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Delivery of a β2 agonist by metered dose inhaler with a bottle spacer was equivalent to delivery by conventional spacer in young children with acute lower airway obstruction
  1. Roberta Heale, RN(EC), MN
  1. Laurentian University School of Nursing,
    Sudbury, Ontario, Canada

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Q In young children with acute lower airway obstruction, is response to bronchodilator treatment given using a metered dose inhaler (MDI) with a bottle spacer equivalent to that given using a conventional spacer?


Embedded ImageDesign:

randomised controlled equivalence trial.

Embedded ImageAllocation:


Embedded ImageBlinding:

blinded ({healthcare providers, data collectors},* and clinical outcome assessors).

Embedded ImageFollow up period:

after completion of 3 bronchodilator treatments.

Embedded ImageSetting:

a children’s hospital in Cape Town, South Africa.

Embedded ImagePatients:

400 children aged 2 months to 5 years (median age 12 mo, 39% boys) who presented with clinical signs of acute lower airway obstruction (expiratory wheeze on auscultation or hyperinflation of the chest) and had cough or difficulty breathing within the previous 5 days. Exclusion criteria were bronchodilator use in the previous 4 hours, underlying cardiac or chronic pulmonary disease (other than asthma), stridor, or daily oral corticosteroid treatment for >2 days before presentation.

Embedded ImageIntervention:

salbutamol, 500 μg, 5 puffs given at 1 puff every 10 seconds from an MDI using a modified 500 ml plastic bottle spacer, where the end of the bottle was held in the mouth simulating a mouthpiece (n = 200), or using a conventional spacer (Aerochamber, Trudell Medical, London, Ontario) (n = 200). A facemask was used for children <3 years of age. Children were reassessed 15 minutes after bronchodilator administration; if no improvement, a repeat inhalation was given, and if no improvement after 15 minutes, a third inhalation was given, and condition was reassessed after 15 minutes. If further treatment was required, children received nebulised salbutamol, 5 mg in 2.5 ml normal saline, using a jet nebuliser, and were reassessed after 15 minutes.

Embedded ImageOutcomes:

admission to hospital (criteria for admission: room air oxygen saturation <92% after 3 bronchodilator treatments, persistent subcostal retractions, cyanosis, or social circumstances precluding safe home care of the acute episode). Equivalence was defined as ⩽10% absolute increase in hospital admission with the bottle spacer. Secondary outcomes included change in Asthma Severity Scale clinical score, change in oximetry, number of bronchodilator treatments, and need for systemic corticosteroids.

Embedded ImagePatient follow up:

100% (intention to treat analysis).


60 children (15%) were admitted to hospital. 15% of children in each of the bottle spacer and conventional spacer groups were admitted to hospital. The upper limit of the 90% confidence interval (ie, the largest benefit that could reasonably be expected with a conventional spacer) was 5.9%, and so the criteria for equivalence (<10% difference between groups) was met. Assuming this maximal difference of 5.9% (as above), 1 additional child would be admitted to hospital for every 17 children treated with a bottle spacer. The groups did not differ any of the secondary outcomes.


In young children with acute lower airway obstruction, β2 agonist administration using a metered dose inhaler with a bottle spacer was equivalent to administration using a metered dose inhaler with a conventional spacer for hospital admissions.


Asthma is an important health concern for young children. The number of children with asthma is increasing,1 and most hospital admissions for asthma occur in children <4 years of age.2 Thus, the promotion of effective strategies for acute exacerbations and ongoing management of childhood asthma should be a priority.

Inhalers are easier for children to use and more effective if used with a spacer, although evidence suggests that the effectiveness of inhalers is reduced with ill fitting spacers.3 In addition, parents sometimes struggle with the cost of conventional spacers, the inconvenience of replacing lost or old spacers, and the potentially harmful effects of bacterial contamination of spacers.4

Zar et al showed that “home-made” bottle spacers were as effective as conventional spacers used with MDIs for delivery of β2 agonists. Bottle spacers may offer advantages to healthcare practitioners and to parents, who could be taught to clean, construct, and prime the plastic bottle spacers. Use of plastic bottles as spacers may increase accessibility to this device and offer an easy replacement for lost, forgotten, or older conventional spacers. The use of a bottle spacer would be particularly helpful in areas where accessibility to commercial products is limited. A disadvantage is that the preparation of the bottle spacer is complex, requiring {melting a hole in the bottom of the bottle},* cleaning, and priming of the bottle with 10 puffs. The study report by Zar et al only indicated bottle size. It is not known whether variables related to differences in plastic, shape, colour, or other bottle characteristics would alter the effectiveness of the spacer.

The ability to offer simple, cost effective alternatives made from commonly available materials, such as a bottle spacer, may increase compliance with the use of spacers and, ultimately, benefit children with asthma.


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  • * Information provided by author.

  • For correspondence: Professor H Zar, Red Cross War Memorial Children’s Hospital, University of Cape Town, Cape Town, South Africa. hzar{at}

  • Sources of funding: World Health Organization and Allergy Society of South Africa.

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