The Relationship between Tracheobronchial Collapse and Pulmonary Function in Chronic Obstructive Pulmonary Disease

¹ Respiratory Research Laboratory, Toronto General Hospital and the Departments of Medicine and Radiology, University of Toronto
² Assistant Professor, Department of Radiology, University of Toronto
³ Research Associate, Department of Medicine, University of Toronto
⁴ Assistant Professor, Department of Medicine, University of Toronto

Ten patients with pulmonary emphysema have been studied using cinebronchography during five phases of respiration and the results related to pulmonary function tests. An abnormal degree of tracheobronchial collapse has been noted in seven patients, but only during the performance of the maximum voluntary ventilation or coughing. There appears to be no correlation between the severity of the airway collapse and the degree of airway obstruction as shown by abnormal tests of ventilation. Similarly, there was no relationship between airway collapse and tests of gas exchange.

Three patients without cough and sputum showed no significant tracheobronchial collapse. The presence of chronic bronchitis with sputum therefore appears to be an important factor in weakening the tracheobronchial wall and predisposing to large airway narrowing.

It is concluded that in chronic obstructive lung disease, the severity of the airway obstruction is probably due to difficulty with air flow in the distal rather than the more proximal parts of the bronchial tree. It is suggested that supportive surgery of the trachea and major airways should be reserved for patients who have significant amounts of tracheobronchial secretions.

Improvement following surgery is probably due to greater ease in clearing secretions rather than to relief of the obstruction to air flow itself.