Physiologic diagnosis of subclinical emphysema.

Abstract

The present study was designed to determine whether screening pulmonary function tests could establish a diagnosis of emphysema that was clinically unsuspected in patients undergoing thoracotomy for a localized surgical problem. Seven patients had significantly reduced single-breath diffusing capacity for carbon monoxide (36 to 69 per cent of predicted) and abnormalities in maximal expiratory flow-volume curves, especially at small lung volumes. Maximal expiratory flow was only slightly reduced at 20 per cent of total vital capacity exhaled (57 to 90 per cent of predicted), but was markedly reduced (17 to 46 per cent of predicted) at 80 per cent of total vital capacity exhaled. Despite these physiologic abnormalities, all patients had normal or questionably abnormal values for vital capacity, total lung capacity, forced expiratory volume in one second, and airway resistance. Anatomic studies of lobes or lungs removed within a week after physiologic studies revealed diffuse emphysema in these 7 patients. T...