The oxyhemoglobin dissociation curve in patients with familial hyperchylomicronemia.

In order to study the effect of marked chylomicronemia on red cell oxygen release, oxygen hemoglobin dissociation curves (ODC's) from zero to full saturation were determined on whole blood from three siblings with familial Type I hyperlipoproteinemia. In these cases the oxygen affinity of hemoglobin was markedly increased, with P50 act. pH varying between 22.1 and 17.7 mm. Hg (normal value, 27.3 mm. Hg; S.D., 1.3) and the Hill coefficient n reflecting the slope of the ODC was increased. The changes in the ODC's are thought to be secondary to the hyperchylomicronemia for the following reasons: (1) the change was minimized by incubating red cells from the patients in normal donor plasma; (2) normal red cells increased their oxygen affinity when incubated in lactescent plasma; (3) the change was not explainable by a decrease in red cell 2,3-diphosphoglycerate content or in arterial blood hydrogen ion concentration. Based on these findings a decreased erythrocyte oxygen release of one third can be hypothesized. The importance of this observation in relation to the symptomatology of clinical conditions complicating marked chylomicronemia is discussed.