Helium-oxygen (heliox) treatment for croup in children

Vorwerk C, Coats T

Published Online:

February 17, 2010

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.

Abstract (click to read)

Background:

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.

Objectives:

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 strategy:

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.

This record should be cited as:

Vorwerk C, Coats T. Heliox for croup in children. Cochrane Database of Systematic Reviews 2010, Issue 2. Art. No.: CD006822. DOI: 10.1002/14651858.CD006822.pub2

Assessed as up to date:

June 26, 2009

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Primary Review Group:

Acute Respiratory Infections Group

Health topics:

Ear, nose, & throat > Larynx > Croup/epiglottitis

Infectious disease > Respiratory infections > Croup/epiglottitis

Lungs & airways > Respiratory infections > Croup/epiglottitis

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Helium-oxygen (heliox) treatment for croup in children

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