Effect of lung function and mode of inhalation on penetration of aerosol into the human lung.

The method using radioactive tracer particles has been applied to study the effect of the mode of inhalation of aerosols on the depth of deposition in the lungs of 50 patients with airways obstruction. The findings show that the penetration of particles is directly related to: (1) volume inspired per breath (VI); (2) forced expiratory volume in one second (FEV1); and inversely related to (3) flow rate during inhalation (V). In mathematical terms, alveolar deposition (%) = 40-3 (VI)+10-98 (FEV1)--0-75 (V)+40-4; for this regression F = 4-41 and P less than 0-01.