Opioid Free Anesthesia in Obese Patients.

Group (A): Induction of general anesthesia will be done using lidocaine (1.5 mg/kg), propofol (2-3 mg/kg), and atracurium (0.5 mg/kg). Dexmedetomidine 0.5 µg/kg over 10 min, started 10 min before induction. Following tracheal intubation, dexmedetomidine infusion generally will be initiated at 0.6 μg/kg/h and titrated between 0.2 and 1.0 μg/kg/h according to the heart rate maintaining bispectral index (BIS) between 40-60, lidocaine (1.5 mg/kg/h). ketamine will be given as a bolus dose of 0.3 mg/kg after induction and prior to skin incision then 0.2 mg/kg/h as an infusion. Patients will receive dexamethasone (8 mg i.v.) after induction.

In group (B) for induction of anesthesia, patients will receive propofol 2-3mg/kg, fentanyl 1-2mcg/kg and atracurium 0.5 mg/kg as a muscle relaxant to facilitate intubation. Fentanyl bolus doses of 0.5-1 mcg/kg will be given to keep BIS score 40-60 during surgery.