Propofol-Fentanyl-Dexmedetomidine and Propofol-Fentanyl-Sevoflurane Anesthesia for Major Spine Surgery Under Somato Sensory- and Motor- Evoked Potential Monitoring

Anesthesia will be induced with propofol (2mg/kg) and fentanyl (1 ug/kg). Anesthesia will be maintained with propofol and fentanyl infusion, commenced at 10 mg/kg/hr and 0.5 ug/kg/hr respectively and adjusted to keep BIS between 40 \& 50 during surgery. Minimal dose of atracurium 0.1 mg/kg will be given at induction to facilitate intubation.

"Anesthesia will be induced with propofol (2mg/kg) and fentanyl (1 ug/kg). Anesthesia will be maintained with propofol and fentanyl infusion, commenced at 10 mg/kg/hr and 0.5 ug/kg/hr respectively and adjusted to keep BIS between 40 \& 50 during surgery.~In addition patients will receive Dexmedetomidine (0.5ug.kg) loading dose infused over 10 mins followed by a constant infusion rate of (0.2ug/kg/hr). Minimal dose of atracurium 0.1 mg/kg will be given at induction to facilitate intubation."

"Anesthesia will be induced with propofol (2mg/kg) and fentanyl (1 ug/kg). Anesthesia will be maintained with propofol and fentanyl infusion, commenced at 10 mg/kg/hr and 0.5 ug/kg/hr respectively and adjusted to keep BIS between 40 \& 50 during surgery.~In addition the anesthesia will be maintained with inhalational anesthesia of 50% oxygen , 50% air plus sevoflurane concentration adjusted to keep BIS between 40 \& 50 . Minimal dose of atracurium 0.1 mg/kg will be given at induction to facilitate intubation"