Background: Intrathecal sufentanil relieves labor pain but centrally m
ediated side effects are common, Preventing rostral spread of intrathe
cal sufentanil should limit these side effects, Both direction of the
lateral opening of a pencil-point needle and drug baricity modify the
spread of intrathecal local anesthetics. This randomized, prospective,
double-blind study examines the effects of these variables on intrath
ecal sufentanil labor analgesia. Methods: Forty laboring, full-term pa
rturients, whose cervixes were dilated less than 5 cm and who requeste
d analgesia for labor were enrolled. Combined spinal epidural analgesi
a was induced in patients in the sitting position. They were allocated
to receive 10 mu g intrathecal sufentanil diluted with either normal
saline or dextrose with the aperture of the pencil-point needle direct
ed cephalad or caudad during drug injection, Thus there were four grou
ps of ten patients: dextrose up, dextrose down, saline up, and saline
down, Sufentanil was diluted with normal saline to a concentration of
10 mu g/ml. The study drug was made by mixing 1 ml sufentanil solution
with either 1 ml 10% dextrose or 1 ml normal saline. Visual analog sc
ores for pain, pruritus, nausea, and pain relief were recorded before
and 5, 10, 15, and 30 min after drug injection. Results: Baricity, but
not needle orientation, influenced pain relief and pruritus, Sufentan
il in dextrose produced less itching but also less analgesia. Nine of
20 women in the dextrose groups compared with 1 of 20 in the saline gr
oups requested additional analgesia by 30 min. Conclusions: Little or
no labor analgesia developed for patients receiving sufentanil with de
xtrose, A supraspinal action may contribute to intrathecal sufentanil'
s analgesic efficacy.