Lung deposition of aerosol - A comparison of different spacers

Aims - To investigate (1) aerosol lung deposition obtained from two small volume conventional spacers (Babyhaler and Aerochamber) and a home made spacer (modified 500 ml plastic cold drink bottle); (2) the effect of using a face mask or mouthpiece; and (3) the relation between age and pulmonary deposition. Methods - Lung deposition of aerosolised technetium-99m DTPA inhaled via spacer was measured in 40 children aged 3-7 years with stable asthma. Each patient performed sequential randomly assigned inhalations using two spacers. Three studies were performed: Babyhaler compared to Aerochamber (with facemasks); Babyhaler with facemask compared to Babyhaler with mouthpiece; and Babyhaler with mouthpiece compared to a 500 ml bottle. Results - Median lung aerosol deposition from a Babyhaler and Aerochamber with masks were similar (25% υ 21%, p = 0.9). Aerosol lung deposition from a Babyhaler with mask compared to a Babyhaler with mouthpiece was equivalent (26% υ 26%, p = 0.5). Lung deposition was higher from a 500 ml bottle compared to a Babyhaler in both young (25% υ 12.5%, p=0.005) and older children (42% υ 22.5%, p = 0.003). A notable reduction in pulmonary deposition occurred at 50 months of age. Conclusion - A Babyhaler or Aerochamber produce equivalent lung deposition of aerosol. There is no difference in lung deposition when a mask or mouthpiece is used. A modified 500 ml plastic bottle produces greater pulmonary aerosol deposition than a conventional small volume spacer.