Can diffuse alveolar hemorrhage (DAH) occur after a Packed Red Blood Cell (PRBC) transfusion?

Diffuse Alveolar Hemorrhage After PRBC Transfusion

Yes, diffuse alveolar hemorrhage (DAH) can occur after packed red blood cell (PRBC) transfusion as a manifestation of transfusion-related acute lung injury (TRALI), which is a recognized complication of blood product transfusion.

Transfusion-Related Acute Lung Injury and DAH

• TRALI is a serious and potentially life-threatening complication of blood transfusion that can manifest as diffuse alveolar hemorrhage 1
• TRALI has emerged as a leading cause of transfusion-associated morbidity and mortality, despite being underdiagnosed and underreported 1
• The relationship between transfusion and acute lung injury/ARDS is well-established in clinical practice guidelines 1

Pathophysiology

• TRALI typically develops within 6 hours of transfusion and is characterized by respiratory distress, hypoxemia, and bilateral pulmonary infiltrates 1
• The mechanism involves a "two-hit" model where:
  • First hit: Pre-existing lung inflammation (from trauma, surgery, or critical illness)
  • Second hit: Transfusion of blood products containing antibodies or bioactive substances 2
• Stored PRBCs develop a "storage lesion" characterized by reduced deformability, altered adhesiveness, and accumulation of proinflammatory compounds that can trigger lung injury 1

Clinical Presentation

• Patients with DAH following PRBC transfusion typically present with:
  • Acute respiratory distress
  • Hypoxemia requiring oxygen supplementation
  • Diffuse radiographic pulmonary infiltrates
  • Hemoptysis (may be absent initially) 3, 4
• Diagnosis is confirmed by bronchoscopy with increasingly bloody returns on sequential bronchoalveolar lavage or the presence of hemosiderin-laden macrophages 4

Risk Factors

• Transfusion of older stored blood products (>21-28 days old) significantly increases the risk of lung injury 2
• Pre-existing conditions that may increase risk include:
  • Critical illness
  • Trauma with hemorrhagic shock
  • Major surgery
  • Sepsis 1, 2

Management

• All efforts should be made to diagnose and report TRALI to the local blood bank 1
• Supportive care is the mainstay of treatment, including:
  • Respiratory support (oxygen, mechanical ventilation if needed)
  • Hemodynamic stabilization
  • Correction of coagulopathy 4
• Systemic corticosteroids may be considered, though evidence for their efficacy is limited 4
• Platelet transfusions may be necessary if thrombocytopenia is contributing to the hemorrhage 4

Prevention

• Strategies to reduce the risk of TRALI and DAH include:
  • Use of leukoreduced blood products 1
  • Avoiding unnecessary transfusions by adhering to restrictive transfusion strategies 1, 5
  • Using fresher blood products when possible, particularly in high-risk patients 2
  • Considering alternatives to transfusion when appropriate 1

Clinical Implications

• RBC transfusion is independently associated with longer ICU and hospital length of stay, increased complications, and increased mortality 1
• The risk of TRALI must be weighed against the benefits of transfusion in each clinical scenario 5
• A restrictive transfusion strategy (Hb threshold of 7-8 g/dL) is recommended for most hemodynamically stable patients to minimize exposure to transfusion risks 5

DAH following PRBC transfusion represents a serious complication that requires prompt recognition and management. Clinicians should maintain a high index of suspicion in patients who develop respiratory distress following blood product administration.