title: Combined spinal epidural vs epidural labour analgesia: does initial intrathecal analgesia reduce the subsequent minimum local analgesic concentration of epidural bupivacaine?
abstract: Labour analgesia initiated using a combined spinal-epidural (CSE) technique may reduce subsequent epidural bupivacaine requirements compared with an epidural-only technique. We compared the minimum local analgesic concentrations (MLAC) of epidural bupivacaine following initial intrathecal or epidural injection. In a prospective, double-blind study, 115 women requesting epidural analgesia were randomly assigned to receive either an epidural with bupivacaine 20 mg and fentanyl 40 μg or a CSE with intrathecal bupivacaine 2.5 mg and fentanyl 5 μg. Analgesia was assessed using a visual analogue pain score. When further analgesia was requested, bupivacaine 20 ml was given, and the concentration was determined using the technique of up-down sequential allocation. The MLAC of bupivacaine in the epidural group was 0.032% wt/vol (95% CI 0.020-0.044) compared with 0.047% wt/vol (95% CI 0.042-0.052) in the CSE group. Bupivacaine requirements for the second injection were increased following intrathecal analgesia by a factor of 1.45 (p = 0.026) compared with epidural analgesia.
authors.affiliation: Research Fellow in Obstetric Anaesthesia, University College London Hospitals NHS Trust, London, UK.
authors.forename: N P
authors.initials: NP
authors.lastname: Patel
authors.forename: S L
authors.initials: SL
authors.lastname: Armstrong
authors.forename: R
authors.initials: R
authors.lastname: Fernando
authors.forename: M O
authors.initials: MO
authors.lastname: Columb
authors.forename: J K
authors.initials: JK
authors.lastname: Bray
authors.forename: V
authors.initials: V
authors.lastname: Sodhi
authors.forename: G R
authors.initials: GR
authors.lastname: Lyons
mesh_terms: D000328:Adult; D015360:Analgesia, Epidural / Q000009:adverse effects / Q000379:methods*; D016362:Analgesia, Obstetrical / Q000009:adverse effects / Q000379:methods*; D000701:Analgesics, Opioid; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000009:adverse effects; D001794:Blood Pressure / Q000187:drug effects; D002045:Bupivacaine / Q000008:administration & dosage* / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004809:Ephedrine / Q000627:therapeutic use; D005260:Female; D005283:Fentanyl; D005500:Follow-Up Studies; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007278:Injections, Spinal; D009068:Movement / Q000187:drug effects; D010147:Pain Measurement; D011247:Pregnancy; D012044:Regression Analysis; D017211:Treatment Failure; D014662:Vasoconstrictor Agents / Q000627:therapeutic use
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D014662:Vasoconstrictor Agents; D004809:Ephedrine; D005283:Fentanyl; D002045:Bupivacaine