For a patient with anemia, is Packed Red Blood Cells (PRBC) or Whole Blood more preferable?

Packed Red Blood Cells (PRBCs) Are Strongly Preferred Over Whole Blood for Anemia

PRBCs are the preferred blood product for transfusion to correct anemia in virtually all clinical scenarios. 1 Whole blood is no longer the standard of care and has been largely replaced by component therapy in modern transfusion medicine. 2

Why PRBCs Are Superior

Concentration and Efficacy

• PRBCs deliver a higher concentration of red blood cells per unit volume (hematocrit 50-80%) compared to whole blood, providing more efficient correction of oxygen-carrying capacity. 1
• Each 300 mL unit of PRBCs contains 42.5-80 g of hemoglobin and typically raises hemoglobin by approximately 1 g/dL in normal-sized adults without ongoing blood loss. 1, 3
• This concentrated formulation allows for more precise hemoglobin correction while minimizing volume overload, a critical consideration in patients with cardiovascular or renal disease. 1

Component Therapy Advantages

• PRBCs allow targeted correction of anemia without unnecessary transfusion of plasma, platelets, or clotting factors that the patient may not need. 2
• When plasma or coagulation factors are required, fresh frozen plasma (FFP) can be given separately and in appropriate ratios based on clinical need. 2
• Platelet transfusions can be administered independently when thrombocytopenia develops, guided by platelet counts rather than empirically. 2

Safety Enhancements

• PRBCs can be modified with leukoreduction, irradiation, freezing, and washing to reduce specific transfusion risks. 1
• Leukoreduction decreases the incidence of febrile nonhemolytic transfusion reactions, the most common adverse reaction. 1
• CMV-negative PRBCs can be selected for immunocompromised patients when needed. 1

Clinical Application Guidelines

Transfusion Thresholds

• Transfuse when hemoglobin falls below 7 g/dL in hemodynamically stable patients, including critically ill patients requiring mechanical ventilation and resuscitated trauma patients. 1, 4
• Consider transfusion at hemoglobin 8 g/dL or below in patients with preexisting cardiovascular disease or symptoms of inadequate tissue oxygenation. 1, 4
• The decision should incorporate clinical symptoms (tachycardia >110 bpm, tachypnea, dyspnea, confusion) and biochemical markers (elevated lactate, low pH, low mixed venous oxygen saturation), not hemoglobin level alone. 1, 5

Administration Protocol

• Order PRBCs one unit at a time and reassess clinically after each unit before deciding whether additional transfusion is needed. 1, 3
• PRBCs must be crossmatched for ABO compatibility before transfusion. 3
• Premedication with acetaminophen or antihistamines is rarely required unless repeated transfusions are anticipated. 1, 3

Special Populations

• Cancer patients with chemotherapy-induced anemia: PRBCs provide the only option for immediate correction when rapid hemoglobin increase is needed. 1
• Critically ill patients: A restrictive strategy (transfusion trigger <7 g/dL) is as effective as liberal strategy (trigger <10 g/dL) and avoids unnecessary transfusion risks. 1
• Cardiac disease patients: Higher thresholds (7-8 g/dL) may be appropriate, but liberal transfusion strategies show no benefit. 1

Risks to Consider

Transfusion-Associated Complications

• PRBCs carry risks including venous thromboembolism (OR 1.60), arterial thromboembolism (OR 1.53), and increased mortality (OR 1.34) in cancer patients. 1, 3
• Transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) remain important complications requiring vigilance. 1
• Febrile nonhemolytic reactions are the most common adverse event, though leukoreduction has significantly reduced their incidence. 1

Iron Overload

• Transfusion-related iron overload occurs in patients requiring frequent transfusions over several years (e.g., myelodysplastic syndromes). 1
• This is unlikely in patients receiving transfusions for less than one year during chemotherapy treatment. 1

Common Pitfalls to Avoid

• Do not transfuse based solely on a hemoglobin threshold—always assess the patient's symptoms, comorbidities, volume status, and evidence of tissue hypoxia. 1, 4, 5
• Avoid ordering multiple units simultaneously—transfuse one unit at a time with clinical reassessment to prevent overtransfusion. 1, 3
• Do not assume transfusion corrects underlying iron deficiency—obtain pre-transfusion iron studies and provide supplemental iron therapy if indicated. 3
• Recognize that hemodilution can cause falsely low hemoglobin values—assess volume status before deciding to transfuse. 5
• Remember that PRBCs provide only temporary correction—they do not address the underlying cause of anemia and have no lasting effect. 4