title: Is combined spinal-epidural analgesia associated with more rapid cervical dilation in nulliparous patients when compared with conventional epidural analgesia?
abstract: BACKGROUND
  The combined spinal-epidural technique provides rapid onset of labor analgesia and, anecdotally, is associated with labors of shorter duration. Epidural analgesia, by contrast, has been suggested to prolong labor modestly. It is unclear, however, whether more rapid cervical dilation in patients who receive combined spinal-epidural analgesia is a physiologic effect of the technique or an artifact of patient selection. The authors hypothesized that anesthetic technique may influence the rate of cervical dilation, and we compared the effects of combined spinalepidural with those of epidural analgesia on the rate of cervical dilation.
  
  
  METHODS
  One hundred healthy nulliparous parturients in spontaneous labor with singleton, vertex, full-term fetuses were enrolled in a double-blinded manner when their cervical dilation was less than 5 cm. The patients were randomly assigned to receive analgesia via a standardized combined spinal-epidural (n = 50) or epidural (n = 50) technique. Data were collected on cervical dilation, pain, sensory level, and motor blockade.
  
  
  RESULTS
  When regional analgesia was induced in comparable groups at a mean of 3 cm cervical dilation, the mean initial cervical dilation rates were significantly faster in the combined spinal-epidural group (mean values, 2.1 +/- 2.1 cm/h vs. 1 +/- 1 cm/h; P = 0.0008). Five parturients in the combined spinal-epidural group had a very rapid (> 5 cm/h) rate of mean initial cervical dilation, compared with none of the women in the epidural group. Overall mean cervical dilation rates in patients who achieved full cervical dilation were 2.3 +/- 2.6 cm/h and 1.3 +/- 0.71 cm/h (P = 0.0154) in the combined spinal-epidural and epidural groups, respectively.
  
  
  CONCLUSIONS
  In healthy nulliparous parturients in early labor, combined spinal-epidural analgesia is associated with more rapid cervical dilation compared with epidural analgesia. Further study is needed to elicit the cause and overall effect of this difference.
authors.affiliation: Department of Anesthesiology, Perioperative and Pain Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA. lctsen@bics.bwh.harvard.edu
authors.forename: L C
authors.initials: LC
authors.lastname: Tsen
authors.forename: B
authors.initials: B
authors.lastname: Thue
authors.forename: S
authors.initials: S
authors.lastname: Datta
authors.forename: S
authors.initials: S
authors.lastname: Segal
mesh_terms: D000328:Adult; D015360:Analgesia, Epidural / Q000379:methods*; D016362:Analgesia, Obstetrical / Q000379:methods*; D000775:Anesthesia, Spinal / Q000379:methods; D002584:Cervix Uteri / Q000502:physiology*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D007743:Labor, Obstetric; D011247:Pregnancy