Emergency · Adult · Reference card

Perioperative Anaphylaxis

Resuscitation Council UK algorithm — grading, adrenaline dosing, fluids and follow-up at a glance.

Draft — not yet clinically verified. Adult doses from the RCUK peri-operative anaphylaxis algorithm (Dodd et al, Anaesthesia 2024). This is a memory aid — use your department's QRH / RCUK poster in the event. Paediatric doses follow APLS. "If in doubt, treat."

Immediate — grade 3–4

Recognise · call for help · adrenaline + fluids

Use the Valentine / STOP approach: remove the likely trigger (stop drug, colloid, chlorhexidine, latex), call for help and note the time.
Airway / Breathing: 100% oxygen, secure the airway, hand-ventilate; treat bronchospasm.
Circulation: lay flat / legs up, large-bore access, give adrenaline and a rapid fluid bolus.
If no cardiac output → start CPR and follow ALS with 1 mg IV adrenaline.

RxAdrenaline — adult

IV access, monitored

50 µg IV bolus, titrated

0.5 ml of 1:10,000 (1 mg / 10 ml). Repeat & titrate to effect.

No IV access

500 µg IM (0.5 mg)

0.5 ml of 1:1000. Repeat after 5 min if needed.

Cardiac arrest (grade 4)

1 mg IV + CPR

Follow the ALS algorithm.

Refractory

Low-dose IV infusion

Start if boluses insufficient — peripheral line acceptable; use local protocol.

FlFluids & refractory adjuncts

Crystalloid bolus 500–1000 ml (20 ml/kg in children <12 y), titrated to response — large volumes (60–100 ml/kg) may be needed.
Refractory, on a beta-blocker: consider glucagon.
Refractory vasoplegia: consider vasopressin, noradrenaline or metaraminol alongside the adrenaline infusion.
Bronchospasm: nebulised salbutamol ± ipratropium.
Steroids & antihistamines are NOT recommended for initial treatment — steroids may be an adjunct in refractory shock/bronchospasm only.

GrGrading of the reaction

Grade 1

Mucocutaneous only — erythema, urticaria, angioedema.

Grade 2

Moderate — hypotension, tachycardia, moderate bronchospasm, GI symptoms.

Grade 3

Life-threatening — severe hypotension, cardiac arrhythmia, severe bronchospasm (± skin signs).

Grade 4

Cardiac and/or respiratory arrest.

Skin signs may be absent in severe peri-operative anaphylaxis — cardiovascular collapse can be the first sign.

IxAfter the event — mast cell tryptase

Take three timed samples (do not delay resuscitation to sample):
1 — as soon as feasible once resuscitation is under way.
2 — ideally 1–2 h after the onset of symptoms.
3 — at least 24 h after the event (baseline).
Tryptase half-life is ~2 h and may normalise within 6–8 h — timing is critical.

Interpretation & referral

A significant (dynamic) rise = peak tryptase > 1.2 × baseline + 2 µg/L. A normal tryptase does not exclude anaphylaxis.
Document the reaction and refer to a specialist peri-operative allergy clinic (NAP6 referral network).

Dodd A, et al. Emergency treatment of peri-operative anaphylaxis: Resuscitation Council UK algorithm for anaesthetists. Anaesthesia 2024;79:535–541 (Table 1, Fig 2).