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Heliox for croup in children

  • Review
  • Intervention




Croup, a common acute clinical syndrome in children up to the age of six, is thought to be triggered by a viral infection, and is characterised by a varying degree of respiratory distress due to upper airway inflammation and oedema of the subglottic mucosa. Corticosteroids, now part of the standard treatment for croup, improve symptoms but it takes time for their full effect to be achieved. Meanwhile, the child remains at risk of deterioration and developing respiratory failure necessitating emergency intubation and ventilation. Helium-oxygen (heliox) inhalation has been successful in the treatment of upper airway obstruction. Anecdotal evidence suggests that heliox relieves respiratory distress in children, but it remains unclear whether there is robust evidence to support the implementation of heliox for croup into clinical practice.


To examine the effect of heliox on relieving symptoms and distress, determined by a croup score (a tool for measuring the severity of croup) or clinical assessment variables, through comparisons with placebo or active treatment(s) in children with croup.

Search methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, issue 2) which contains the Acute Respiratory Infections (ARI) Group's Specialised Register; MEDLINE (1950 to June week 3 2009); EMBASE (1974 to 2009 week 25) and CINAHL (1982 to June 2009).

Selection criteria

Randomised controlled trials (RCTs) and quasi-RCTs comparing the effect of helium-oxygen mixtures with placebo or any active treatment in children with croup.

Data collection and analysis

Both authors independently identified and assessed citations for relevance. We assessed included trials for risk of bias using allocation concealment, blinding of intervention, completeness of outcome data, selective outcome reporting and other potential source of bias. We calculated mean differences for continuous data. We presented data not suitable for statistical analysis as descriptive data.

Main results

Two eligible RCTs were included (22 intervention, 22 controls). Neither trial compared heliox inhalation with placebo. One study compared heliox with 30% humidified oxygen whilst the other compared it to 100% oxygen with additional racaemic epinephrine nebulisation. There was no significant difference in change of croup score between intervention and control groups.

Authors' conclusions

At present there is a lack of evidence to establish the effect of heliox inhalation in the treatment of croup in children. A methodologically well-designed and adequately powered RCT is needed to assess whether there is a role for heliox therapy in the management of children with croup.








我們檢索了Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009年,第2期),其中包含急性呼吸道感染(ARI)Group's Specialised Register; MEDLINE(1950年至2009年6月第3週),EMBASE(1974年2009年第25週)和CINAHL(1982年至2009年6月)。




兩位作者獨立地識別及評估引用文獻的相關性。對於納入的試驗,我們評估偏差的風險,項目包含分組是否隱匿、介入時是否blinding、結果資料是否完整、是否選擇性的結果報告和其他潛在偏差的來源。針對連續性數據,我們計算平均差異 (mean difference) 。不適合統計分析的資料則以描述性資料呈現。







此翻譯計畫由臺灣國家衛生研究院 (National Health Research Institutes, Taiwan) 統籌。



Plain language summary

Helium-oxygen (heliox) treatment for croup in children

Croup is an acute illness commonly seen in children up to the age of six years. It causes upper airway obstruction resulting in varying degree of respiratory distress. Helium-oxygen (heliox), a gas with lower density than air or oxygen, is thought to improve gas flow and thus reduce flow resistance in the pathologically narrowed upper airway. This is believed to improve clinical symptoms of distress. By undertaking this review we found two trials assessing the effect of heliox on reducing symptom severity in children with croup. Neither study found a significant improvement with heliox treatment. However, both trials were small (total of 44 participants) and had a number of methodological limitations. Due to the lack of quality trials there is currently insufficient evidence to conclude whether heliox is effective in relieving symptoms in croup. A methodologically well-designed trial with a sufficient number of participants is needed to assess whether there is a role for heliox therapy in children with croup.