D 1 at the end of surgery provides the best quality of emergence from general anesthesia including the control of cough, agitation, hypertension, tachycardia, and shivering. D 0.5 also controls emergence phenomena but is less effective in controlling cough. The 3 doses do not delay extubation. However, they cause dose-dependent hypotension.

Background: The aim of this study is to compare the intraoperative opioid free anesthesia approach to the conventional opioid based anesthesia in patients undergoing multilevel spinal fusion surgery, and its impact on postoperative pain, opioid consumption, and related side effects. Methods: Forty-eight patients undergoing elective major spine surgery were randomly allocated to two groups. The Opioid-Free Anesthesia (OFA) group received dexmedetomidine 0.5mcg/kg/hr and lidocaine 1mg/kg/hr as continuous intravenous (IV) infusion for 10 minutes before anesthesia induction, followed by dexmedetomidine 0.3 mcg/kg/hr and lidocaine 1.5mg/kg/hr as continuous IV infusion intraoperatively. The Opioid-Based Anesthesia (OBA) group received fentanyl 2mcg/kg during anesthesia induction and remifentanil 0.2-0.3 mcg/kg/min continuous IV infusion intraoperatively. All patients received ketamine 0.15mg/kg, propofol 2 mg/kg and rocuronium 0.6 mg/kg for anesthesia induction and ketamine 0.15 mg/kg/hr with sevoflurane for anesthesia maintenance. All patients received a Patient Controlled Analgesia (PCA) device set to deliver IV morphine ready for use directly after discharge from the Post Anesthesia Care Unit (PACU) for 48 hours after surgery. Postoperative pain was measured using Verbal Analogue Scale (VAS). Opioid side effects were documented when present. Results: The OFA group required less morphine consumption in the first 24 hours post-surgery (17.28 ± 12.25 mg versus 27.96 ± 19.75 mg, p < 0.05). The incidence of nausea and vomiting was significantly lower in the OFA group. There was no significant difference in the hemodynamic changes intraoperatively among the two groups. However, more patients in the OFA group required antihypertensive medications compared to patients in the OBA group (p< 0.05). In the PACU, OFA patients had a significantly longer stay than OBA patients (114.1± 49.33 min versus 89.96 ± 30.71 min, p<0.05), yet there was no significant difference in the morphine consumption. Conclusion: OFA can be an alternative to OBA in patients undergoing multilevel spine fusion surgery. OFA use resulted in reduced need for analgesics for the first 24 hours and less postoperative nausea and vomiting. Trial registration: The study was conducted after receiving approval from local Institutional Review Board, Lebanese American University, Institutional Review Board (LAU IRB) (LAUMCRH.HB1.11/01/2018): and was registered with ClinicalTrials.gov (registration number: NCT03417193) and posted on 31/01/2018.