Evaluation of Efficacy of Free Opioid Anesthesia for Laparoscopic Cholecystectomy: A Prospective, Randomized Double-blinded Study

To evaluate efficacy and side effects of free opioid anesthesia for laparoscopic cholecystectomy.

A prospective study was performed on 94 patients undergoing laparoscopic cholecystectomy in Military Hospital 103 from May 2018 to February 2019. These patients were randomly allocated into two groups: patients in FOA (free - opioid anesthesia) group were administered lidocaine (2 mg/kg before induction and 1.5 mg/kg/h for maintenance), magnesium (30 mg/kg before induction and 1.5 g infusion for maintenance) combined with Intravenous (IV) injection of ketamine (0.5 mg/kg), and ketorolac (30 mg); while patients in OA group (opioid anesthesia) were provided with IV fentanyl (5 mcg/kg for induction and 1.5 mcg/kg every 30 minutes for maintenance of anesthesia). Both groups received total intravenous anesthesia by propofol. The depth of anesthesia was monitored by the entropy module during surgery. Neuromuscular blockade was reversed by sugammadex 2 mg/kg at the end of surgery. The postoperative analgesia was delivered using IV fentanyl for 48 to 72 hours. Visual Analog Scale (VAS) score was measured 10 mins, 20 mins, 1 hour, 2 hours and 3 hours after surgery.

All patients had an excellent quality of anesthesia with RE (Respond Entropy), SE (State Entropy) always under 60 from induction to abdominal closure without intraoperative awareness and postoperative recall of the operation; 100% of the patients were extubated immediately after surgery. In the first three postoperative hours fentanyl consumption in Group FOA was significantly lower than in Group OA (31.91 ± 3.98 mcg versus 34.47 ± 7.17 mcg, p=0,035). In the OA group, the rate of intraoperative hypotension was higher compared to its counterpart. Despite the higher risk of hypersalivation, group FOA had a significantly lower incidence of nausea and vomiting.

Free opioid anesthesia provided adequate sedation and amnesia and may be an alternative approach to opioid anesthesia for laparoscopic cholecystectomy. Patients under free opioid anesthesia experienced a lower incidence of intraoperative hypotension, lower rate of nausea, vomiting and lower demand for analgesia in the early postoperative period (0 - 3 h) compared to those receiving opioid anesthesia.