title: Use of helium-oxygen mixtures in the treatment of croup: a systematic review.
abstract: OBJECTIVE
  To determine the effect of helium-oxygen inhalation on relieving symptoms and distress in children with croup as measured by the croup score, and to identify areas of uncertainty for future research.
  
  
  METHODS
  Systematic review of prospective randomised and non-randomised controlled trials of children with the clinical diagnosis of croup, comparing the effect of helium-oxygen mixtures with placebo or any active treatment. Outcome measures were change in croup score, physiological parameters, hospital admission rates, need for intubation and adverse events. All records as identified by a systematic search strategy were assessed independently by two reviewers.
  
  
  RESULTS
  Two trials were identified for inclusion assessing the effect of helium-oxygen inhalation in children with croup in an emergency department. In one trial the control group received humidified oxygen and in the other nebulised epinephrine. An improvement in the mean croup score over time was seen in the control and intervention groups of both trials, with no significant difference between the groups. Significant methodological and clinical heterogeneity in the design of the trials precluded a meaningful meta-analysis.
  
  
  CONCLUSIONS
  At present there is no evidence to support the use of helium-oxygen therapy in children with croup. Methodologically well-designed and adequately powered randomised controlled trials are needed to determine whether helium-oxygen inhalation as part of the initial treatment in croup alters outcome.
authors: Emergency Department Academic Unit, Leicester Royal Infirmary, Leicester LE1 5WW, UK. cv28@le.ac.uk
authors: C
authors: C
authors: Vorwerk
authors: T J
authors: TJ
authors: Coats
mesh_terms: D000280:Administration, Inhalation; D002675:Child, Preschool; D002986:Clinical Trials as Topic; D003440:Croup / Q000628:therapy*; D004630:Emergencies; D004638:Emergency Treatment; D006371:Helium / Q000627:therapeutic use*; D006801:Humans; D007223:Infant; D010100:Oxygen / Q000627:therapeutic use*; D011446:Prospective Studies; D016896:Treatment Outcome
chemical_list: D006371:Helium; C038949:heliox; D010100:Oxygen