Multimodal Opioid-Free Anesthesia in RIRS

Opioids have traditionally been the cornerstone of perioperative analgesia; however, opioid-related adverse effects such as respiratory depression, postoperative nausea and vomiting (PONV), opioid-induced hyperalgesia, sedation, and delayed recovery may negatively affect postoperative outcomes. Opioid-free anesthesia (OFA) is a multimodal anesthetic approach that aims to provide adequate analgesia while minimizing or eliminating perioperative opioid exposure.

Dexmedetomidine and ketamine are commonly used components of OFA protocols. Dexmedetomidine provides sedation and analgesia through selective alpha-2 adrenergic receptor agonism without significant respiratory depression, whereas ketamine reduces central sensitization and opioid-induced hyperalgesia through NMDA receptor antagonism. Their combined use may provide synergistic analgesic and hemodynamic effects.

Retrograde intrarenal surgery (RIRS) is a minimally invasive endourological procedure commonly performed for renal stone disease. Rapid postoperative recovery and early discharge are important goals in this patient population. The use of laryngeal mask airway (LMA) may further facilitate smoother airway management and recovery.

This prospective, randomized, single-center, assessor-blinded clinical trial will compare a dexmedetomidine-ketamine based OFA protocol with conventional fentanyl-based anesthesia in adult patients undergoing elective RIRS under LMA. Eligible participants will be randomized in a 1:1 ratio to either the opioid-free anesthesia group or the opioid-based anesthesia group.

The primary outcomes are postoperative pain scores assessed using the Numeric Rating Scale (NRS) and postoperative opioid consumption during the early recovery period. Secondary outcomes include recovery characteristics, intraoperative hemodynamic parameters, quality of LMA removal, intraoperative patient movement, postoperative nausea and vomiting, surgeon satisfaction, and perioperative adverse events.

The investigators hypothesize that the OFA protocol may reduce postoperative opioid requirements and improve recovery quality while maintaining adequate perioperative analgesia and hemodynamic stability.