Statistical analysis
All statistical analyses were calculated by SPSS 22.0 (Statistical Packages for the Social Sciences, SPPS Inc., Chicago, IL, USA). The normal distribution was determined by Kolmogorov Smirnov test and histogram. All of the parameters were not normally distributed probably because of the low group sizes. Non-parametric tests are used for calculations. The continuous variables were expressed as median (min-max). The categorical variables were expressed as n (%). The differences of continuous variables were calculated by the Mann Whitney-U test and the Wilcoxon signed rank test was used for repeated measures. Chi-Square test was used to determine the difference between groups of categorical variables. p<0.05 were considered as statistically significant. The sample size was determined using the preliminary data of 10 patients. In power analysis, a minimum of 48 patients were shown for β = 0.1 and α = 0.05.
Results After obtaining the ethics committee approval, 74 patients were included in the study. Out of 74 patients, 60 patients were included in this study, after exclusion of 14 patients according to the exclusion criteria (Figure 1). Thirty patients with BMI <30 were classified as Group 1, the remaining 30 patients with BMI ≥ 30 were classified as Group 2. The mean age of the patients was 38,22±10,35 and 61,6% of the patients were women. There was no statistically significant difference between the groups in terms of chronic diseases, operation duration and pneumoperitoneum duration. Demographic data of the patients are shown in Table 1. Data on systolic blood pressure, diastolic blood pressure and heart rates are shown in Figures 2 and 3. From these data, only the systolic blood pressure baseline value was significantly higher in Group 2 (p = 0.007), but there was no significant difference between the groups in other time frames and other measurements. The comparison of hemodynamic monitoring parameters between T0 and T5 is shown in Table 2. Statistically no significant difference was found between the groups at all measurement times for PVI and SpHb values. Figure 4 and Figure 5 show the changes of PVI and SpHb over time. Measurements over all time periods were compared with T0 and T5 separately. In comparison of PVI measurement values ​​with T0, a statistically significant difference was found in T3, T4 and T5 in Group 2 (p = 0.010; 0.012; 0.041, respectively). In comparison with T5, statistically no significant difference was found in both groups. In comparison of SpHb measurement values ​​with T0, a statistically significant difference was found in T1, T2 and T3 in Group 2 (p = 0.008; 0.010; 0.037, respectively). In comparison with T5, there was a statistically significant difference in T1, T2 and T3 in Group 2 (p = 0.023; 0.005; 0.006, respectively).