Low dose intrathecal morphine facilitates early extubation after cardiac surgery: results of a retrospective continuous quality improvement audit

To document one centre's experience with a multimodal analgesic approach, with or without low dose intrathecal morphine (ITM), in facilitating "fast-track" recovery in patients undergoing cardiac surgery.Records of 131 consecutive patients who underwent first time elective cardiac surgery during a four-month period in 2000 were reviewed. Patients were divided into two groups: those receiving and those not receiving preoperative low dose ITM (5 microgxkg(-1)) as part of a multimodal analgesic technique. Demographic and surgical characteristics, postoperative morphine use, time to extubation and requirement for antiemetics were recorded.Overall, 75% of patients were extubated within two hours, and 93% within six hours. Fifty-five patients received, and 76 did not receive, ITM (mean +/- SD 259 +/- 53 microg) along with a multimodal analgesic technique (parasternal infiltration, acetaminophen and indomethacin, and postoperative i.v. morphine). Anesthetic technique involved modest dose opioids, volatile agent and propofol infusion. The groups were similar with respect to preoperative, intraoperative and anesthetic characteristics. Mean extubation time for fast-track patients receiving vs not receiving ITM was 75 +/- 65 vs 117 +/- 85 min (P = 0.003). Intravenous morphine use for the first 12 hr after surgery was also reduced in the ITM group (4.6 +/- 4.1 vs 10.0 +/- 14.8 mg, P = 0.009). There was no difference in rescue antiemetic or antipruritic requirements, failed fast-tracking, or serious adverse events.Multimodal postoperative analgesia allowed for uneventful early extubation and low opioid requirements. Low dose ITM further facilitated early extubation, and reduced postoperative analgesic requirements.