INTRATHECAL MORPHINE FOR CORONARY-ARTERY BYPASS-GRAFTING AND EARLY EXTUBATION

Aggressive control of pain during the immediate postoperative period a fter cardiac surgery with early tracheal extubation may decrease morbi dity and mortality. This prospective, randomized, double-blinded, plac ebo-controlled clinical study examined the use of intrathecal morphine in patients undergoing cardiac surgery and its influence on early tra cheal extubation and postoperative analgesic requirements. Patients we re randomized to receive either 10 mu g/kg of intrathecal morphine (n = 19) or intrathecal placebo (n = 21). Perioperative anesthetic manage ment was standardized (intravenous (IV) fentanyl, 20 mu g/kg, and IV m idazolam, 10 mg) and included postoperative patient-controlled morphin e analgesia. Of the patients who were tracheally extubated during the immediate postoperative period, the mean time from intensive care unit arrival to extubation was significantly prolonged in patients who rec eived intrathecal morphine (10.9 h) when compared to patients who rece ived intrathecal placebo (7.6 h). Three patients who received intrathe cal morphine had extubation substantially delayed because of prolonged ventilatory depression. Although mean postoperative IV morphine use f or 48 h was less in patients who received intrathecal morphine (42.8 m g) when compared to patients who received intrathecal placebo (55.0 mg ), the difference between groups was not statistically significant. In conclusion, intrathecal morphine offers promise as a useful adjunct i n controlling postoperative pain in patients after cardiac surgery. Ho wever, the optimal dose of intrathecal morphine in this setting, along with the optimal intraoperative baseline anesthetic that will provide significant analgesia, yet not delay extubation in the immediate post operative period, remains to be elucidated.