Anaemia and blood transfusion in the emergency department

A 78-year-old woman with known ischaemic heart disease arrives pale and breathless after a week of melaena; her haemoglobin is 58 g/L and she has angina on minimal exertion. The registrar wants to transfuse two units rapidly to a target of 100 g/L. Three things are wrong with that plan. Her target should be lower: FOCUS randomised high-cardiovascular-risk hip-fracture patients to a liberal 10 g/dL threshold versus a restrictive strategy (symptoms or haemoglobin below 8 g/dL) and found no benefit of the liberal arm (primary outcome 35.2 versus 34.7 per cent).^[2] She should have one unit, then a recheck before any second unit — TRISS delivered one leukoreduced unit at the trigger.^[3] And rapid transfusion into an elderly cardiac patient invites TACO — the leading cause of reaction-related death, a risk that rises with transfusion speed and volume and with cardiorenal comorbidity.^[8]

Hold that bed — a transfusion above the restrictive threshold is often harm dressed as therapy — and the whole topic turns on four things: the threshold, the pre-transfusion check, the recognition of the reaction, and the massive haemorrhage protocol.^[1]

Definition and classification

Anaemia is an emergency when it is symptomatic or severe — transfusion restores oxygen-carrying capacity, but only the symptomatic or bleeding patient meets a restrictive threshold.^[1]

Anaemia is a haemoglobin below the laboratory reference range for age and sex. It becomes an emergency-department problem when it is symptomatic — dyspnoea, angina, presyncope, or a falling haemoglobin from acute loss — or when it is severe enough to meet a restrictive transfusion trigger. Transfusion is the intravenous infusion of a blood component: red cells to restore oxygen-carrying capacity, plasma for coagulopathy, platelets for thrombocytopenia or platelet dysfunction, cryoprecipitate for hypofibrinogenaemia.^[11]

Transfusion is classified by its urgency. The elective or ward transfusion is a single unit given slowly to a stable patient at a restrictive threshold. The massive transfusion is balanced-ratio product delivery to a bleeding patient, operationalised in the emergency department as activation of the massive haemorrhage protocol.^[5]

References13ShowHide

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