The oxyhemoglobin dissociation curve in type A and type B COPD.

Abstract

Patients with chronic obstructive pulmonary disease (COPD) have been clinically separated into Type A and Type B COPD. Type A patients are characterized by the presence of anatomical emphysema or an increased total lung capacity, low sputum production, late onset of cough, rare hypercapnia, rare cor pulmonale and absent polycythemia. In contrast, Type B patients are characterized by roentgenographic evidence of chronic inflammation or smaller total lung capacity, significant sputum production, frequent hypercapnia with cor pulmonale and the presence of polycythemia. We studied whole blood oxygen transport (P50, 2,3-DPG, and ATP) in 11 Type A patients and 13 Type B patients. Whole blood oxygen transport was not different in the two groups of patients. Type A patients with higher hemoglobin values had a lower 2,3-DPG. Type A patients with a higher hemoglobin value also had a higher ATP level. In all patients, Type A and Type B, 2,3-DPG was inversely related to hemoglobin concentration. Despite other distinguishing clinical and laboratory characteristics, whole blood oxygen transport was not different in Type A and Type B patients.