Alterations in Ventilation-Perfusion Relationships in the Lung after Breathing Inert Dust or Bronchoconstrictor Aerosols and after Short Periods of Voluntary Hyperventilation

The increase in airway resistance that follows the breathing of fine inert dust was first demonstrated by DuBois and Dautrebande (1), who also showed that an aerosol of carbachol had the same effect. The compliance of the lungs was reduced, which led these authors to conclude that the in- creased airway resistance was unevenly distributed. Constantine and associates (2) confirmed the in- creased airway resistance in similar experiments and also noted an increase in intrathoracic gas volume, which they attributed to trapping of gas. McDermott (3) found a significant increase in airway resistance after breathing similar dusts at concentrations almost certainly less than those used by the previous workers and more comparable to the concentrations encountered under certain in- dustrial conditions. She also commented on the considerable individual variation in response.