Study objective: To determine if intrathecal opioid decreases time to extubation after coronary artery bypass surgery without compromising postoperative analgesia.
Design: Prospective randomized trial.
Setting: Veterans Affairs Hospital.
Patients: 21 ASA physical status III and IV men scheduled for elective coronary bypass surgery, who had not received medications that would impair anticoagulation at the time of surgery.
Interventions: Patients were randomized to receive 10 micrograms/kg morphine and 25 micrograms fentanyl intrathecally preoperatively (n = 12) or no intrathecal opioid (n = 9). The latter group received 25 to 50 micrograms/kg fentanyl and 0.05 to 0.1 mg/kg midaxolam intraoperatively, whereas the intrathecal opioid group received intravenous (i.v.) fentanyl and midazolam only as needed. Both groups were administered i.v. morphine and midazolam postoperatively as needed by intensive care unit (ICU) personnel who were blinded to the treatment group.
Measurements and main results: For the first 24 hours postoperatively, pain levels (0 = none, to 10 = most severe) and sedation levels (1 = none, to 5 = unconscious) were measured hourly. The time to extubation and discharge from the ICU was recorded. ECG evidence of myocardial ischemia was noted. Pain scores were low for both groups (1.5), but the intrathecal opioid subjects exhibited less sedation than the high-dose fentanyl subjects [means +/- standard deviation (SD) of 2.3 +/- 0.4 vs. 2.8 +/- 0.5, p = 0.03]. Extubation time was 12 hours shorter in the intrathecal opioid group (2.9 +/- 5.3 vs. 14.7 +/- 6.8, p = 0.001). The five subjects with a one day ICU stay were all in the intrathecal opioid group (p = 0.04). The incidence of myocardial ischemia did not differ between the two groups.
Conclusions: Intrathecal opioid can facilitate early extubation and discharge from the ICU without compromising analgesia or increasing myocardial ischemia.