Safety and effectiveness of coadministration of intrathecal sufentanil and morphine in hyperbaric bupivacaine-based spinal anesthesia for cesarean section.

Subarachnoid block is a widely used technique for cesarean section. Opioids adding to the local anesthetics can improve its quality. In this prospective, randomized, double blind, controlled trial, we compared the effects of coadministration of intrathecal sufentanil and morphine with intrathecal sufentanil and a single administration of subcutaneous morphine. Sixty-four pregnant women scheduled for elective cesarean section under spinal anesthesia were assigned to two groups according to the way of administration of morphine: intrathecal sufentanil (5 microg) plus intrathecal morphine (150 microg) (ITM group), and intrathecal sufentanil (5 microg) plus single administration of 10 mg subcutaneous morphine (SCM group). In both groups, the local anesthetic used was hyperbaric bupivacaine 0.5 percent (10 mg). Both groups received 1 g acetaminophen every 6 hours. In the postoperative period, pain was recorded on a 0-100 visual analog scale (VAS) and intravenous tramadol (100 mg) was administered if VAS score was >40 mm. Collateral effects, such as nausea, itching, respiratory depression, and sedation were assessed. VAS scores at rest and on coughing were significantly higher in the SCM group than in the ITM group between 3 and 24 hours. The mean titrated dose of tramadol consumed was also significantly greater in the SCM group than in the ITM group (p < 0.05). The time to first administration of tramadol was lower in the SCM group versus the ITM group (p < 0.05). The incidence of nausea was significantly lower in the SCM group than in the ITM group (p < 0.05). There was no significant group difference in the incidence of pruritus (p > 0.05). In conclusion, coadministration of sufentanil and morphine into the subarachnoid space was effective and provided longer pain relief than intrathecal sufentanil plus a single injection of subcutaneous morphine, despite a higher incidence of side effects such as nausea and vomiting.