Epidural Morphine for Postoperative Pain Relief

Abstract

The relatively new technique of epidural morphine analgesia was compared with two well established methods of pain relief in 90 patients undergoing gallbladder surgery and divided randomly into three groups of 30 patients each. The first group received intramuscular narcotic analgesic ketobemidone, the second group was given 0.5% bupivacaine-epinephrine intercostal nerve block, and the third group received a single dose of 4 mg of epidural morphine for postoperative pain relief. The mean duration of analgesia after ketobemidone was 5.5 hours, and after intercostal block 11 hours. Of the patients given epidural morphine, 40% did not require further analgesia after the initial injection; the remaining patients in this group were pain free for a mean duration of 19 hours. The mean reduction in postoperative peak expiratory flow was most marked following ketobemidone and least after epidural morphine. Postoperative changes in PaO2 and PaCO2 reflected the changes in peak expiratory flow. Plasma levels of morphine after epidural injection were so low that a regional spinal analgesic action of epidural morphine appeared more likely than a systemic effect. Delayed respiratory depression was not encountered after epidural morphine. It is concluded that a single dose of 4 mg of epidural morphine provides excellent regional analgesia of long duration without drowsiness or circulatory or respiratory depression, thus facilitating early ambulation. The technique is superior to more common methods of pain relief after gallbladder surgery, e.g., intercostal nerve block and intramuscular narcotics.