Erythrocyte pH in respiratory and metabolic acid-base disturbances. Studies on human blood in vitro.

The influence of oxygenation in respiratory and metabolic acid-base disturbances on erythocyte pH has been studied on normal human blood "in vitro". In physiological pH range, pHe-pHi relationship is the same for PCO2 variations at constant metabolic level and for metablic level variations at constant PCO2. A "global" pHe-pHi relationship has been calculated at 0 and 100% SO2. The oxygen-linked pH shift depends on pH level and PCO2 and is different in plasma and erythrocyte. From these results arise conclusions on pHi and pHe dependency, physiological role of saturation level of hemoglobin and conditions of P50 normalisation at pH 7.4.