title: Heliox therapy in bronchiolitis: phase III multicenter double-blind randomized controlled trial.
abstract: OBJECTIVE
  Supportive care remains the mainstay of therapy in bronchiolitis. Earlier studies suggest that helium-oxygen therapy may be beneficial, but evidence is limited. We aimed to compare efficacy of 2 treatment gases, Heliox and Airox (21% oxygen + 79% helium or nitrogen, respectively), on length of hospital treatment for bronchiolitis.
  
  
  METHODS
  This was a multicenter randomized blinded controlled trial of 319 bronchiolitic infant subjects randomly assigned to either gas; 281 subjects completed the study (140 Heliox, 141 Airox), whose data was analyzed. Treatment was delivered via facemask (nasal cannula, if the facemask intolerant) ± continuous positive airway pressure (CPAP). Severe bronchiolitics received CPAP from the start. Primary end point was length of treatment (LoT) required to alleviate hypoxia and respiratory distress. Secondary end-points were proportion of subjects needing CPAP; CPAP (LoT); and change in respiratory distress score.
  
  
  RESULTS
  Analysis by intention to treat (all subjects); median LoT (inter-quartile range, days): Heliox 1.90 (1.08-3.17), Airox 1.87 (1.11-3.34), P = .41. Facemask tolerant subgroup: Heliox 1.46 (0.85-1.95), Airox 2.01 (0.93-2.86), P = .03. Nasal cannula subgroup: Heliox 2.51 (1.21-4.32), Airox 2.81 (1.45-4.78), P = .53. Subgroup started on CPAP: Heliox 1.55 (1.38-2.01), Airox 2.26 (1.84-2.73), P = .02. Proportion of subjects needing CPAP: Heliox 17%, Airox 19%, O.R. 0.87 (0.47-1.60), P = .76. Heliox reduced respiratory distress score after 8 hours (mixed models estimate, -0.1298; P < .001). The effect was greater for facemask compared with nasal cannula (mixed models estimate, 0.093; P = .04).
  
  
  CONCLUSIONS
  Heliox therapy does not reduce LoT unless given via a tight-fitting facemask or CPAP. Nasal cannula heliox therapy is ineffective.
authors.affiliation: Department of Pediatrics, Wright Fleming Institute, Imperial College, London, United Kingdom.
authors.forename: Mina M
authors.initials: MM
authors.lastname: Chowdhury
authors.forename: Sheila A
authors.initials: SA
authors.lastname: McKenzie
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Pearson
authors.forename: Siobhan
authors.initials: S
authors.lastname: Carr
authors.forename: Caroline
authors.initials: C
authors.lastname: Pao
authors.forename: Arvind R
authors.initials: AR
authors.lastname: Shah
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Reus
authors.forename: Joseph
authors.initials: J
authors.lastname: Eliahoo
authors.forename: Fabiana
authors.initials: F
authors.lastname: Gordon
authors.forename: Hubert
authors.initials: H
authors.lastname: Bland
authors.forename: Parviz
authors.initials: P
authors.lastname: Habibi
mesh_terms: D000208:Acute Disease; D001988:Bronchiolitis / Q000628:therapy*; D045422:Continuous Positive Airway Pressure; D004311:Double-Blind Method; D005260:Female; D006371:Helium / Q000627:therapeutic use*; D006801:Humans; D007223:Infant; D057194:Intention to Treat Analysis; D008297:Male; D008397:Masks; D009584:Nitrogen / Q000627:therapeutic use*; D010100:Oxygen / Q000627:therapeutic use*; D010102:Oxygen Inhalation Therapy / Q000295:instrumentation / Q000379:methods; D012138:Respiratory Therapy / Q000295:instrumentation / Q000379:methods*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D006371:Helium; C038949:heliox; D009584:Nitrogen; D010100:Oxygen