Hemoglobin-oxygen affinity in anemia

Summary In blood of 21 anemic patients and 8 normal subjects (N) thre oxygen dissociation curves each were measured at different pH values to calculate Bohr coefficients after acidification with CO₂ (BC_CO2) or fixed acid (BC_FA), and other important parameters of oxygen affinity. The patients had either low hemoglobin or red cell production (L:n=11, 7.3 g/dl Hb) or high erythrocyte production combined with high loss (H:n=10, 7.8 g/dl Hb). The standard half saturation pressure P₅₀ (pH 7.4, 37°C) was equally elevated in both anemic groups (L:30.5, H:30.8, N:26.7 mmHg), as well as the diphosphoglycerate concentration (DPG) (L:18.7, H:18.6, N:12.7 mol/g Hb). The red cell pH of the anemics was lower than for the N (approximately 0.045 units) causing part of the difference in P₅₀. Hill's ntended to high values in the anemics except at low O₂-saturation in the H. For BC_CO2 no significant difference among the groups was observed. BC_FA, however, increased in the H at low S_O2 compared to the N and L. The cause for most of the changes in hemoglobin oxygen affinity in anemics was the high [DPG]. The combination of high P₅₀ and high n value as in the L seems to be most advantageous for tissue oxygenation.The measurements were performed during a stay as visiting professor at the Universidad del Valle, supported by Deutscher Akademischer Austauschdienst VS 931 509 0013