Effect of dexmedetomidine on monitoring of motor evoked potentials in patients undergoing supratentorial craniotomy or brainstem surgery

INTERVENTION: Trade Name: Dexdor Pharmaceutical Form: Solution for infusion INN or Proposed INN: DEXMEDETOMIDINE CAS Number: 113775‐47‐6 Current Sponsor code: DEXDOR Concentration unit: µg/ml microgram(s)/millilitre Concentration type: up to Concentration number: 100‐ Pharmaceutical form of the placebo: Infusion Route of administration of the placebo: Intravenous use CONDITION: Patients scheduled for supratentorial craniotomy or brainstem surgery with intraoperative monitoring of motor evoked potentials (MEP). Therapeutic area: Analytical, Diagnostic and Therapeutic Techniques and Equipment [E] ‐ Anesthesia and Analgesia [E03] PRIMARY OUTCOME: Main Objective: During craniotomy procedures with monitoring of motor evoked potentials (MEP), we wanted to compare at baseline (before initiating craniotomy) the stimulation intensity and amplitude of MEP in patients allocated to receive either: propofol, remifentanil (PR group) or propofol,remifentanil,dexmedetomidine(PRD group) Primary end point(s): During craniotomy procedures with monitoring of motor evoked potentials (MEP), we wanted to compare at baseline (before initiating craniotomy) the threshold intensity and amplitude of MEP in patients allocated to receive either: propofol, remifentanil (PR group) or propofol,remifentanil,dexmedetomidine(PRD group) Secondary Objective: 1‐Propofol and remifentanil requirements; 2‐ Total consumption of propofol and remifentanil; 3‐ Latency and amplitude of somatosensory evoked potentials (SSEP); 4‐ Mean arterial pressure, heart rate, oxygen saturation (SpO2)and bispectral index (BIS); 5‐ Time to wake up from anaesthesia; 6‐ Side effects; 7‐ Postoperative analgesics requirements Timepoint(s) of evaluation of this end point: At thirty minutes, forty ‐ five minutes and sixty minutes after anaesthetic induction SECONDARY OUTCOME: Secondary end point(s): 1‐ Propofol (mg/kg/h) and remifentanil (ug/kg/min) requirements at baseline.; 2‐ Total doses of propofol (mg/kg/h) and remifentanil (ug/kg/min). ; 3‐ Latency and amplitude of somatosensory evoked potentials.; 4‐ Mean arterial pressure, heart rate, oxygen saturation by pulse oximetry, bispectral index.; 5‐ Time to wake up.; 6‐ Occurrence of side effects.; 7‐ Postoperative analgesics consumption.; ; Timepoint(s) of evaluation of this end point: 1‐ At baseline (before initiating craniotomy).; 2‐ From anaesthetic induction to the end of surgery.; 3‐ 30, 45, and 60 minutes after anaesthetic induction.; 4‐ Every 5 minutes during anaesthetic induction and surgery. Every 15 minutes in recovery room.; 5‐ From the end of surgery to the verbal response of the patient.; 6‐ During the study.; 7‐ Postoperative 24 h.; ; INCLUSION CRITERIA: 1‐ Male and females over 18 years. 2‐ Patients undergoing supratentorial craniotomy or brainstem surgery due to tumors located in these areas. 3‐ Patients who have given the informed written consent. Are the trial subjects under 18? no Number of subjects for this age range: F.1.2 Adults (18‐64 years) yes F.1.2.1 Number of subjects for this age range 10 F.1.3 Elderly (>=65 years) yes F.1.3.1 Number of subjects for this age range 10