Output characteristics of DeVilbiss No. 40 hand-held jet nebulizers

quantifying airway responsiveness ln large populatlons using pharma-cological agents. We examined the aerosol cha racteristics of five nebullzers. Within each device, the aerosol output and droplet size were r easonably stable over a wide range or bulb pressures, although there were considerable differences In output cbaracterlstlcs between nebullzers. Tbe droplet size was very large compared to conventional aerosol delivery systems, with a mass median diameter greater than 10 Jlm for three of the rtve devices. Between 28-50 % of the output was In particles sufficiently small for airway deposition (<6.2 Jlm). A more vigorous compression of the bulb caused 11 small increase output and a reduction in droplet size, resulting In a much bigger variation In the output or the respirable aerosol (<6.2 Jlm) with changes ln bulb pressure. The loss due to evaporation was about 3.5%, causing 11 similar rise In the osmolality of the nebullzer solution. In view or the variable nebullzer output and the marked between-operator variation In bulb pressure, tbe charac-teristics of Individual DeVllblss No. 40 nebullzers should be evaluated by individual operators before use In clinical practice or research