The Effect of BIS Usage on Anaesthetic Agent Consumption, Haemodynamics and Recovery Time in Supratentorial Mass Surgery

Abstract

Objective: In this study, we aimed to compare Bispectral Index (BIS) monitoring with the conventional anaesthesia approach based on haemodynamic changes in terms of anaesthetic agent consumption, haemodynamic recordings, recovery time and cost.

Methods: This study was performed in 82 patients, aged 20 to 60 years, who were operated for supratentorial mass and were graded ASA I or II. Cases were randomly divided into two equal groups. In the standard control group haemodynamic parameters were used to determine depth of anaesthesia and in the BIS group, BIS monitoring was applied. In the BIS group the BIS values were kept between 40 and 60; in the control group haemodynamic changes within the range of +/-20% of initial values were controlled using appropriate anaesthetic practice. Haemodynamic parameters, awakening conditions and drug usage were recorded.

Results: The difference between the two groups in terms of timing of eye opening and initial spontaneous breath was not statistically significant. The 'Aldrete' score at the 20(th) postoperative minute for the BIS group was significantly higher than the score calculated for the control group (p<0.05). Rocuronium consumption (mg kg(-1) hr(-1)) was significantly lower in the BIS group than the control group (p<0.05). Although a statistically significant difference (p<0.05) was found between the two groups in terms of initial heart rate and SpO2 values, there was no clinically significant difference in other haemodynamic parameters.

Conclusion: Although using BIS monitoring to evaluate depth of anaesthesia does not bring much benefit versus the use of haemodynamic parameters, it may be beneficial for selected surgeries such as awake craniotomy, for patients with a history of awareness and in haemodynamically unstable patients.

Keywords: BIS monitoring; depth of anaesthesia; haemodynamics; neurosurgery.

Figure 1

The change in BIS values according to time in the BIS group 1: Before induction, 2: Induction, 3: After intubation, 4: At the beginning of surgery, 5: Brain manuplation, 6: Bleeding control, 7: Skin closure, 8: After extubation