Oxygen affinity and 2,3-diphosphoglycerate level of erythrocytes in patients with cor pulmonale

Arterial blood gases,intraerythrocytic pH (pHi),2,3-diphosphoglycerate,standardP 50 (P 50std) and in vivo P 50 (P 50iv) were determined in 54 patients with cor pulmonale and23 normal subjects.It was found that no significant change of pHi was observed but the differ-ence of pHi and extraerythrocytic pH was decreased.P 50std was significantly decreased whileP 50iv remained essentially unchanged in those cases showing type I respiratory failure.Thesefindings suggest that P 50std cannot accurately reflect the changes of P 50iv in patients of corpulmonale;P 50iv in cases of cor pulmonale usually keeps relatively stable and coincides withthe ‘optimal P 50’,which indicates the adaptation of the organism to chronic hypoxia;and rel-ative intraerythrocytic alkalosis plays an important role in the relief of hypercapnia in cases ofcor pulmonale.