title: Intrathecal magnesium sulfate does not reduce the ED50of intrathecal hyperbaric bupivacaine for cesarean delivery in healthy parturients: a prospective, double blinded, randomized dose-response trial using the sequential allocation method.
abstract: Addition of intrathecal magnesium sulfate to local anesthetics has been reported to potentiate spinal anesthesia and prolong analgesia in parturients. The current study was to determine whether intrathecal magnesium sulfate would reduce the dose of hyperbaric bupivacaine in spinal anesthesia with bupivacaine and sufentanil for cesarean delivery.
  
  
  
  Sixty healthy parturients undergoing scheduled cesarean delivery were randomly assigned to receive spinal anesthesia with 0.5% hyperbaric bupivacaine and 5 μg sufentanil with either 0.9% sodium chloride (Control group) or 50% magnesium sulfate (50 mg) (Magnesium group). Effective anesthesia was defined as a bilateral T5sensory block level achieved within 10 min of intrathecal drug administration and no additional epidural anesthetic was required during surgery. Characteristic of spinal anesthesia and the incidence of side effects were observed. The ED50for both groups was calculated using the Dixon and Massey formula.
  
  
  
  There was no significant difference in the ED50of bupivacaine between the Magnesium group and the Control group (4.9 mg vs 4.7 mg) (P = 0.53). The duration of spinal anesthesia (183 min vs 148 min, P < 0.001) was longer, the consumption of fentanyl during the first 24 h postoperatively (343 μg vs 550 μg, P < 0.001) was lower in the Magnesium group than that in the Control group.
  
  
  
  Intrathecal magnesium sulfate (50 mg) did not reduce the dose requirement of intrathecal bupivacaine, but can extend the duration of spinal anesthesia with no obvious additional side effects.
  
  
  
  This study was registered with Chinese Clinical Trial Registry (ChiCTR) on 15 Jul. 2014 and was given a trial ID number ChiCTR-TRC- 14004954 .
authors.affiliation: Department of Anesthesia, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China.|Department of Anesthesia, Jiaxing Maternity and Child Care Hospital, Jiaxing, Zhejiang, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Xiao
authors.affiliation: Department of Anesthesia, Jiaxing Maternity and Child Care Hospital, Jiaxing, Zhejiang, China.
authors.forename: Wenping
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Anesthesia, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Department of Anesthesia, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Fu
authors.affiliation: Department of Anesthesia, Jiaxing Maternity and Child Care Hospital, Jiaxing, Zhejiang, China.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Anesthesia, Jiaxing Maternity and Child Care Hospital, Jiaxing, Zhejiang, China.
authors.forename: Yinfa
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Anesthesia, Jiaxing Maternity and Child Care Hospital, Jiaxing, Zhejiang, China.
authors.forename: Lizhong
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Anesthesia, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China. chenxinz@zju.edu.cn.
authors.forename: Xinzhong
authors.initials: X
authors.lastname: Chen
mesh_terms: D000328:Adult; D000773:Anesthesia, Obstetrical / Q000379:methods*; D000775:Anesthesia, Spinal / Q000009:adverse effects / Q000379:methods; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D002045:Bupivacaine / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D002585:Cesarean Section / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D008278:Magnesium Sulfate / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D008278:Magnesium Sulfate; D002045:Bupivacaine
keywords: Anesthesia; Cesarean delivery; Magnesium sulfate; Spinal