Effect of subarachnoid morphine administration on extubation time after coronary artery bypass graft surgery.
OBJECTIVE
To determine the effects of 2 low doses of intrathecal morphine on extubation time and on postoperative analgesic requirements after coronary artery bypass graft (CABG) surgery.


METHODS
A prospective, randomized, double-blind, placebo-controlled study.


METHODS
Tertiary-care university hospital.


METHODS
Fifty adult patients scheduled for elective primary CABG surgery.


METHODS
Patients were randomized to receive placebo, 250 microg, or 500 microg intrathecal morphine, preoperatively. Intraoperative fentanyl and midazolam were limited to 15 microg/kg and 20 microg/kg intravenously. Patients were extubated in the intensive care unit by a blinded observer using predefined extubation criteria.


RESULTS
Time to extubation and postoperative requirements for morphine, midazolam, nitroglycerin, and sodium nitroprusside were recorded by a blinded observer. Extubation times were 441 +/- 207 minutes versus 325 +/- 188 minutes versus 409 +/- 245 minutes for the placebo, 250-microg, and 500-microg groups (p = 0.27). Postoperative morphine requirements in the 250-microg and 500-microg groups were 13.6 +/- 7.8 mg and 11.7 +/- 7.4 mg, compared with 21.3 +/- 6.2 mg in the placebo group (p = 0.001). There were no differences among the study groups with regard to postoperative midazolam, nitroglycerin, and sodium nitroprusside requirements.


CONCLUSIONS
Despite decreased postoperative morphine requirements, intrathecal morphine administration did not have a clinically relevant effect on extubation time after CABG surgery. This study suggests that 250 microg is the optimal dose of intrathecal morphine to provide significant postoperative analgesia without delaying tracheal extubation.
Alhashemi
J A
JA
London Health Sciences Centre University of Western Ontario, Canada.
Sharpe
M D
MD
Harris
C L
CL
Sherman
V
V
Boyd
D
D
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001026:Coronary Artery Bypass; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D007442:Intubation, Intratracheal; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D010100:Oxygen / Q000097:blood; D011183:Postoperative Complications / Q000139:chemically induced; D011446:Prospective Studies; D013346:Subarachnoid Space; D016896:Treatment Outcome
D000701:Analgesics, Opioid; D009020:Morphine; D010100:Oxygen