To evaluate the effect of intraoperative sedation dosage on awakening and recovery of consciousness after elective neurosurgical surgery.

The project will have a total duration of 24 months and will mainly consist of a data collection phase (months 1-24) and a data analysis and results publication phase (months 15-24). Preoperative clinical and socio-demographic data will be collected from patients' medical records. Psychological variables will be administered to the patient before elective neurosurgical surgery.

BIS-guided general anesthesia will be induced by administering sedative and analgesic drugs to the effector site Ce (Effect Site) by target-controlled infusion (TCI). Propofol and remifentanil will be titrated to maintain blood pressure, body temperature, pCO2 and SaO2 in a normal range and BIS values between 40 and 60. Pharmacological data will be relevant at the end of the intervention from the drug infusion pumps. The Recovery Room multidisciplinary team will assess the quality of awakening following the Awakening Chart (Figure 1). This assessment involves dichotomous scoring (yes/no; correct/incorrect) of specific items. To assess the recovery of consciousness, during the pre-extubation phase, simple requests/questions will be asked of the patient: show tongue; show two fingers; give phone number; state place; identify what day is today; report date of birth; notify residence; perform simple multiplication (e.g., 4x5). The following variables will be collected during the periestubation phase: cough, blood pressure ± 20% of baseline, chills, NRS > 3, RASS < -1 or > 0. An abbreviated version of the STAI questionnaire will also be administered to the patient to assess anxiety on awakening. Awakening is considered good and optimal only if a score of 13 is achieved.

Inclusion Criteria:

• Patients with supra- and sub tentorial neurosurgical pathology who meet the following inclusion criteria will be enrolled:
• Age greater than or equal to 18 years

Exclusion Criteria:

• Psychiatric illness in history and/or taking psychotropic drugs
• Glasgow Coma Score (GCS) < 15
• Presence of overt cognitive decline or speech disorders
• Patients younger than 18 years of age
• Intraoperative hypothermia (< 36°)
• Intraoperative hypotension (MAP < 20% of baseline)

Patients undergoing neurosurgical surgery afferent to the Department of Neurosurgery of the IRCCS Carlo Besta Neurological Institute Foundation will be consecutively enrolled from the date of study approval for 24 months.