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Drug delivery in asthma: a comparison of spacers with a jet nebuliser
P G Gibson1, J H Wlodarczyk, T Borgas
1Respiratory Medicine Unit, John Hunter Hospital, Newcastle, NSW.
Background:
Although spacer devices are frequently used for aerosol therapy in asthma, the commonly used spacers have undergone little controlled evaluation, and their relation to nebuliser therapy is unclear.
Aims:
The aims of this study were to compare three delivery methods (Breath-A-Tech spacer, Volumatic spacer and jet nebuliser) for the administration of salbutamol to reverse acute histamine induced airway narrowing in asthma (Study 1); and to assess asthma control during two weeks use of inhaled therapy via Volumatic or Breath-A-Tech spacer (Study 2).
Methods:
A randomised double-blind cross-over comparison was conducted. In Study 1, 27 adults with stable asthma who were currently using pressurised metered dose inhaler therapy attended for three study days. On each study day subjects inhaled doubling doses of histamine and were randomised to receive: (a) salbutamol 200 micrograms via Breath-A-Tech spacer and placebo 200 micrograms via Volumatic spacer; (b) placebo two puffs via Breath-A-Tech spacer and salbutamol 200 micrograms via Volumatic spacer; or (c) salbutamol 1 mg in 2 mL saline via jet nebuliser. FEV1 and FEF 25-75% were measured at two minute intervals for 20 minutes. In Study 2, subjects were randomised to use regular asthma medication by Volumatic or Breath-A-Tech spacers and recorded symptoms and peak expiratory flow (PEF) in a daily diary.
Results:
Lung function improved from a baseline FEV1 of 51% predicted to 72% after salbutamol inhalation from each of the delivery systems. The spacers and nebulisers produced the same maximum improvement in FEV1, however, lung function improved more rapidly when salbutamol was delivered by spacer. There was no difference in asthma control comparing inhaler use via Breath-A-Tech with Volumatic spacer over two weeks use. Subject preference favoured the Breath-A-Tech spacer (72% vs 4%).
Conclusions:
The Volumatic and Breath-A-Tech spacer devices are effective delivery systems in asthma and may offer a more rapid response than jet nebulisation at a lower cost.