Baricity, needle direction, and intrathecal sufentanil labor analgesia

Background: Intrathecal sufentanil relieves labor pain but centrally mediated side effects are common, Preventing rostral spread of intrathecal 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 intrathecal sufentanil labor analgesia. Methods: Forty laboring, full-term parturients, whose cervixes were dilated less than 5 cm and who requested analgesia for labor were enrolled. Combined spinal epidural analgesia 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 directed cephalad or caudad during drug injection, Thus there were four groups 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 scores 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, Sufentanil 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 groups requested additional analgesia by 30 min. Conclusions: Little or no labor analgesia developed for patients receiving sufentanil with dextrose, A supraspinal action may contribute to intrathecal sufentanil's analgesic efficacy.