Interpleural Morphine vs Bupivacaine for Postthoracotomy Pain Relief

Abstract

This prospective randomized double-blind trial was designed to compare the analgesic effects of interpleural bupivacaine and interpleural morphine for postthoracotomy pain management. Thirty-six American Society of Anesthesiologists class I and II patients undergoing an elective posterolateral thoracotomy were randomly divided into 2 groups of 18 each. Before chest closure, an interpleural catheter was inserted under direct vision. At the end of the operation and every 4 hours thereafter, they received either 0.25% bupivacaine with epinephrine or 0.2 mg·kg⁻¹ morphine sulfate interpleurally for 24 hours. The chest tubes were clamped during injection and for 15 min afterwards. Supplementary doses of intravenous morphine were given on request. The pain severity was evaluated at rest and on coughing before and 30 min after each interpleural injection, using an 11-point visual analog scale. Supplemental analgesic consumption and side effects were recorded. Both interpleural morphine and bupivacaine significantly reduced pain scores 30 min after each injection. However, pain scores and supplementary analgesic requirements were significantly lower in the interpleural morphine group. No serious side effects were detected in either group. Interpleural morphine provides better pain control than interpleural bupivacaine after a posterolateral thoracotomy.