Comparison of efficacy of opioid-free anaesthesia with opioid-based anaesthesia in patients undergoing middle ear surgery:a randomised controlled study

Opioids are frequently utilized under anaesthesia; however, they are associated with side effects that includes nausea, vomiting, hypotension, respiratory depression/apnoea, bradycardia, somnolence, urinary retention, constipation and cancer recurrence etc. In recent years, the concept of opioid-free anaesthesia (OFA) has emerged. Opioid-free anaesthesia has been found to be as efficacious as conventional opioid-based anaesthesia (OBA) in terms of decreased incidence of post-operative nausea and vomiting (PONV) and comparable pain management. On literature search, no study has evaluated strict OFA regimen for middle ear surgery. Patients will be randomly allocated into one of the two groups. Patients in group OB will receive conventional opioid-based anaesthesia. Patients in group OF will receive opioid-free anaesthesia. For providing OFA, patients will receive dexmedetomidine infusion pre-induction at 0.5 mcg/kg over 10 minutes and then at the rate of 0.3-0.7mcg/kg/hr. Ketamine at the rate of 0.25-0.5mg/kg/hr will be administered intravenously for providing analgesia and hemodynamic stability during surgery. The infusions will be stopped approx. 30 mins before completion of surgery. The primary outcome is incidence of PONV in 0-12 h time interval. The secondary outcomes are  PONV at 0-6th hr, 6th -12th hr, 12th -24th hr and 24th-48th hr between the two groups, Severity of PONV using Nausea score at 0-48 h, Pain intensity using NRS-Pain at Rest and Cough at 0-3 h,3-6 h, 6-12 h, 12-24 h, 24-48 h, Total rescue antiemetics consumption in the first 24 hours, Rescue analgesic consumption in the first 24 hours, QoR-15 score,intraoperative and post-operative haemodynamic parameters, Time to Aldrete score ≥9, Adverse events like constipation, urinary retention, pruritus, postoperative ileus etc.