The efficacy of intrathecal coadministration of morphine and bupivacaine for labor analgesia.
BACKGROUND
Intrathecal (i.t.) opioids can provide labor analgesia, but the onset of pain relief is slow. Bupivacaine has the beneficial property of less motor blockade than other local anesthetics. This study retrospectively examined the efficacy of concomitant use of i.t. morphine and bupivacaine for labor pain relief.


METHODS
Fifty five nulliparas who requested analgesia in the active phase (IA group) prior to a cervical dilation 3.9 +/- 0.6 cm and received i.t. morphine 0.5 mg and 0.1% bupivacaine 2.5 mg served as the treatment group, and 88 similar nulliparas who did not request and receive analgesia served as the control group.


RESULTS
The mean onset time of analgesia was 2.6 +/- 0.5 min, the duration was 4-12 h and 93% of parturients did not request additional analgesia after a single injection of i.t. morphine and bupivacaine. The active phase of the first and second stages of labor in the treatment group were significantly longer [318 +/- 214 min vs. 176 +/- 120 min; 74 +/- 29 min vs. 37 +/- 26 min]. Frequency of instrument-assisted vaginal delivery was higher compared with the control group (30.9% vs. 14.1%). However, there were no significant differences in the rate of cesarean section and the Apgar scores of newborns at 1 min and 5 min between the treatment and control group. The major side effects of the treatment group included pruritus (48%), nausea (40%), vomiting (37%), somnolence (27%), shivering (27%), urinary retention (21%), hypotension (15%), and bradycardia (13%). Most of the side effects were mild and could be alleviated by naloxone. Neither post-spinal headache nor respiratory depression was noted.


CONCLUSIONS
Our results showed that a single injection of i.t. morphine and bupivacaine provided rapid onset and effective analgesia with manageable side effects and without major complications. Thus, i.t. morphine and bupivacaine provides an alternative to epidural analgesia for most women in labor.
Wu
J L
JL
Department of Anesthesiology, Taiwan Provincial Poutzu Hospital, R.O.C.
Hsu
M S
MS
Hsu
T C
TC
Chen
L H
LH
Yang
W J
WJ
Tsai
Y C
YC
D000328:Adult; D016362:Analgesia, Obstetrical; D000701:Analgesics, Opioid / Q000008:administration & dosage*; D002045:Bupivacaine / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007231:Infant, Newborn; D007278:Injections, Spinal; D009020:Morphine / Q000008:administration & dosage* / Q000009:adverse effects; D011247:Pregnancy; D012189:Retrospective Studies
D000701:Analgesics, Opioid; D009020:Morphine; D002045:Bupivacaine