THE EFFICACY OF ALTERNATIVE SPACER DEVICES FOR DELIVERY OF AEROSOL THERAPY TO CHILDREN WITH ASTHMA

Spacer devices are important aids for use with metered dose inhalers i n children with asthma. However, expense and unavailability of commerc ially produced spacers in developing countries have limited their use. Home-made spacers in the form of cups or bottles are widely used desp ite a lack of data confirming their efficacy. We investigated the rela tive efficacy of three spacers (a commercially available spacer, a mod ified 500-ml cold drink bottle and a polystyrene cup) for delivery of aerosolized drugs to asthmatic children older than 5 years. We also in vestigated the effect of leaks in the delivery system by comparing del ivery via a sealed and an unsealed cold drink bottle. Lung deposition of aerosolized Tc-99m DTPA inhaled via spacer was measured in 30 patie nts. The median aerosol deposition in the lungs was significantly grea ter for the conventional spacer than for the cup (31.5% vs 9.5%; Z = - 2.8, p = 0.005). Median aerosol deposition for the conventional spacer and sealed bottle were equivalent (40.5% vs 44%). Aerosol deposition from the sealed and unsealed bottle was significantly different (43.5% vs 24%; Z = -2.54, p = 0.01); however, the unsealed bottle was more e fficient than the cup. We conclude that a modified 500-ml cold drink b ottle is an efficient spacer. Leaks in this system are a major factor affecting the amount of drug deposited. The modified polystyrene cup i s not an efficient spacer, delivering between a third and a fifth of t he dose that other spacers were capable of delivering.