title: The efficacy and effect of opioid analgesia in undifferentiated abdominal pain in children: a review of four studies.
abstract: BACKGROUND
  The question of whether opioid analgesia should be given in patients with undifferentiated acute abdominal pain has been characterized by concerns about its efficacy and that signs used to determine accurate diagnosis may be masked by the drug. The objective of this review is to critically analyze pertinent pediatric randomized controlled studies considering this issue.
  
  
  METHODS
  A comprehensive literature search was conducted via Medline in October 2007, using the terms 'abdominal pain', 'physical examination', 'analgesics', 'opioid' and 'appendicitis'. Other articles were identified using the bibliographies of papers found through Medline; alternate databases were searched but did not reveal additional studies.
  
  
  RESULTS
  A total of four trials were identified, and their validity and applicability were reviewed. In all studies, randomization to the analgesia group was associated with significant reduction in pain; one study showing no greater effect with opioid than placebo. All studies used a 10 cm Visual Analogue Scale to assess pain. All studies were only sufficiently powered to consider the primary outcome of opioid efficacy in abdominal pain vs placebo rather than diagnostic accuracy, although they all reported on diagnostic accuracy. Meta-analysis of results for efficacy and accuracy was not possible due to the heterogeneity of study populations.
  
  
  CONCLUSIONS
  A large, probably multi-centred trial is needed to answer with sufficient power the question of whether opioid analgesia impairs diagnostic accuracy in children with undifferentiated acute abdominal pain.
authors.affiliation: Emergency Department, Royal Children's Hospital, Murdoch Children's Research Institute, Parkville, Vic. 3055, Australia. lisa.sharwoodl@gmail.com
authors.forename: Lisa N
authors.initials: LN
authors.lastname: Sharwood
authors.forename: Franz E
authors.initials: FE
authors.lastname: Babl
mesh_terms: D000006:Abdomen, Acute / Q000175:diagnosis / Q000188:drug therapy; D015746:Abdominal Pain / Q000175:diagnosis / Q000188:drug therapy*; D000293:Adolescent; D000701:Analgesics, Opioid / Q000627:therapeutic use*; D001064:Appendicitis / Q000175:diagnosis; D002648:Child; D002675:Child, Preschool; D004632:Emergency Medical Services / Q000379:methods; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome
chemical_list: D000701:Analgesics, Opioid