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%) within 15 minutes of transfusion. 1, 2
Clinical Reasoning
Why TRALI is the Primary Diagnosis
TRALI characteristically presents with non-cardiogenic pulmonary edema within 1-2 hours after transfusion, with the hallmark triad of hypoxemia, dyspnea, and hypotension. 2 The timing (15 minutes post-transfusion) and presentation (hypotension + hypoxemia) are classic. 1, 3
The presence of hypotension rather than hypertension is a key diagnostic feature that distinguishes TRALI from TACO (circulatory overload). 2 TACO would present with hypertension and cardiovascular changes suggesting fluid overload, not hypotension. 2, 3
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. 2, 3
Why NOT Acute Hemolytic Transfusion Reaction (Option A)
Acute hemolytic transfusion reactions typically present with fever, pain (back/chest), restlessness, nausea, skin flushing, and hemoglobinuria/jaundice—not primarily with isolated hypotension and hypoxemia. 4, 5
While hypotension can occur in hemolytic reactions, it is usually accompanied by other distinctive features like intravascular hemolysis, DIC, and renal failure that develop through complement activation. 5 The isolated respiratory compromise (SpO2 88%) points away from this diagnosis.
Hemolytic reactions cause symptoms mediated by complement cleavage products (C3a, C5a), leading to a systemic inflammatory response, bleeding complications, and renal failure—not primarily acute lung injury. 4
Why NOT Simple Allergic Reaction (Option C)
Allergic reactions typically present with urticaria, rash, pruritus, and possibly bronchospasm—not profound hypotension and severe hypoxemia as the primary features. 6
The severity and rapidity of cardiovascular collapse with respiratory failure exceeds what would be expected from a simple allergic reaction (unless anaphylaxis, which would include other features like angioedema and bronchospasm). 6
Immediate Management Algorithm
First 5 Minutes
Stop the transfusion immediately and maintain IV access with normal saline. 1, 2, 3
Administer 100% oxygen (high FiO2) to address the severe hypoxemia. 1, 2, 3
Call for help and prepare for potential intubation and mechanical ventilation. 2
Next 15-30 Minutes
Maintain adequate blood pressure with IV fluid resuscitation using normal saline or lactated Ringer's solution. 2 If hypotension persists despite fluids, prepare vasopressors (epinephrine, ephedrine, phenylephrine). 7
Send baseline labs immediately: CBC, PT, aPTT, fibrinogen, direct antiglobulin test (DAT), repeat cross-match, and visual inspection of plasma for hemolysis. 1, 2
Contact the transfusion laboratory immediately to report the reaction and initiate investigation. 6, 1
Critical Pitfalls to Avoid
DO NOT administer diuretics—they are ineffective and potentially harmful in TRALI. 2, 3 TRALI requires supportive care with oxygen therapy and critical care measures, not volume removal. 2
Do not assume this is TACO (fluid overload) based on the pulmonary symptoms alone. TACO would present with hypertension, not hypotension. 2, 3
Do not delay oxygen therapy while waiting for laboratory confirmation. The first priority is oxygenation and hemodynamic support. 1, 2
Post-Stabilization Actions
Report the reaction to the blood bank immediately to remove the implicated donor from the pool. 2 TRALI is underdiagnosed and underreported despite being a leading cause of transfusion-related mortality. 1, 2
Continue observation for at least 24 hours, as TRALI can evolve over the first 6-12 hours post-transfusion. 2
Monitor vital signs every 5-15 minutes until stable. 1