ED₅₀ And ED₉₅ Of Intrathecal Bupivacaine Coadministered With Sufentanil For Cesarean Delivery Under Combined Spinal Epidural In Patients With Severe Preeclamsia

Background:Spinal anesthesia is considered a reasonable anesthetic option in patients with severe preeclampsia for cesarean delivery, when there is no contraindication or indwelling epidural catheter. However, the ideal dose of intrathecal bupivacaine in this scenario has not been determined.Methods:Two hundred patients with severe preeclampsia undergoing elective cesarean delivery under combined spinal-epidural anesthesia were enrolled in this randomized, double-blinded, dose-ranging study. Patients received 4mg,6mg,8mg, or 10mg intrathecal hyperbaric bupivacaine with 2.5μg sufentanil. Successful spinal anesthesia was defined as a T6 sensory level achieved within 10min after intrathecal drug administration with no need for epidural supplementation. The ED50 and ED95 were calculated with a logistic regression model.ResultsED50 and ED95 of intrathecal bupivacaine for successful spinal anesthesia were 5.67mg (95%CI,5.20-6.10mg) and 8.82mg (95%CI,8.14-9.87mg) respectively. The incidence of hypotension in Group 8mg and Group 10mg was higher than that in Group 4mg and Group 6mg (P<0.05). The sensory block was significantly different among groups 10min after intrathecal injection (P<0.05). The use of epidural lidocaine in Group 4mg was higher than that in other groups (P<0.05). The use of phenylephrine in Group 8mg and Group 1 Omg was higher than that in the other two groups (P<0.05). The lowest systolic blood pressure (SBP) before delivery of the infant in Groups 8 mg and 10 mg were lower than the other two groups (P<0.05). Muscle relaxation was less satisfactory in Group 4 mg compared to the other groups (p<0.05). There was no significant difference in patient satisfaction or newborn variables (Apgar score, umbilical artery blood gas) (p<0.05).ConclusionOur study showed that the ED50 and ED95 of intrathecal bupivacaine for severely pre-eclamptic patients undergoing elective cesarean delivery were 5.67mg and 8.82mg, respectively. In addition, decreasing the dose of intrathecal bupivacaine could reduce the incidence of maternal hypotension.