Transfusion Circulatory Overload (TACO)

Transfusion associated circulatory overload is acute or worsening respiratory compromise or pulmonary oedema, caused by a transfusion volume or rate that exceeds the patient's circulatory capacity, occurring during transfusion or within 12 hours. It is among the commonest causes of transfusion related morbidity and mortality, and it is largely preventable.

Case definition. Acute or worsening respiratory compromise, evidence of pulmonary oedema, or both, with at least three of the following:

• Acute or worsening respiratory distress.

• Tachycardia.

• Raised blood pressure.

• Acute or worsening pulmonary oedema on examination or chest imaging.

• Evidence of positive fluid balance or response to diuretic.

• Raised natriuretic peptide (over 1.5 times the pre-transfusion value).

Clinical features. Dyspnoea, orthopnoea, cough with frothy sputum, hypoxia, hypertension, tachycardia, raised jugular venous pressure, third heart sound and bibasal crepitations. Fever is uncommon, and it can occur with normal blood pressure.

Risk factors. Age over 70 years, heart failure, renal failure, positive fluid balance, chronic severe anaemia (already volume expanded), rapid infusion, large volumes (including plasma), neonates and small children, concurrent intravenous fluids and low serum albumin.

Special groups. Older adults, patients with heart or kidney disease, children with severe anaemia, and patients receiving several components together.

Differential diagnosis. Transfusion related acute lung injury, acute coronary syndrome and cardiogenic pulmonary oedema, anaphylaxis, acute respiratory distress syndrome, sepsis and pulmonary embolism.

Distinguishing circulatory overload from lung injury.

Both can coexist, and when they cannot be separated, the case is reported as both.

Initial assessment. Oxygen saturation and respiratory rate, blood pressure and heart rate, jugular venous pressure, chest examination, fluid balance, electrocardiogram, natriuretic peptide, chest imaging and bedside echocardiography where available.

Immediate actions in order.

1. Stop the transfusion and clamp the line.

2. Assess the patient: airway, breathing and circulation. Sit the patient upright with legs down, and give high flow oxygen.

3. Keep intravenous access with a new giving set and a keep-open infusion only, stopping other intravenous fluids.

4. Recheck identity of patient and unit.

5. Inform the blood bank and the responsible clinician, and return the unit and set.

6. Do not restart the transfusion without authorised clinical evaluation.

Treatment.

• Furosemide 20 to 40 mg intravenously in an adult, with higher doses (40 to 80 mg) in renal impairment, repeated as needed (0.5 to 1 mg/kg in a child). Monitor urine output.

• Non-invasive ventilation or continuous positive airway pressure for respiratory failure.

• Glyceryl trinitrate if hypertensive and with heart failure, and treat arrhythmia and ischaemia.

• Dialysis or ultrafiltration for refractory overload in renal failure.

• Escalate to intensive care if hypoxia persists.

Investigations. Natriuretic peptide (compare with pre-transfusion value if available), chest imaging, echocardiography, electrocardiogram and troponin, arterial blood gas, urea, creatinine and electrolytes, and cultures if fever or hypotension occurs.

Definitive management. Most patients improve within hours of diuresis and oxygen. Monitor fluid balance, weight and renal function, and treat the underlying heart or kidney disease.

If further transfusion is needed. Reassess the need. If still required, give small aliquots slowly (about 1 mL/kg/hour, with each unit over up to 4 hours or split by the blood bank), with a diuretic given when appropriate, in an upright position and with close monitoring.

Reporting. Report to the transfusion service and haemovigilance system, with the case classification and any suspected lung injury component.

Prevention.

1. Assess risk before every transfusion (heart failure, renal failure, positive balance, age, severe chronic anaemia, neonate).

2. Transfuse only when indicated, one unit at a time, with reassessment.

3. Use slow rates in at risk patients (about 1 mL/kg/hour), and avoid rapid infusion unless bleeding.

4. Stop or reduce other intravenous fluids during transfusion and give diuretics only when there is evidence of volume overload.

5. Avoid unnecessary plasma and large volumes.

6. Monitor fluid balance, vital signs and respiratory status during and for 6 to 12 hours after transfusion.