Non-opioid versus Opioid Peri-operative Analgesia In Neurosurgery (NOPAIN): Study protocol for a multi-centric randomised controlled trial.

Background and Aims: Many patients suffer from post-operative pain after neurosurgery despite using intra-operative opioids. Opioid side effects are problematic in neurosurgical patients. Hence, non-opioid alternatives for the management of nociception and pain are needed. Previous studies comparing opioids with non-opioids in the neurosurgical population were few, from single centres, of small sample sizes and were equivocal in findings, which prevented change in clinical practice. To overcome these limitations, we are conducting a multi-centre trial with objectives to compare intra-operative rescue opioid requirements and post-operative pain scores (primary objectives), adverse events, quality of recovery from anaesthesia, quality of sleep and patient satisfaction during hospital stay, and persistent post-surgical pain and quality of life at 3 and 6 months (secondary objectives) in patients receiving opioid and non-opioid analgesia for brain tumour surgeries. Methods: This study protocol describes the methodology of a multi-centre randomised controlled trial. Ethics committee approval has been obtained from all five centres, the trial has been registered with the Clinical Trial Registry- India, and insurance has been obtained for this investigator-initiated funded study. In patients undergoing supra-tentorial brain tumour surgery (population), we will compare fentanyl (intervention) 1 µg/kg/h with dexmedetomidine (comparator) 0.5 µg/kg/h administered during surgery with regards to intra-operative rescue opioid requirement and post-operative pain (primary outcomes). Results: We describe the study protocol of the multi-centre trial (protocol version 2, dated 29/01/2022). The first patient was recruited on 19/10/2022, and we will complete recruitment before March 2024. Conclusion: We expect our study to establish dexmedetomidine as an effective non-opioid analgesic vis-à-vis opioids in the neurosurgical population.