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

Abstract

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 increased airway resistance was unevenly distributed. Constantine and associates (2) confirmed the increased 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 industrial conditions. She also commented on the considerable individual variation in response.The first part of the present study had two main objectives, the first of which was to determine the extent to which these inhaled materials altered the distribution of alveolar ventilation and to observe the effects this had upon respiratory gas exchange in the lungs. Of at least equal importance was the possibility that the experiments might reveal something of how the distribution of alveolar perfusion responds to an acute alteration in the distribution of alveolar ventilation, and this has influenced the design of the experiments.During these experiments the possibility arose that the observed effects might result from the associated moderate hyperventilation. A preliminary observation lent support to the idea that hyperventilation was followed by an increase in

Effect of bronchoconstrictor aerosols on the alveolar plateau of the single breath O2 test

“…Previous studies (Raine and Bishop, 1964;Norris and Bishop, 1966) showed an increase in the slope of the nitrogen plateau after carbachol and calcium carbonate dust in normal subjects, 'reactors', and patients with chronic bronchitis and bronchial asthma. However, only the mean value of the N2 gradient was reported.…”

Lung Function in Provoked Asthma: Responses to Inhaled Urea, Methacholine and Isoprenaline

“…Following the administration of a variety of bronchoactive agents, changes have been studied in ventilation (Colldahl, Holmgren, Pegelow & Svanborg, 1964;Stanescu, Teculescu, Pacararu & Popa, 1968), mechanical function (McIlroy & Marshall, 1956;Constantine, Dautrebande, Kaltrieder, Lovejoy, Morrow & Perkins, 1959; Dautrebande, Lovejoy & Constantine, 1960;Lovejoy, Constantine, Flatley, Kaltrieder & Dautrebande, 1961 ;Dubois & Dautrebande, 1958;Bouhuys, Hunt, Kim & Zapletal, 1969;Cade, Woolcock, Rebuck & Pain, 1971), ventilationblood-flow relationships (Raine & Bishop, 1964;Norris & Bishop, 1966) and gas transfer (Bouhuys, Georg, Jonsson, Lundin & Lindell, 1960;Stanescu & Teculescu, 1969).…”