Background
Stored red blood cells (RBCs) are deficient in 2,3-diphosphoglycerate (2,3-DPG), but it is unclear how autologous salvaged blood (ASB) compares to stored blood, and how rapidly 2,3-DPG levels return to normal after transfusion. Therefore, we compared levels of 2,3-DPG in stored versus ASB RBCs, and in patients’ blood following transfusion.
Methods
Twenty-four patients undergoing multilevel spine fusion surgery were enrolled. We measured 2,3-DPG and the oxyhemoglobin dissociation curve (P50) in samples taken from the ASB and stored blood-bags before transfusion, and in blood samples drawn from patients before and after transfusion.
Results
The mean storage duration for stored RBCs was 24 ± 8 days. Compared with fresh RBCs, stored RBCs had decreased 2,3-DPG levels (by ≈ 90%; P<0.0001), and a decreased P50 (by ≈ 30%; P<0.0001). However, ASB RBCs did not exhibit these changes. The mean 2,3-DPG concentration decreased by ≈ 20% (P<0.05) in postoperative blood sampled from patients who received 1 – 3 stored RBC units, and by ≈ 30% (P<0.01) in those who received ≥4 stored RBC units. 2,3-DPG was unchanged in patients who received no stored blood or ASB alone. After surgery, 2,3-DPG levels recovered gradually over three postoperative days in patients who received stored RBCs.
Conclusions
Stored RBCs, but not ASB RBCs, have decreased levels of 2,3-DPG and a left shift in the oxyhemoglobin dissociation curve. Postoperatively, 2,3-DPG levels remain below preoperative baseline levels for up to three postoperative days in patients who receive stored RBCs, but are unchanged in those who receive only ASB RBCs.