<正> 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.