Type of Study: interventional, randomized and double-blinded controlled trial. Study Setting: The operating theatres of Ain Shams University Hospitals. Study Period: over one year.
Study Procedures
Patients will be randomly allocated by computer generated randomization and using opaque sealed envelopes to one of the two groups according to the used analgesia into:
o Group Traditional balanced anesthesia (TBA): Analgesia will be provided by fentanyl in induction and maintenance according to Ideal Body Weight (IBW)
o Group Opioid free anesthesia (OFA): Analgesia will be provided by syringe containing ketamine, Lidocaine and Dexmedetomidine in induction and maintenance according to lean body weight (LBW).
Both groups will receive port site infiltration with bupivacaine 0.25% 20 ml.
Pre-operatively, all patients will receive Ondansetron 4 mg IV, and metoclopramide 10 mg intravenously (IV).
After proper assessment of the airway and anticipation of difficult airway, all patients will receive midazolam 2 mg IV for sedation and we will start pre-oxygenation with 100% O2 on 8 L/min for 3 min via face mask.
All patients will receive general anesthesia induction by propofol 1.5-2 mg/kg (LBW), analgesia according to patient group, and muscle relaxation by atracurium 0.5 mg/Kg LBW to facilitate endotracheal intubation. Anesthesia will be maintained by isoflurane whose concentration will be adjusted according to patient's hemodynamics. Analgesia used in the study will be prepared in the pharmacy and will be given a code so that the anesthetist in charge will be blinded to the randomisation group and the analgesia used. The analgesia will be prepared as follows:
* Fentanyl 2 mg/kg (LBW) as induction dose in 10 ml syringe to be given over 10 minutes, and 1 mg/kg/h in 50 ml syringe as infusion during operation starting before skin incision for Group TBA.
* Group OFA :
Induction :
Ketamine: 0.5 mg/kg (IBW), Lidocaine 1 mg/kg and dexmedetomidine 0.5 mg/kg (LBW) for induction to be given in 10 ml syringe over 10 minutes.
Maintenance : The maintenance mixture" - 50 cc syringe containing:
50 mcg Dexmedetomidine (0.5 cc of standard 100 mcg/ml solution) 50 mg Ketamine 500 mg Lidocaine (25 ml of standard 2% solution) NaCl up to total 50 ml. Ketamine 0.1 mg/kg/h (IBW), Lidocaine 1 mg/kg/h and dexmedetomidine 0.1 mg/kg/h (LBW) as infusion during operation starting before skin incision. (1ml/10 kg of solution from "The maintenance mixture" syringe ) After skin preparation and before port insertion, 20 ml of 0.25% bupivacaine solution was infiltrated through the abdominal wall 4ml around each port site in both groups.
About 15 min before the end of the operation reduce maintenance dose to 0.5 ml/10 kg/h Ventilator Settings: the ventilation will be achieved with a volume-controlled mode ventilation, respiratory rate adjusted according to EtCO2 to range between 35-45 mmHg, a tidal volume of 6-8 ml/kg and mixture of gases in proportion 50% oxygen and 50% air, with PEEP 5 cm H2O using a closed circle system and with a total fresh gas flow rate of 3L/min.
Analgesic infusion will be stopped after skin closure. Paracetamol 1 gm and diclofenac 75 mg (incorporated in IV infusion fluids) will be given intra-operatively before emergence.
At the end of surgery, muscle relaxation will be reversed with neostigmine (up to 5 mg) and atropine (up to 2 mg).
These procedures will be done by supervisors and experts. Patients will be kept after extubation for observation in PACU until fulfilling an Aldrete score of 9.
Patients will receive metoclopramide 10 mg intravenously (IV) and Ondansetron 4 mg IV as post-operative nausea and vomiting (PONV) treatment.
Post-operative analgesia will be offered in regular doses of paracetamol 1 gm IV every 6 hours for the following 24 hours, and rescue doses of IV nalbuphine 5 mg (Up to 20 mg max/dose). If VAS score is \>3.
The anesthetist evaluating outcomes in PACU and in the ward will not participate in the anesthesia and will not be aware of the randomisation group.
