In a patient who recently received a blood transfusion and now presents with dyspnea, tachypnea, hypertension, elevated B‑type natriuretic peptide and pulmonary edema, does transfusion‑associated circulatory overload respond to diuretics as first‑line therapy?

Does TACO Respond to Diuretics?

Yes—loop diuretics (furosemide) are the definitive first-line therapy for transfusion-associated circulatory overload (TACO) and should be administered promptly when TACO is suspected. 1

Immediate Management Algorithm

When a patient develops dyspnea, tachypnea, hypertension, and pulmonary edema during or within 12 hours of transfusion:

1. Stop or slow the transfusion immediately while maintaining IV access with normal saline 1

2. Administer loop diuretics (furosemide) without delay as the cornerstone of TACO treatment 1

   • Start with 20 mg IV bolus or 3 mg/h continuous infusion 2
   • Double each subsequent dose until clinical response is achieved 2
   • Maximum infusion rate: 24 mg/h; maximum bolus: 160 mg 2
   • Do not exceed 620 mg/day 2

3. Provide supplemental oxygen to correct hypoxemia 1

4. Monitor vital signs every 5–15 minutes (heart rate, blood pressure, respiratory rate, SpO₂) during the acute phase 1

Why Diuretics Work in TACO

TACO is fundamentally hydrostatic (cardiogenic) pulmonary edema caused by volume overload in patients with impaired cardiac or renal reserve. 3 The pathophysiology follows a two-hit model: the first hit is pre-existing cardiac/renal dysfunction rendering the patient volume-intolerant, and the second hit is the transfusion itself. 4, 3 Loop diuretics directly address the volume overload by promoting rapid sodium and water excretion, reducing pulmonary capillary wedge pressure and relieving pulmonary congestion. 5

A rapid clinical response to diuretics helps confirm the diagnosis of TACO, distinguishing it from non-cardiogenic causes of acute respiratory distress. 1

Critical Diagnostic Distinction: TACO vs. TRALI

Do NOT give diuretics if TRALI (transfusion-related acute lung injury) is suspected instead of TACO. 1, 6

TACO presents with:

• Hypertension (systolic >100 mm Hg) 1
• Elevated jugular venous pressure 1
• Peripheral edema 1
• Positive fluid balance 1
• Elevated BNP >300 pg/mL or NT-proBNP >2000 pg/mL 1, 7
• Post/pre-transfusion NT-proBNP ratio >1.5 1, 7

TRALI presents with:

• Hypotension (not hypertension) 1, 6
• Severe hypoxemia 1
• Bilateral pulmonary infiltrates without signs of volume overload 1
• Onset typically 1–2 hours after transfusion 1, 6
• Diuretics are contraindicated—treatment is supportive care with oxygen and mechanical ventilation if needed 1, 6

Evidence Supporting Diuretic Use

The ACC/AHA heart failure guidelines establish that diuretics are the cornerstone of treatment for any patient with fluid overload, and this principle directly applies to TACO. 5 Patients with acute decompensated heart failure and significant volume overload should receive intravenous loop diuretics promptly, with the initial IV dose equaling or exceeding their chronic oral dose. 5 Early intervention with diuretics improves outcomes in volume-overloaded states. 5

In the specific context of TACO, prompt diuretic administration is recommended as definitive therapy by transfusion medicine guidelines. 1 The rapid response to diuretics not only treats the condition but also serves as a diagnostic confirmation. 1

Prophylactic Diuretics: A Nuanced Approach

Prophylactic furosemide may be considered in high-risk patients (age >70 years, heart failure, renal failure with GFR <30 mL/min/1.73 m², hypoalbuminemia, low body weight), but should NOT be used routinely in all transfusion recipients. 2, 8

Evidence is mixed:

• A randomized trial in preterm neonates showed improved oxygen requirements with prophylactic furosemide 1
• However, the overall evidence base for prophylactic use is weak 2
• Furosemide does NOT prevent acute kidney injury and may increase mortality when used inappropriately 2
• Furosemide should ONLY be used for volume overload management, not for AKI prevention 2

Safer prevention strategies include:

• Transfuse "one unit at a time" in non-bleeding patients and reassess before giving additional units 1, 6
• Use slower transfusion rates (≈4–5 mL/kg/h or slower in patients with reduced cardiac output) 1, 2
• Dose blood products based on body weight to avoid over-transfusion 1, 2

Common Pitfalls to Avoid

1. Do NOT withhold diuretics when hypertension and volume-overload signs are present—this delays essential treatment for TACO 1

2. Do NOT continue the transfusion once respiratory distress appears—immediate cessation is the single most critical intervention 1, 6

3. Do NOT assume mild symptoms are benign—TACO is associated with a 3.2-fold increase in in-hospital mortality 1

4. Do NOT give diuretics for TRALI—this is a non-cardiogenic process where diuretics are ineffective and potentially harmful 1, 6

5. Do NOT use excessive concern about hypotension or azotemia as a reason to withhold diuretics—in true volume overload, diuresis should be maintained even if mild decreases in blood pressure or renal function occur, as long as the patient remains asymptomatic 5

Contraindications to Furosemide

Do NOT administer furosemide in:

• Hemodynamic instability or inadequate intravascular volume 2
• Dialysis-dependent renal failure 2
• Oliguria with serum creatinine >3 mg/dL 2
• Within 12 hours after last fluid bolus or vasopressor administration 2
• Neonatal hyperkalemia (furosemide causes metabolic alkalosis that worsens intracellular potassium shifts) 2

Monitoring During Diuretic Therapy

• Continue clinical surveillance for at least 24 hours after transfusion, as TACO may evolve over 6–12 hours 1
• Monitor daily weight, fluid input/output, and vital signs 5
• Check daily electrolytes (potassium, sodium) and renal function (creatinine, BUN) while on IV diuretics 5, 2
• Watch for diuretic-induced complications: hypokalemia, hyponatremia, hypotension, and worsening renal function 5, 2

Escalation Strategies if Initial Diuretics Fail

If the patient does not respond adequately to initial furosemide:

1. Increase the dose or frequency (e.g., switch to twice-daily dosing or continuous infusion) 5
2. Add a second diuretic (e.g., thiazide such as metolazone) for synergistic effect 5
3. Consider low-dose dopamine infusion (2.5–5 mcg/kg/min) to improve renal blood flow and enhance diuresis 5
4. Ultrafiltration may be considered for refractory congestion not responding to medical therapy 5

Documentation and Reporting

Document and report the TACO event to the blood bank—TACO is now the leading cause of transfusion-related mortality, yet remains underrecognized. 1, 6 Reporting improves institutional awareness and prevention strategies. 1