Home nebulisers. Comparative study of lung deposition by different models

Home nebulisers are extensively used in the ambulatory treatment of chronic chest conditions. This study compares the intrapulmonary deposition of aerosol generated by 6 different models of electrical home nebuliser in healthy male volunteers. Deposition was quantified by measurement of the radio-activity over the right lung during nebulisation of 3 ml normal saline containing 2 mCi of technetium-99m pertechnetate. The 3 cheaper nebulisers studied (Simba, New Constellation and Ariette) take considerably longer to nebulise the same volume compared with the 3 more expensive nebulisers (Eolo, Pharmoneb and Pari) (> 20 minutes compared with < 5 minutes). With one exception, in every comparison between two models, intrapulmonary deposition at 3 minutes was significantly greater for the more expensive nebuliser. Mean deposition with the cheapest model was only one-fifteenth of the mean for the most expensive model. Large variations between different individuals on the same model were observed (up to 6-fold). Factors accounting for the inter-individual variation in deposition are considered and the correct method of use of nebulisers is emphasised. Multiple regression of forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) and height versus deposition with very similar nebulisers in 12 volunteers shows that these parameters can account for 69% of the inter-individual variation observed (r = 0.83). The clinical application of the findings is considered.