Reversibility of Airway Obstruction in Relation to Prognosis in Chronic Obstructive Pulmonary Disease

¹ From the First Department of Medicine, School of Medicine, Hokkaido University, Sapporo, Japan

Whether reversibility in airway obstruction with β-adrenergic stimulant is a significant determinant for the outcome was tested in 59 patients with pulmonary emphysema and chronic bronchitis. During four years of follow-up, 43 (73 percent) patients survived and 16 (27 percent) died. Initial VC, FVC, FEV₁, and PaO₂ were significantly smaller, and PaCO₂ was significantly larger in nonsurvivors than those in survivors. After orciprenaline sulfate (10 mg in 0.5 ml solution) inhalation, VC and FEV₁ increased in comparable amount between the two groups. Airway reversibility as estimated by percentage changes in FEV₁ before and after the bronchodilator (reversibility index) was similar between the two groups. In the 16 nonsurvivors, hypoxemic patients had similar FEV₁, FEV₁/FVC, and reversibility indices as normoxemic patients. These results indicate that not airway reversibility per se but a fixed or irreversible component of airway obstruction is one of the determinants of the prognosis in pulmonary emphysema and chronic bronchitis. Chronic hypoxemia is related to neither airway obstruction nor its reversibility, while it does influence the prognosis.