What is the diagnosis for a patient with a history of diabetes, hypertension, and chronic heart failure who develops hypotension and hypoxemia (SpO2 of 88%) 15 minutes after a blood transfusion?

Diagnosis: Transfusion-Related Acute Lung Injury (TRALI)

The diagnosis is B. Acute lung injury (TRALI), based on the characteristic presentation of hypotension and hypoxemia occurring within 15 minutes of transfusion in a patient with chronic heart failure. 1, 2

Clinical Reasoning

Why TRALI is the Most Likely Diagnosis

TRALI characteristically presents with non-cardiogenic pulmonary edema within 1-2 hours after transfusion, with the hallmark triad of hypoxemia, dyspnea, and hypotension. 1, 2 The timing (15 minutes post-transfusion), combined with hypotension (not hypertension) and severe hypoxemia (SpO2 88%), fits this diagnosis precisely. 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, 2 TRALI is a leading cause of transfusion-related mortality despite being underdiagnosed and underreported. 1, 3

Why NOT Acute Hemolytic Transfusion Reaction (Option A)

While acute hemolytic transfusion reactions can cause hypotension, they typically present with a different constellation of symptoms including fever, back pain, dark urine, and disseminated intravascular coagulation. 4 The prominent hypoxemia (SpO2 88%) is not a primary feature of hemolytic reactions. 4 Hemolytic reactions occur in approximately 1:70,000 units transfused and are usually caused by ABO incompatibility. 4

Why NOT Simple Allergic Reaction (Option C)

Allergic reactions typically present with urticaria, pruritus, and bronchospasm, but not with the severe hypotension and profound hypoxemia seen in this case. 5 The 2025 Association of Anaesthetists guidelines distinguish between allergic reactions (which require antihistamines) and more severe reactions like TRALI. 5 Simple allergic reactions would not cause SpO2 to drop to 88% or produce significant hypotension. 5

Critical Distinguishing Feature: Hypotension vs. Hypertension

The presence of hypotension rather than hypertension is the key diagnostic feature that distinguishes TRALI from TACO (transfusion-associated circulatory overload). 1 TACO, which is now the most common cause of transfusion-related mortality, presents with hypertension, tachycardia, and evidence of fluid overload. 5 This patient's chronic heart failure increases TACO risk, but the hypotension rules it out. 5

Immediate Management Protocol

First Actions (Within Seconds)

• Stop the transfusion immediately and maintain IV access with normal saline. 1, 2
• Administer 100% oxygen to address the severe hypoxemia (SpO2 88%). 1, 2
• Call for help and prepare for potential intubation and mechanical ventilation. 1, 2

Hemodynamic Support

• Maintain adequate blood pressure with IV fluid resuscitation using normal saline or lactated Ringer's solution. 1, 2
• Avoid diuretics—they are ineffective and potentially harmful in TRALI. 1, 2 This is a critical pitfall, as TRALI requires supportive care with oxygen therapy and critical care measures, not volume removal. 1

Critical Pitfall to Avoid

Do not administer diuretics thinking this is fluid overload (TACO). 1 Given this patient's history of chronic heart failure, there may be a strong temptation to treat with diuretics, but this would be harmful. TACO would present with hypertension and cardiovascular changes suggesting fluid overload, not hypotension. 1

Post-Stabilization Actions

• Transfer to intensive care for continued monitoring and mechanical ventilation if needed. 2
• Report the reaction to the blood bank immediately to remove the implicated donor from the pool. 1, 2
• Continue observation for at least 24 hours, as TRALI can evolve over the first 6-12 hours post-transfusion. 1, 2
• Send post-reaction blood samples for complete blood count, direct antiglobulin test, repeat crossmatch, PT, aPTT, and fibrinogen to exclude hemolytic reaction. 1

Additional Context for This Patient

The patient's comorbidities (diabetes, hypertension, chronic heart failure) place them at higher risk for both TACO and TRALI. 5 However, the clinical presentation with hypotension definitively points to TRALI rather than TACO. 1 The 2025 Association of Anaesthetists guidelines emphasize that dyspnea and tachypnea are typical early symptoms of serious transfusion reactions, and respiratory rate should be monitored throughout transfusion. 5