Effect of erythrocyte storage and oxyhemoglobin affinity changes on cardiac function

Storage of blood can depress erythrocyte 2,3-diphosphoglycerate (DPG) levels and thereby increase oxyhemoglobin affinity and potentially decrease capillary-to-tissue oxygen transport. We measured myocardial function and metabolism in isolated rabbit hearts with fixed coronary flow under basal conditions and during isoproterenol stress at 37 and 30 degrees C, comparing high and low oxyhemoglobin affinity (OHA) erythrocytes. The high OHA state resulted from standard storage conditions, which caused depressed values of DPG and P50 (the oxygen tension at which hemoglobin is 50% saturated). The low OHA erythrocytes were initially stored and then underwent biochemical treatment to restore the DPG and P50 values to normal. The low OHA cells released more oxygen, and myocardial oxygen consumption and contractile function were increased relative to the high OHA cells during both the basal and stress states at both 37 and 30 degrees C. These observations may be relevant for patients with limited coronary flow when such patients receive large transfusions of stored blood.