[Inhalation chambers]

Since the last 30 years metered-dose pressurised aerosols have largely contributed to the treatment of asthma with inhaled beta-2 stimulants and corticosteroids. Two problems, however, are associated with these aerosols: (1) small amounts of active substance are deposited in the lungs and larger amounts in the mouth and pharynx; (2) aerosols are uneasy to use because of lack of coordination between actuation and inhalation and absence of apnoea at the end of inspiration. An elegant solution of these problems is the inhalation chamber: a reservoir inserted between the patient's mouth and the aerosol, which increases the lung deposition, reduces the ENT deposition and makes coordination unnecessary. The inhalation chamber is primarily indicated for patients with poor coordination. When beta-2 stimulants are inhaled the therapeutic benefit can be measured by a gain of efficacy in poor coordinators. When corticosteroids are inhaled the benefit is measured by a better local tolerance and, to some extent, by a gain in therapeutic effectiveness; the inhalation chamber here is indicated for patients with ENT complications (e.g. candidiasis, dysphonia) or for the most severe cases requiring high-dose therapy. The introduction of inhalation chamber must be regarded as an improvement in the management of asthma, taking into account the potential risk of poor compliance, and in such cases the development of powder inhalers may be envisaged.