What is the diagnosis for a patient who develops hypotension and low oxygen saturation (SpO2) shortly after a blood transfusion?

Diagnosis: Transfusion-Related Acute Lung Injury (TRALI)

The most likely diagnosis is TRALI (Option B: Acute lung injury), given the acute onset of hypotension and severe hypoxemia (SpO2 88%) occurring within 15 minutes of blood transfusion. 1

Clinical Reasoning

Why TRALI is the Primary Diagnosis

• TRALI presents with non-cardiogenic pulmonary edema within 1-2 hours after transfusion, with key clinical features including hypoxemia, dyspnea, and hypotension. 1 The 15-minute timeframe and combination of hypotension with severe hypoxemia (SpO2 88%) are classic for TRALI. 1

• The mechanism involves donor leukocyte antibodies (HLA class I, class II, or granulocyte-specific antibodies) interacting with recipient neutrophils, causing acute respiratory distress and cardiovascular instability. 1

• TRALI is a leading cause of transfusion-related mortality despite being underdiagnosed and underreported. 1

Why NOT Acute Hemolytic Transfusion Reaction (Option A)

• Acute hemolytic transfusion reactions typically present with the classic triad of fever, back/flank pain, and hemoglobinuria—not primarily with isolated hypotension and hypoxemia. 2 While hypotension can occur, the dominant feature would be evidence of hemolysis (hemoglobinemia, hemoglobinuria, elevated LDH, elevated bilirubin). 2, 3

• The 15-minute timeframe is consistent with both conditions, but the prominent respiratory failure (SpO2 88%) without mention of hemoglobinuria, pain, or fever makes hemolytic reaction less likely. 2

• Acute hemolytic reactions are now rare due to improved blood banking practices and typically require ABO-incompatible transfusion. 2

Why NOT Simple Allergic Reaction (Option C)

• Allergic reactions present with urticaria, pruritus, and bronchospasm (wheezing), but typically do NOT cause profound hypotension and severe hypoxemia unless progressing to anaphylaxis. 4

• The absence of mentioned bronchospasm/wheezing or cutaneous manifestations makes a simple allergic reaction unlikely. 4 If this were anaphylaxis, bronchospasm would be a prominent feature alongside the hypotension. 4

Immediate Management Algorithm

First-Line Actions (Within Seconds)

• Stop the transfusion immediately and maintain IV access with normal saline—this is the single most critical intervention. 1

• Administer 100% oxygen (high FiO2) to address the severe hypoxemia. 1

• Call for help and prepare for potential intubation and mechanical ventilation. 1

Hemodynamic Support

• Maintain adequate blood pressure (MAP >65-70 mmHg) with IV fluid resuscitation using normal saline or lactated Ringer's solution. 1

• Prepare vasopressors (epinephrine, norepinephrine, phenylephrine) if hypotension persists despite fluid resuscitation. 5 In the reported cases, epinephrine, ephedrine, and phenylephrine were used successfully. 5

Critical Distinction: AVOID Diuretics

• Do NOT administer diuretics for TRALI—they are ineffective and potentially harmful. 1 This is a key differentiating point from TACO (transfusion-associated circulatory overload), where diuretics are the primary treatment. 1

• TRALI requires supportive care with oxygen therapy and critical care measures, NOT volume removal. 1

Laboratory Investigation

• Send baseline labs immediately: complete blood count, PT, aPTT, fibrinogen, direct antiglobulin test (DAT), and repeat cross-match. 1

• Notify the transfusion laboratory immediately and send the blood component bag with administration set for analysis. 1, 4

• Monitor for hemolysis markers (LDH, bilirubin, hemoglobinuria) to definitively exclude acute hemolytic reaction. 2, 3

Common Pitfalls to Avoid

• Do not empirically give diuretics for all cases of post-transfusion respiratory distress—this distinguishes TRALI (no diuretics) from TACO (diuretics indicated). 1

• Do not delay oxygen therapy while investigating the cause—hypoxemia requires immediate treatment. 1

• Do not restart the transfusion even if symptoms improve, as the reaction may worsen with continued exposure. 4

• Do not attribute the hypotension solely to surgical blood loss or other causes without considering transfusion reaction. 5

Post-Stabilization Care

• Transfer to intensive care for continued monitoring and mechanical ventilation if needed. 6, 1

• Continue observation for at least 24 hours, as TRALI can evolve over the first 6-12 hours post-transfusion. 1

• Report the reaction to the blood bank to remove the implicated donor from the pool, as donor antibodies are the causative mechanism. 1