considering the possibility of drop out and lack of data, the total number of patients required for the study was determined to be 130 (65 patients for each group). We analyzed the data with SPSS version 16 (SPSS Inc., Chicago, Illinois, USA). Convenience of parameters to the normal distribution was assessed with Shapiro Wilks test while assessing the study data. Student t-test was used in comparing quantitative data for comparing parameters that showed normal distribution between the two groups, while Mann-Whitney U test was used in comparing data that did not show a normal distribution between the two groups. Chi-square test and Fisher’s exact tests were used in comparing qualitative parameters. p ≤ 0.005 was considered statistically significant.