ACTION OF ISOPRENALINE ON MECHANICAL-PROPERTIES OF LUNGS AND AIRWAYS IN HEALTHY PEOPLE AND PATIENTS WITH OBSTRUCTIVE LUNG-DISEASES

  • 1 January 1976
    • journal article
    • research article
    • Vol. 12  (4) , 515-531
Abstract
Lung volumes, maximal expiratory flows, pulmonary resistance and static recoil pressure-volume curves were measured before and after inhalation of isoprenaline in 4 groups of subjects: healthy, patients with mild and severe chronic bronchitis and asthmatics. The observed changes were qualitatively similar in the 4 groups. Total lung capacity and dynamic compliance were not influenced, but there was an increase in vital capacity (not in healthy subjects and mild bronchitics), in FEV1 [forced expiratory vol in 1s] in maximal expiratory flows and a decrease in pulmonary resistance. The static recoil pressure-volume relationship was shifted to the left over its ascending part. The effect of isoprenaline tended to be larger in patients. Among the latter the increase of vital capacity was especially pronounced in the severe bronchitics; the maximal flows increased most in asthmatics. The influence of isoprenaline on maximal flows results from a bronchodilation, associated with an increased collapsibility of the central intrathoracic airways; the influence on vital capacity might reflect a delayed onset of small airway closure.