A Prospective, double-blinded randomized controlled study comparing two different Trendelenburg tilts in laparoscopically assisted vaginal hysterectomy positioning

Abstract

Background: Bispectral index (BIS) used for intra-operative depth assessment under general anesthesia (GA) can be altered by different factors. This study was designed to detect the alteration in BIS reading with two different Trendelenburg (TBG) tilt in laparoscopically assisted vaginal hysterectomy (LAVH) procedure.

Materials and methods: A prospective, double-blinded, randomized controlled study was designed involving 40 American Society of Anesthesiologists Grade I and II female patients, aged 35-60 years, scheduled to undergo LAVH under GA. Patients were divided into two groups with TBG >30° and TBG <30°. BIS readings; systolic and diastolic blood pressure, heart rate were recorded in supine position. Patients were then shifted to desired TBG position either (>30°) or (<30°) as per group allotment. Data were recorded at 30 min intervals and all the patients were followed upto 24 h postoperatively for any recall.

Results: A rise in BIS value was noticed, when position was changed from supine to head down in both groups. During comparison between two groups with different angulations, TBG >30° showed a higher BIS value than TBG <30°. This statistically significant (P < 0.05) trend was observed at all the 30, 60, 90, and 120(th) min interval. Interestingly, BIS values returned to preoperative levels following adopting final supine position. No incidence of awareness was reported in both the series throughout the study.

Conclusion: Though awareness remains unaltered BIS value gets increased with higher angle of inclination in TBG position during LAVH operation.

Keywords: Bispectral index; Trendelenburg; general anesthesia; laparoscopically assisted vaginal hysterectomy; post anesthesia care unit.

Figure 1

Comparison of bispectral index value in two different Trendelenburg position