Study objective: To compare the analgesic and side effects of preemptively used epidural ketamine +bupivacaine, neostigmine +bupivacaine, and bupivacaine alone on postoperative analgesia after major abdominal surgery.
Design: Randomized, controlled study.
Setting: Inpatient anesthesia at the department of surgery of a metropolitan hospital.
Patients: 30 ASA physical status I, II, and III patients scheduled for abdominal surgery.
Interventions: Group K received 1 mL (50 mg) ketamine and 5 mL (25 mg) bupivacaine epidurally, Group N received 1 mL (0.5 mg) neostigmine and 5 mL (25 mg) bupivacaine epidurally, and Group B received 1 mL saline and 5 mL (25 mg) bupivacaine epidurally 30 minutes before operation. All patients underwent anesthesia induction with thiopental and vecuronium; anesthesia was maintained with isoflorane and vecuronium. For postoperative analgesia, all patients received epidural morphine for 48 hours postoperatively.
Measurements and main results: Standard monitoring included: 48 hours of analgesic requirement, visual analog scale (VAS), mean arterial pressure (MAP), and heart rate (HR) in the 1st, 2nd, 6th, 12th, 24th, and 48th hours. Data were analyzed using Kruskall-Wallis and Mann Whitney U tests, with a p < 0.05 considered statistically significant. No significant differences were observed regarding MAP and HR among the groups during the study period. In Group N, VAS was significantly lower than Group K and Group B. The total opioid consumption in Group N was significantly lower than in Groups K and B in the first 48 hours after the operation.
Conclusions: Preemptive neostigmine can be a good choice for postoperative analgesia.