Transfusion-associated circulatory overload (TACO)

Overview

TACO presents during transfusion or within 12 hours of completion - acute cardiogenic pulmonary oedema superimposed on the transfusion context.

•Dyspnoea - acute onset or worsening, often first symptom

•Hypertension - cardinal discriminating feature from TRALI

•Tachycardia and tachypnoea

•Bibasal crackles - pulmonary oedema flooding the alveoli

•Raised JVP and peripheral oedema - elevated venous backpressure from volume overload

•Reduced SpO2 - alveolar flooding impairs gas exchange

•Risk factors: elderly, pre-existing heart failure, renal disease

🎯

Hypertension is the single most important discriminator between TACO and TRALI. TACO = hypertension + raised JVP + peripheral oedema (cardiogenic, pressure-driven). TRALI = hypotension + normal JVP + no peripheral oedema (non-cardiogenic, permeability-driven). Both cause bilateral crackles and hypoxia.

Investigations

•Chest X-ray - cardiomegaly, upper lobe diversion, bilateral perihilar ('bat-wing') shadowing, pleural effusions

•BNP/NT-proBNP - markedly elevated in TACO; helps differentiate from TRALI (where BNP normal or mildly raised)

•ABG - type 1 respiratory failure (low PaO2, normal/low PaCO2)

•Fluid balance/weight - confirms positive fluid balance

Management

🥇 First-line

•stop the transfusion immediately - do not slow, stop

•furosemide 40 mg IV - reduces preload; core pharmacological intervention

•supplemental oxygen - target SpO2 >94%

•sit patient upright - reduces venous return immediately

🥈 Second-line

•repeat IV furosemide or escalate diuretic dose if inadequate response; treat as acute decompensated cardiac failure

🥉 Third-line

•non-invasive ventilation (CPAP/BiPAP) for refractory hypoxia; invasive ventilation if fails

⚠️

Do NOT give IV fluids in TACO - the patient is already volume overloaded. IV fluids are indicated in acute haemolytic reaction (hypotensive, needs renal protection). Giving fluids in TACO worsens pulmonary oedema.

TACO vs other transfusion reactions