title: Effects of volume and concentration of lidocaine on epidural anaesthesia in pregnant females.
abstract: OBJECTIVE
  The effects of altering the concentration of a local anaesthetic on the development of epidural anaesthesia in pregnant females are unclear. We compared the anaesthetic effects of a constant dose of two different concentrations of epidural lidocaine for Caesarean section.
  
  
  METHODS
  After Institutional Review Board approval and informed consent, patients undergoing elective Caesarean section were randomized to receive either lidocaine 1% 30 mL (+epinephrine 5 microg mL(-1)) or lidocaine 2% 15 mL (+epinephrine 5 microg mL(-1)) (n = 20 each) for epidural anaesthesia at the L1-L2 interspace. The spread of the sensory block to pinprick and the degree of motor block (modified Bromage scale) were measured at 5, 10, 15, 20 and 30 min after injection.
  
  
  RESULTS
  No significant differences in the progression of analgesia and motor block were observed at any time between 1 and 2% lidocaine. The maximum cephalad spread was observed 30 min after injection; the median was at T4 (range T3-T5) and at T4 (range T3-T6) for lidocaine 1 and 2%, respectively.
  
  
  CONCLUSIONS
  The same doses but different volumes of lidocaine 1 and 2% produced comparable anaesthetic effects in pregnant females. The effects of epidural anaesthesia depend primarily on the total dose of the local anaesthetic.
authors.affiliation: Sapporo Medical University School of Medicine, Department of Anesthesiology, Japan. mnakaya@sapmed.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Nakayama
authors.forename: J
authors.initials: J
authors.lastname: Yamamoto
authors.forename: H
authors.initials: H
authors.lastname: Ichinose
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
authors.forename: N
authors.initials: N
authors.lastname: Kanaya
authors.forename: A
authors.initials: A
authors.lastname: Namiki
mesh_terms: D000328:Adult; D000767:Anesthesia, Epidural; D000773:Anesthesia, Obstetrical; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002585:Cesarean Section; D004311:Double-Blind Method; D004837:Epinephrine / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D008012:Lidocaine / Q000008:administration & dosage*; D009407:Nerve Block; D010147:Pain Measurement; D011247:Pregnancy
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine; D004837:Epinephrine