Intraoperative methadone for postoperative pain after laparoscopic hysterectomy: Protocol for a randomised, double-blind trial

Background Hysterectomy is often carried out as same-day surgery. Treatment of postoperative pain is, therefore, of utmost importance to ensure timely discharge from hospital. Methadone has several desirable pharmacological features, including a long elimination half-life. Theoretically, a single intraoperative dose could provide long-lasting pain relief. Methods This is a single-centre, investigator-initiated, randomised, double-blind study. Two-hundred and fifty women, scheduled to undergo hysterectomy at Horsens Region Hospital, Denmark, are randomized to receive methadone (0.2 mg/kg) or morphine (0.2 mg/kg) intraoperatively, 60 minutes before extubation. Primary outcomes are opioid consumption at 6 and 24 hours. Secondary outcomes include pain intensity at rest and during coughing at 1, 3, 6, 24 and 48 hours; patient satisfaction at 3 and 24 hours, postoperative nausea and vomiting at 6, 24 and 72 hours, adverse events in the postanaesthesia care unit (PACU) and time until readiness for discharge. Another outcome is persistent abdominal pain after 4 months. Conclusions The study outlined in this protocol will provide important information about the use of methadone in same-day hysterectomy patients. The results will presumably be applicable to other types of surgery involving visceral pain.