Blood Transfusion

Threshold, consent, prescribing & monitoring during transfusion

Transfuse when: Hb <70 symptomatic or <70 in stable adults, <80 in ACS/cardiac disease. Always consent, crossmatch, prescribe properly, monitor at 15 minutes, and consider furosemide in cardiac failure patients.

What to do

1 · Is transfusion indicated?

Hb <70: stable adults. Hb <80: cardiac disease/ACS. Active haemorrhage: transfuse regardless of Hb. Symptoms (SOB, angina, tachycardia) lower the threshold.

2 · Verbal consent

Explain: why needed, risks (TACO, TRALI, haemolytic reaction, rare infection). Document: 'Patient verbally consented to blood transfusion, risks explained.'

3 · Send crossmatch sample

Pink-topped crossmatch tube labelled at the bedside (never pre-labelled). Incorrect patient labelling = most common transfusion error.

4 · Prescribe on transfusion chart

Specify: component (packed red cells), volume/units, rate (2h standard, 4h in cardiac failure), any pre-medication if previous reaction.

5 · Pre-transfusion observations

Baseline BP, HR, Temp, SpO₂ before starting. Check: correct patient wristband vs blood bag vs compatibility form.

6 · Monitor during transfusion

Obs at 15 minutes (most acute reactions occur here), then hourly. Any deterioration: stop transfusion, follow reaction protocol.

Drugs

Drug	Dose	Route	Notes
Furosemide	20–40mg	IV between units	Cardiac failure / renal impairment. Prevents TACO. Not routinely needed in healthy patients.
Chlorphenamine	10mg	IV pre-transfusion	Only if known previous allergic reaction. Not routine pre-medication.

Red flags

Fever + rigors + back pain + haemoglobinuria — stop immediately, haemolytic reaction
Breathlessness + bilateral infiltrates + hypotension — TRALI, stop, supportive care
Breathlessness + hypertension + bilateral infiltrates — TACO, stop, furosemide
All serious reactions: retain blood bag and giving set, report to SHOT + MHRA

Reference: BSH Blood Components Guidelines 2020 / SHOT Annual Report / NICE NG24