Intrathecal Morphine for Postoperative Pain Relief

Summary We injected 0.1 to 3 mg of morphine and atropine morphine added to 0.3% dibucaine solution into the lumbar subarachnoid space of 101 patients for supplementary intraoperative anesthesia and postoperative analgesia. Pain relief occurred within 20 to 40 minutes after injection and lasted 6 to 59 hours, with a mean duration of 25 hours, in 65 patients; the remaining 36 patients obtained unlimited pain relief for over 72 hours. However, increasing the intrathecal dose of morphine to 3 mg did not increase the duration of the analgesia. Respiratory depression was observed in 5 patients who had recieved 1.5 to 3 mg of morphine and atropine morphine. Four of these patients developed delayed respiratory depression 5 to 8 hours after the injection, and one developed early respiratory depression 1 hour after the injection. All required treatment. Other systemic side effects such as itching, nausea and vomiting occurred in a high proportion of the patients. However, in the majority of cases, these side effects were mild. A good euphoric mood appeared in 6 patients. Our experience, although limited, is that intrathecal morphine can be simultaneously used with local anesthetics effectively, safely and simply. But the optimal dose has yet been determined, and requires further investigation.