Pulmonary Function Studies in Patients with Upper Airway Obstruction ^1, ²

Abstract

Upper airway obstruction is an important, often unrecognized cause of dyspnea and hypercapnea, even in patients with normal expiratory spirogram. Studies of 9 patients with various causes of upper airway obstruction demonstrated the importance of inspiratory flow in detecting and evaluating this lesion and the value of the flow-volume plot, and direct measurement of the upper airway resistance in defining the dynamic nature of the obstruction.