title: Success of spinal and epidural labor analgesia: comparison of loss of resistance technique using air versus saline in combined spinal-epidural labor analgesia technique.
abstract: BACKGROUND
  Comparison of air versus saline for loss of resistance technique (LORT) in combined spinal epidural labor analgesia (CSE) has not been evaluated, and neither has the relation between CSE characteristics (the presence/absence of initial spontaneous clear fluid return or upon aspiration) and spinal/epidural analgesia outcomes. The authors hypothesized that there is no difference in the spinal analgesia success or epidural catheter efficacy between using air versus saline LORT for CSE.
  
  
  METHODS
  A total of 360 patients were randomized to air or saline LORT for CSE. Primary outcome was spinal analgesia success as defined by verbal pain score of no more than 3 at 15 min after spinal dose administration. Secondary outcomes were CSE characteristics, catheter replacement, and average hourly epidural drug consumption.
  
  
  RESULTS
  Results from 345 patients were analyzed. Spinal analgesia success, epidural catheter replacement, and drug consumption were not different between using air or saline LORT and were also independent of the presence/absence of fluid return on aspiration if initial spontaneous fluid returned to the spinal needle. However, epidural catheters inserted in absence of initial fluid return had a significantly higher catheter replacement rate (28.6%) than the 4.1% among those with initial fluid return (P < 0.03).
  
  
  CONCLUSIONS
  Spinal analgesia success rate and epidural efficacy are independent of whether air or saline is used for LORT during CSE. Practice of aspiration for fluid after observing initial fluid return may be unnecessary because this practice does not alter spinal/epidural analgesia outcomes. However, epidural catheters inserted with the absence of initial fluid returned to spinal needle may pose a high failure risk.
authors.affiliation: Department of Anesthesiology, University of Vermont/Fletcher Allen Health Care, Burlington, Vermont 05401, USA. ccpgood@yahoo.com
authors.forename: Lydia S
authors.initials: LS
authors.lastname: Grondin
authors.forename: Kenneth
authors.initials: K
authors.lastname: Nelson
authors.forename: Vernon
authors.initials: V
authors.lastname: Ross
authors.forename: Orlando
authors.initials: O
authors.lastname: Aponte
authors.forename: Sherman
authors.initials: S
authors.lastname: Lee
authors.forename: Peter H
authors.initials: PH
authors.lastname: Pan
mesh_terms: D000328:Adult; D000388:Air; D015360:Analgesia, Epidural / Q000379:methods*; D016362:Analgesia, Obstetrical / Q000379:methods*; D005260:Female; D006801:Humans; D048949:Labor Pain / Q000188:drug therapy* / Q000503:physiopathology; D007743:Labor, Obstetric / Q000187:drug effects / Q000502:physiology; D011247:Pregnancy; D012965:Sodium Chloride / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D012965:Sodium Chloride