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BET 1: Efficacy of different techniques using a metered-dose inhaler with Spacer to relieve symptoms in children with acute asthma
  1. Ben Kerr Winter,
  2. Edward Carlton
  1. North Bristol NHS Trust, UK


A shortcut review was carried out to establish which inhaler with spacer technique provides the greatest improvement in symptoms in children with acute asthma. Four relevant papers were identified for inclusion using the reported search strategy. The author, date and country of publication; group studied; study type; relevant outcomes; results and study weaknesses of these papers are tabulated. It is concluded that a ‘tidal breathing’ technique, with a minimum of three breaths per inhaler activation, is likely equivalent in efficacy to a ‘single breath and hold technique’, and easier for a breathless child to perform.

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Clinical scenario

You see a child with an acute exacerbation of asthma and administer salbutamol via a pressurised metered-dose inhaler (pMDI) with a spacer. You give 10 puffs, with five tidal breaths per puff. The child’s father tells you that the school nurse had always recommended a ‘single breath and hold’ technique using a spacer. He asks you which technique is better.

Three-part question

In (children with acute asthma), which (pressurised metered-dose inhaler with spacer technique) will provide the greatest (improvement in symptoms)?

Search strategy

PubMed—date of searching 28 August 2019: (asthma OR paediatric asthma OR pediatric asthma OR childhood asthma OR wheeze) AND (spacer device technique OR chamber device technique) AND (deposition OR symptoms OR effect).

The Cochrane Library—date of searching 30 August 2019: MeSH descriptor: Inhalation Spacers [explode all trees] 41 records 0 relevancies, 1 duplicate.

Search outcome

Altogether 73 papers were found. All abstracts were screened, and four papers were relevant (see table 1).

Table 1

Relevant paper(s)


All studies were small (<100 participants), and none included children with acute exacerbations with asthma. Most compared a single deep inhalation and breath hold technique with a multiple breath technique (either tidal breathing or panting). Scintigraphy using radiolabelled drug demonstrated better lung deposition with a single breath and hold technique. However, studies that compared changes in respiratory physiology did not show any difference. Children with acute exacerbations of asthma are likely to struggle with the single breath and hold technique, as are younger children.

Clinical bottom line

Using a pMDI and spacer, a ‘tidal breathing’ technique is likely to be as effective at relieving symptoms as a ‘single breath and hold’ technique, and easier for a breathless child to perform. A minimum of three breaths should be taken per activation.



  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; internally peer reviewed.