The Effects of Glasgow Coma Scales and Bispectral Index on General Anaesthesia in Neurosurgery Patients

Objective: Monitorisation under anaesthesia is important for objective evaluation in intracranial surgery. We investigated general anaesthesia management performed by bispectral index (BIS) monitoring in patients who underwent surgery due to intracranial pathology with different Glasgow Coma Scales (GCS). Methods: Forty-five patients who had been planned to undergo intracranial surgery under general anaesthesia were included in the study. Patients were divided into three groups according to GCS: Group I (n = 15) = 13-15 mildly injured; Group II (n = 15) = 9-12 moderately damaged; Group III (n = 15) = 3-8 severely damaged. Heart rate (HR), mean blood pressure, and use of anaesthetic agent were recorded. Results: It was found that the consumption of the inhalation agent in Group III was lower than Groups I and II at all time intervals measured, and it was lower in Group II than Group I during the intervals at intraoperative 15th minute and up to 150th minute thereafter. The inhalation agent consumption rates according to the duration of anaesthesia were different between groups. The HR was significantly higher in Group III compared with Group II during the post-operative period. The mean arterial pressure was significantly lower in Group I than Group II pre-operatively and at 5th, 10th, 15th, 20th, and 40th minute intra-operatively, whilst it was significantly lower in Group I than Group III preoperatively and 10th minute and 15th minute, intraoperatively. Conclusion: We found that in patients whose GCS was severely damaged and underwent intracranial surgery under general anaesthesia with BIS monitoring, the consumption of inhalation anaesthetic agent decreased, but opioid consumption did not change.