Influence of acute isocapnic hypoxia on bronchial calibre and "expiratory reserve" volume in dogs.
The effects of hypoxia on bronchial calibre were investigated in anaesthetized dogs using a computer-aided forced airflow oscillation technique which derived specific lower airways conductance (sGlaw) and "expiratory reserve volume" (ERV). Measurements were made with inspired oxygen concentrations varying from 40% to 10%. sGlaw tended to be slightly reduced (indicating bronchoconstriction) by decreasing the oxygen concentration from 40% to 15%, these changes being statistically significant after the administration of atropine. ERV was unaffected by changes in oxygen concentration from 40% to 15%, but was significantly reduced during ventilation with 10% oxygen. This effect was reversed by re-oxygenation and was not abolished by prior administration of atropine. It was concluded that both bronchoconstriction and changes in lung volume may be responsible for changes in airway resistance during hypoxia.
D000403:Airway Resistance / Q000187:drug effects; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001980:Bronchi / Q000187:drug effects; D002245:Carbon Dioxide / Q000502:physiology; D004285:Dogs; D005105:Expiratory Reserve Volume; D005260:Female; D005652:Functional Residual Capacity; D008176:Lung Volume Measurements; D008297:Male; D010100:Oxygen / Q000494:pharmacology* / Q000502:physiology; D012123:Pulmonary Ventilation / Q000187:drug effects
D002245:Carbon Dioxide; D001285:Atropine; D010100:Oxygen