Acute Effects of Breathing Inert Dust Particles and of Carbachol Aerosol on the Mechanical Characteristics of the Lungs in Man. Changes in Response after Inhaling Sympathomimetic Aerosols1

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Abstract
On 5 human subjects without chronic respiratory disease, measurements of pulmonary compliance, total pulmonary resistance (esophageal pressure method), airway resistance, pulmonary tissue resistance, and thoracic gas volume (plethysmographic methods) and of lung volume subdivisions (spirometric determinations) were made during a control period before inhalation of small quantities of carbachol micromicellar aerosols and of fine, chemically inert dust particles consisting of calcium carbonate powder, coal dust, activated charcoal powder, aluminum powder and aerosolized India ink. After inhalation of these aerosols, the subjects usually showed a definite increase in airway resistance and pulmonary resistance and sometimes a slight decrease in lung compliance. Sympathomimetic aerosols were administered a few minutes afterwards and the same measurements repeated. They showed that the resistance had fallen below the initial control value and the compliance had increased to the normal control value or had sometimes increased beyond the control value. Following the administration of sympathomimetic aerosols, further inhalations of carbachol aerosol or of dust particles failed to raise the airway resistance above the initial control value and did not significantly reduce the lung compliance. Fifteen to 30 minutes after taking 6-25 breaths of carbachol aerosol or of dust-laden air, subdivisions of lung volume showed no significant change except in 1 of 5 subjects, who had a slight decrease in total lung capacity (mainly at the expense of the inspiratory capacity) on 1 occasion.