Lesson 5: Blood Storage

Blood Storage Overview

• One unit of packed red blood cells (PRBCs) ≈ 300 mL, hematocrit 70%.
• Transfusion of one unit raises hemoglobin by 1 g/dL and hematocrit by 2-3%.

Anticoagulants and Additives

• Citrate: Anticoagulant; inhibits calcium (factor 4); excess can cause hypocalcemia.
• Phosphate: Buffer to combat acidosis.
• Dextrose: Primary substrate for glycolysis.
• Adenine: Substrate for ATP synthesis, extends RBC storage from 21 to 35 days.
• New preservatives (Adsol, Nutricel, Optisol) can extend storage to 42 days.

RBC Storage Lesion Consequences

• Decreased 2,3-DPG → left shift in oxyhemoglobin dissociation curve (decreased O2 release).
• Decreased ATP and pH (increased lactic acid).
• Increased potassium (risk in neonates and renal failure).
• Impaired shape change ability (affects capillary flow).
• Hemolysis and increased proinflammatory mediators.

Component Processing Techniques

Leukoreduction

• Removes WBCs from RBCs and platelets to reduce HLA sensitization, febrile nonhemolytic transfusion reactions, and CMV transmission.

Washing

• Removes remaining plasma and antigens, preventing anaphylaxis in IgA deficient patients.

Irradiation

• Exposes blood to gamma radiation, destroying donor leukocytes to prevent graft-vs-host disease in immunocompromised patients.
• Beneficial for patients with leukemia, lymphoma, stem cell transplants, and DiGeorge syndrome.