A COMPARATIVE STUDY OF CLINICAL AND FUNCTIONAL PATTERN IN EMPHYSEMATOUS PATIENTS WITH AND WITHOUT CHRONIC RESPIRATORY FAILURE

Abstract

Two groups of emphysematous patients, 8 with and 11 without chronic respiratory failure were compared. Loss of lung elasticity appeared to be the most prominent mechanical abnormality in the group with relatively normal arterial blood gases. Airway obstruction due to expiratory check-valving was less marked in this group than in the chronically hypercapnic group, in which it seemed to be the major difficulty, impairment of lung elasticity being a secondary feature. Differences were noted between the groups in other aspects of pulmonary function as well as in the clinical picture. The hypercapnic group was found to have lower mean values for vital and total lung capacity, diffusion, and resting minute ventilation. In addition, the typical chronic bronchitlc history preceding exertlonal dyspnea was more common in the group with normal blood gases. These differences suggested that qualitatively different disease processes were represented in the two groups of emphysematous patients. It was speculated that the underlying pathology in the hypercapnic type of emphysema might be centrilobular emphysema, as opposed to diffuse emphysema, in the group with normal blood gases. In addition, the findings suggested that the chief mechanism producing chronic hypercapnia in emphysema is an inability to compensate by hyperventilation for distributional defects, due to mechanical restriction of the respiratory bellows.