Intrathecal morphine in aortic aneurysm surgery.

The purpose of this study was to compare the peri-operative conditions produced by intrathecal morphine with those that result from conventional analgesia in aortic aneurysm surgery. Low-dose intrathecal morphine provides a level of analgesia during operation indistinguishable from that of moderate doses of parenteral opiate, but is no more effective in attenuating autonomic responses to the procedure. Analgesia is prolonged into the postoperative period, does not cause clinically evident respiratory depression and can be enhanced by small doses of intravenous opiate. The principal advantage of intrathecal morphine is the avoidance of irregular and inadequate pain relief in the early, and most painful, part of the postoperative period. Low-dose intrathecal morphine appears safe, effective and feasible in aortic aneurysm surgery and provides an alternative to traditional management with parenteral opiates.