title: Intrathecal sufentanil decreases the median effective dose (ED50) of intrathecal hyperbaric ropivacaine for caesarean delivery.
abstract: BACKGROUND
  The addition of opioid to local anaesthetics has become a well-accepted practice of spinal anaesthesia for caesarean delivery. Successful caesarean delivery anaesthesia has been reported with the use of a low dose of intrathecal hyperbaric ropivacaine coadministered with sufentanil. This prospective, double-blinded study determined the median effective dose (ED50) of intrathecal hyperbaric ropivacaine with and without sufentanil for caesarean delivery, to quantify the sparing effect of sufentanil on the ED50 of intrathecal hyperbaric ropivacaine.
  
  
  METHODS
  Sixty-four parturients undergoing elective caesarean delivery with combined spinal-epidural anaesthesia were randomized into two groups: Group R (ropivacaine) and Group RS (ropivacaine plus sufentanil 5 microg). The initial dose of ropivacaine was 13 mg in Group R and 10 mg in Group RS. The effective dose was defined as a T(6) level attained within 10 min and no supplemental epidural anaesthetic required during surgery. Effective or ineffective responses determined, respectively, a 0.3 mg decrease or increase of the dose of ropivacaine for the next patient using an up-down sequential allocation.
  
  
  RESULTS
  The ED50 of intrathecal ropivacaine was 11.2 mg [confidence interval (CI) 95%: 11.0-11.6] in Group R vs. 8.1 mg (CI 95%: 7.8-8.3) in Group RS. Motor block was markedly more intense in Group R than in Group RS, and the incidence of shivering was lower in Group RS than in Group R. There were no differences in the onset time of sensory block or motor block, in the incidence of hypotension, nausea and vomiting.
  
  
  CONCLUSIONS
  Intrathecal sufentanil 5 microg produced a 28% reduction of ED50 of intrathecal hyperbaric ropivacaine for caesarean delivery.
authors: Department of Anaesthesia, Women's Hospital, School of Medicine, Zhejiang University, Zhejiang 310006, China.
authors: X
authors: X
authors: Chen
authors: X
authors: X
authors: Qian
authors: F
authors: F
authors: Fu
authors: H
authors: H
authors: Lu
authors: B
authors: B
authors: Bein
mesh_terms: D000759:Adjuvants, Anesthesia / Q000008:administration & dosage; D000328:Adult; D000577:Amides / Q000008:administration & dosage; D000767:Anesthesia, Epidural; D000773:Anesthesia, Obstetrical; D000775:Anesthesia, Spinal; D000779:Anesthetics, Local / Q000008:administration & dosage; D002585:Cesarean Section; D004311:Double-Blind Method; D004562:Electrocardiography; D023381:Endpoint Determination; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D009046:Motor Neurons / Q000187:drug effects; D009407:Nerve Block; D010100:Oxygen / Q000097:blood; D010147:Pain Measurement; D011247:Pregnancy; D011446:Prospective Studies; D000077212:Ropivacaine; D011984:Sensory Receptor Cells / Q000187:drug effects; D017409:Sufentanil / Q000008:administration & dosage
chemical_list: D000759:Adjuvants, Anesthesia; D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine; D017409:Sufentanil; D010100:Oxygen