Thorax 1984;39:935-941 Improvement of pressurised aerosol deposition with Nebuhaler

ABSTRACT The effect on aerosol deposition from a pressurised metered dose inhaler of a 750 cm3 spacer device with a one way inhalation valve (Nebuhaler, Astra Pharmaceuticals) was assessed by means of an in vivo radiotracer technique. Nine patients with obstructive lung disease took part in the study. The pattern of deposition associated with use of a metered dose inhaler alone was compared with that achieved with the spacer used both for inhalation of single puffs of aerosol and for inhalation of four puffs actuated in rapid succession and then inhaled simultane-ously. On each occasion there was a delay of 1 s between aerosol release and inhalation, simulat-ing poor inhaler technique. With the metered dose inhaler alone, a mean (SEM) 8-7 (1-8) % of the dose reached the lungs and 80*9 (1 9) % was deposited in the oropharynx. With single puffs from the spacer 20-9 (1.6) % of the dose (p < 0.01) reached the lungs, only 16-5 (2.3) % (p < 0.01) was deposited in the oropharynx, and 55-8 (3 1) % was retained within the spacer itself. With four puffs from the spacer 15-2 (1.5) % reached the lungs (p = 0-02 compared with the metered dose inhaler alone, p < 0-01 compared with single puffs from the spacer), 11-4 (1.2)% was deposited in the oropharynx, and 67*5 (1.8) % in the device itself. It is concluded that the spacer device gives lung deposition of metered dose aerosols comparable to or greater than