[Hemoglobin oxygen affinity in children on chronic hemodialysis]

We have studied the changes induced by hemodialysis in the blood oxygen affinity in a group of 8 children with chronic kidney failure. Before dialysis: the affinity was low - P50 (7.40) = 28,3 Torr. Such a decreased affinity could explain in part why the important anemia (2 million RBC on average) observed in these patients was well tolerated. The observed decrease in hemoglobin oxygen affinity was attributed to an increase in 2-3 diphosphoglycerate (2-3 DPG) concentration, resulting from a high level of inorganic phosphates. After dialysis: the plasmatic pH increased markedly (7.52) with a consequent increase in the blood oxygen affinity in vivo (Bohr effect). No substantial change in 2-3 DPG concentration on P50 (7.40) occurred during hemodialysis.