title: A randomized comparison of a five-minute versus fifteen-minute lockout interval for PCEA during labor.
abstract: BACKGROUND
  The best combination of bolus size and lockout interval for patient-controlled epidural analgesia (PCEA) is not known. This study compared a 5-min with a 15-min lockout interval.
  
  
  METHODS
  Parturients were randomly assigned to receive PCEA with either a 5-min or a 15-min interval. All had a 15-mL loading dose, continuous background infusion 6 mL/h of 0.125% bupivacaine plus fentanyl 2 mug/mL, PCEA bolus volume 5 mL, maximum hourly dose 26 mL. Visual analogue scores for pain, nausea and pruritus, sensory levels to ice, sacral analgesia, motor power, blood pressure and fetal heart rate were assessed pre-epidural and regularly thereafter until delivery. The numbers of boluses and attempts and patient satisfaction were recorded.
  
  
  RESULTS
  29 patients were assigned to the 5-min group and 31 to the 15-min group, but the 15-min group contained twice as many nulliparous women. Side-effect and complication rates did not differ between groups. VAS pain scores were reduced from a median of 79 in the 15-min group and 82 in the 5-min group to a median of zero 30 min after epidural insertion. Bolus/attempt ratio was 0.88 in the 5-min vs. 0.70 in the 15-min group. The numbers of requests for physician intervention were similar. No differences in pain scores, side-effects, drug use or patient satisfaction were demonstrated.
  
  
  CONCLUSIONS
  The 5-min lockout interval appears the more efficient and has been used safely in our practice for 15,000 parturients, although a larger study is required to confirm the relative efficacy, efficiency and safety of this regimen.
authors.affiliation: Department of Anesthesia and Perioperative Care, University of California San Francisco Moffitt Hospital, San Francisco, CA 94143, USA. stratman@anesthesia.ucsf.edu
authors.forename: G
authors.initials: G
authors.lastname: Stratmann
authors.forename: D R
authors.initials: DR
authors.lastname: Gambling
authors.forename: T
authors.initials: T
authors.lastname: Moeller-Bertram
authors.forename: J
authors.initials: J
authors.lastname: Stackpole
authors.forename: A F
authors.initials: AF
authors.lastname: Pue
authors.forename: J
authors.initials: J
authors.lastname: Berkowitz
mesh_terms: D000328:Adult; D015360:Analgesia, Epidural; D016362:Analgesia, Obstetrical; D016058:Analgesia, Patient-Controlled; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007231:Infant, Newborn; D009068:Movement / Q000187:drug effects; D010147:Pain Measurement; D020250:Postoperative Nausea and Vomiting / Q000453:epidemiology; D011247:Pregnancy