Diagnosis: Transfusion-Related Acute Lung Injury (TRALI)
The most likely diagnosis is TRALI (Option B), given the acute onset of hypotension and severe hypoxemia (SpO2 88%) within 15 minutes of blood transfusion. 1
Clinical Reasoning
Why TRALI is Most Likely
TRALI presents with non-cardiogenic pulmonary edema resulting from immune reactivity, with signs and symptoms appearing 1-2 hours after transfusion (though can occur as early as 15 minutes), characterized by hypoxemia, dyspnea, and hypotension. 1 The combination of:
- Acute hypotension (not hypertension)
- Severe hypoxemia (SpO2 88%)
- Timing: 15 minutes post-transfusion
This triad strongly suggests TRALI rather than the other options. 1
Why NOT Acute Hemolytic Transfusion Reaction (Option A)
While acute hemolytic transfusion reactions (AHTR) can present with hypotension within minutes of transfusion 2, 3, the dominant feature is typically hemolysis-related symptoms including:
- Fever and chills
- Flank or back pain
- Hemoglobinuria (dark/red urine)
- Disseminated intravascular coagulation
- Acute kidney injury 3
The prominent respiratory failure (SpO2 88%) without mention of hemolysis, fever, or pain makes AHTR less likely. 3 AHTR would be expected to show evidence of intravascular hemolysis on laboratory testing. 3
Why NOT Allergic Reaction (Option C)
Allergic reactions typically present with urticaria, pruritus, and bronchospasm (wheezing), but severe hypotension with profound hypoxemia is more characteristic of anaphylaxis or TRALI. 4
If this were anaphylaxis (severe allergic reaction), you would expect:
- Bronchospasm with wheezing
- Urticaria or angioedema
- Cardiovascular collapse
- Response to epinephrine 4
The absence of mentioned bronchospasm or skin findings, combined with the severe hypoxemia, makes TRALI more likely than a simple allergic reaction. 4
Immediate Management Required
Stop the transfusion immediately and maintain IV access with normal saline. 1, 4
Critical Interventions for TRALI
- Administer 100% oxygen (high FiO2) immediately to address the severe hypoxemia 1
- Provide critical care supportive measures including potential mechanical ventilation if respiratory failure progresses 1
- Avoid diuretics - this is crucial as TRALI is non-cardiogenic pulmonary edema and diuretics are ineffective and potentially harmful 1, 4
- Maintain adequate blood pressure with IV fluids and vasopressors if needed (MAP >65-70 mmHg) 1
Diagnostic Workup
- Notify transfusion laboratory immediately and send the blood component bag with administration set for analysis 1, 4
- Send baseline labs: CBC, PT, aPTT, fibrinogen, direct antiglobulin test (DAT), repeat cross-match 1
- Monitor vital signs every 5-15 minutes: heart rate, blood pressure, temperature, respiratory rate, oxygen saturation 1, 4
Key Differentiating Features
| Feature | TRALI | TACO | AHTR |
|---|---|---|---|
| Timing | 1-2 hours (can be <15 min) [1] | During or up to 12 hours [5] | Minutes [2,3] |
| Blood Pressure | Hypotension [1] | Hypertension [5] | Hypotension [2] |
| Pulmonary Edema | Non-cardiogenic [1] | Cardiogenic [5] | Absent |
| Response to Diuretics | No response [1] | Responds [5] | N/A |
| Hemolysis | Absent | Absent | Present [3] |
| BNP/NT-proBNP | Normal or low [5] | Elevated [5] | Normal |
Common Pitfalls to Avoid
- Do not give diuretics empirically - they are contraindicated in TRALI and will not help 1, 4
- Do not restart transfusion even if symptoms improve, as the reaction may worsen with continued exposure 4
- Do not delay oxygen therapy while waiting for diagnostic confirmation 1
- Do not attribute hypoxemia to other causes without considering transfusion reaction first 4