What is the diagnosis for a patient who develops hypotension and decreased oxygen saturation (SpO2) of 88% within 15 minutes after a blood transfusion?

Diagnosis: Transfusion-Related Acute Lung Injury (TRALI)

The most likely diagnosis is TRALI (Option B: Acute lung injury), given the characteristic presentation of hypotension combined with severe hypoxemia (SpO2 88%) occurring within 15 minutes of transfusion. 1, 2, 3

Key Diagnostic Features Supporting TRALI

The presence of hypotension rather than hypertension is the critical distinguishing feature that points to TRALI over other transfusion reactions. 2, 3 TRALI characteristically presents with the hallmark triad of:

• Hypoxemia (SpO2 88% in this case) 2, 3
• Hypotension (not hypertension) 2, 3
• Dyspnea/respiratory distress 1, 2

The timing is also classic: TRALI typically presents within 1-2 hours after transfusion, with approximately half of cases occurring within the first 15 minutes. 1, 2, 4

Why Not the Other Options?

Acute Hemolytic Transfusion Reaction (Option A) - Less Likely

While acute hemolytic reactions can present rapidly, the dominant feature would be signs of intravascular hemolysis including:

• Pain (back pain, chest pain) 5
• Fever and rigors 5, 6
• Hemoglobinuria and jaundice 5
• Restlessness and skin flushing 5

The primary presentation of profound hypoxemia (SpO2 88%) with hypotension is more characteristic of TRALI than hemolytic reaction. 2, 3 Hemolytic reactions typically cause hypotension through complement activation and DIC, but severe hypoxemia is not the predominant early feature. 5, 6

Allergic Reaction (Option C) - Least Likely

Allergic reactions typically present with:

• Urticaria and pruritus 2
• Bronchospasm (which could cause hypoxemia, but not typically this severe) 2
• Hypertension or normal blood pressure, not hypotension 2

The combination of severe hypotension with profound hypoxemia makes a simple allergic reaction unlikely. 2

Pathophysiology of TRALI

TRALI occurs when donor leukocyte antibodies (HLA class I, class II, or granulocyte-specific antibodies) interact with recipient neutrophils, causing non-cardiogenic pulmonary edema. 1, 2, 3 This results in acute respiratory distress and cardiovascular instability within 1-2 hours of transfusion. 1, 2

Critical Management Pitfall to Avoid

Do NOT administer diuretics - this is the most dangerous error in TRALI management. 2, 3 TRALI is non-cardiogenic pulmonary edema requiring supportive care with oxygen therapy, not volume removal. 2 Diuretics are ineffective and potentially harmful. 2, 3

If this were TACO (circulatory overload), you would see hypertension and cardiovascular changes suggesting fluid overload, not hypotension. 1, 2 TACO would be treated with diuretics, but TRALI would not. 1

Immediate Management Algorithm

1. Stop the transfusion immediately and maintain IV access with normal saline 2, 3
2. Administer 100% oxygen (high FiO2) to address severe hypoxemia 2, 3
3. Call for help and prepare for potential intubation and mechanical ventilation 2, 3
4. Maintain blood pressure with IV fluid resuscitation using normal saline or lactated Ringer's solution 2, 3
5. Send baseline labs immediately: CBC, PT, aPTT, fibrinogen, direct antiglobulin test (DAT), repeat cross-match 3
6. Report to blood bank immediately to remove the implicated donor from the pool 2, 3

TRALI is a leading cause of transfusion-related mortality despite being underdiagnosed and underreported. 2 Continue observation for at least 24 hours, as TRALI can evolve over the first 6-12 hours post-transfusion. 2, 3