What are the criteria for blood and platelet transfusions?

Criteria for Blood and Platelet Transfusions

Blood Transfusion Criteria

Blood transfusions should be administered when hemoglobin levels fall below 7 g/dL in most hospitalized adult patients without extenuating circumstances. 1

This restrictive transfusion strategy is supported by high-quality evidence and has been shown to be safe while reducing unnecessary transfusions. However, there are important clinical scenarios where different thresholds apply:

Special Circumstances for Blood Transfusions:

• Extenuating circumstances requiring higher thresholds (≥9 g/dL):

  • Myocardial ischemia
  • Severe hypoxemia
  • Acute hemorrhage
  • Ischemic heart disease 1

• Gastrointestinal bleeding: Restrictive strategy (7 g/dL) is recommended over liberal strategy (9 g/dL) with moderate certainty evidence 1

• Symptomatic anemia: Transfusion may be indicated regardless of specific hemoglobin level when patients exhibit:

  • Shortness of breath
  • Dizziness
  • Congestive heart failure
  • Decreased exercise tolerance 2

Clinical Considerations for Blood Transfusions:

• Each unit of RBCs typically raises hemoglobin by approximately 1 g/dL 3
• Transfusion-related complications include procedural problems, iron overload, infections, and immune injury
• Recent evidence suggests that transfusion at hemoglobin <7 g/dL compared to no transfusion does not improve organ dysfunction in critically ill patients 4
• Young, healthy patients may tolerate lower hemoglobin levels without increased risk of complications 5

Platelet Transfusion Criteria

Prophylactic platelet transfusions should be given when platelet counts fall below 10,000/mm³ (10 × 10⁹/L) in hospitalized adult patients with therapy-induced hypoproliferative thrombocytopenia to reduce the risk of spontaneous bleeding. 1

Platelet Transfusion Thresholds for Different Clinical Scenarios:

1. Hospitalized patients with therapy-induced thrombocytopenia:

   • Transfuse when platelet count ≤10 × 10⁹/L 1
   • Single apheresis unit or equivalent is recommended (higher doses not more effective) 1

2. Invasive procedures:

   • Central venous catheter placement: Transfuse when platelet count <20 × 10⁹/L 1
   • Lumbar puncture: Transfuse when platelet count <50 × 10⁹/L 1
   • Major non-neuraxial surgery: Transfuse when platelet count <50 × 10⁹/L 1
   • Neurosurgery: Consider transfusion when platelet count <80-100 × 10⁹/L 1

3. Active bleeding:

   • Transfuse to maintain platelet count ≥50 × 10⁹/L 1

4. Sepsis with significant bleeding risk:

   • Transfuse when platelet count <20 × 10⁹/L 1

Important Considerations for Platelet Transfusions:

• Outpatients may require more liberal thresholds for practical reasons (fewer clinic visits) 1
• Low-dose platelet transfusions are as effective as standard or high-dose for preventing bleeding but may need to be given more frequently 1
• Platelet transfusions have risks including allergic reactions, febrile non-hemolytic reactions, and bacterial contamination 1

Common Pitfalls to Avoid

1. Over-transfusion: Transfusing at higher thresholds than necessary increases risks without providing additional benefits

   • Each unit of blood carries risks and should be given only when clearly indicated

2. Ignoring clinical context: Rigid adherence to numerical thresholds without considering the patient's clinical status

   • Symptomatic patients may benefit from transfusion at higher hemoglobin levels

3. Failure to reassess: Not evaluating the patient's response to transfusion

   • Clinical symptoms may persist despite correction of laboratory values

4. Prophylactic platelet transfusions in all thrombocytopenic patients: Not all thrombocytopenic patients require prophylactic platelet transfusions

   • Evidence supports specific thresholds for different clinical scenarios

5. Transfusing fresh frozen plasma for laboratory abnormalities: FFP should not be used to correct laboratory clotting abnormalities in the absence of bleeding or planned invasive procedures 1

By following these evidence-based criteria for blood and platelet transfusions, clinicians can optimize patient outcomes while minimizing unnecessary transfusions and their associated risks.