Reversibility of airway obstruction in relation to prognosis in chronic obstructive pulmonary disease

Whether reversibility in airway obstruction with beta-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.