Comparison of intraoperative fentanyl with dexmedetomidine for perioperative analgesia and opioid consumption during craniotomies: A randomised controlled pilot study with non‐inferiority design

BACKGROUND: Moderate to severe pain is common despite the use of potent opioids during craniotomies. Non-opioid agents such as dexmedetomidine reduce undesirable opioid effects and are successfully used as primary analgesic during bariatric surgeries. This study assessed the feasibility of conducting a large randomised controlled trial comparing fentanyl with dexmedetomidine for perioperative analgesia during craniotomy. METHODS: This was a prospective single-centre randomised controlled feasibility trial. Twenty-four consenting adult patients undergoing supratentorial craniotomy at NIMHANS, Bangalore, India, were recruited after ethical approval in March and April 2018. They received either fentanyl 1 µg kg^-1  h^-1 (n = 12) or dexmedetomidine 0.5  µg kg^-1  h^-1 (n = 12) as primary intraoperative analgesic drug. Patient, anaesthesiologist, outcome assessor and data analyst were blinded to the study intervention. Our feasibility outcomes (primary) were recruitment and adherence rates. We also explored the potential efficacy of intervention and adverse events. RESULTS: We recruited 24 out of 30 eligible patients and had 100% protocol adherence, thereby demonstrating the feasibility of a larger randomised controlled trial. All 24 patients completed the study. The demographic and clinical parameters were similar between the groups. Compared between fentanyl and dexmedetomidine, there was no difference in the intraoperative fentanyl (top-up) consumption (µg), expressed as median and interquartile range: 25 (0-50) and 0 (0-50); P = 0.844; and no difference in postoperative pain at 15 and 60 minutes. Adverse events were few and similar with fentanyl and dexmedetomidine. CONCLUSIONS: A large-scale randomised controlled trial of perioperative dexmedetomidine versus fentanyl is feasible. Dexmedetomidine has the potential to be non-inferior to fentanyl for perioperative analgesia during craniotomies.