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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.

Acute limb ischaemia

Cardiology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Escalate

Acute limb ischaemia is a vascular emergency. New sensory loss or weakness means an immediately threatened limb: contact a vascular specialist at once, give unfractionated heparin unless contraindicated and transfer for urgent revascularisation.

Synopsis

Identify a suddenly threatened limb, grade viability and start time-critical anticoagulation and vascular treatment without avoidable imaging delay.

  • ALI is a sudden fall in limb perfusion, usually within 14 days, that threatens tissue viability.
  • The six Ps—pain, pallor, pulselessness, perishing cold, paraesthesia and paralysis—describe the syndrome, but an incomplete set does not exclude it.
  • Neurological deficit drives urgency: paraesthesia and especially motor weakness indicate a threatened limb.
  • Rutherford I is viable, IIa marginally threatened, IIb immediately threatened and III irreversible.
  • Call vascular surgery before waiting for routine tests; a IIb limb requires immediate revascularisation planning.
  • Give IV unfractionated heparin promptly unless active bleeding, previous heparin-induced thrombocytopenia or another major contraindication exists.
  • CTA is usual first-line anatomical imaging when it will guide treatment, but imaging must not delay revascularisation of an immediately threatened limb.
  • After reperfusion, actively look for compartment syndrome, hyperkalaemia, acidosis, acute kidney injury and recurrent ischaemia.

Key red flags

Rutherford IIa—marginally threatened

Minimal sensory loss, usually toes, with no motor deficit; salvageable if treated promptly.

Rutherford IIb—immediately threatened

Sensory loss beyond the toes and rest pain, with mild or moderate weakness; arterial Doppler usually absent and urgent revascularisation is mandatory.

Rutherford III—irreversible

Profound anaesthesia, paralysis/rigor and absent arterial and venous Doppler signals suggest non-viable tissue; urgent senior decision about primary amputation or palliation is required.

Investigation priorities

01
Immediate serial neurovascular examination with hand-held DopplerFirst step

Grade limb viability and detect deterioration.

Management branches

first minutesSuspected ALI

Sudden limb pain/coldness, pulse loss, sensory change or weakness.

  1. First: assess ABCs, note exact onset, examine both limbs and document Doppler, sensation and motor power; give analgesia and keep the patient nil by mouth.
  2. Next: contact the on-call vascular specialist immediately and arrange transfer to a centre offering open and endovascular treatment.
  3. Next: give IV unfractionated heparin unless contraindicated; provide IV access, cautious hydration and oxygen only when hypoxaemic.
  4. Escalation: repeat the limb examination during every delay or transfer and report any new sensory or motor deficit at once.

Key medicines

Unfractionated heparin5,000 units IV bolus, or 70–100 units/kg IV, followed by an IV infusion adjusted to APTT or ACT response.Do not give with active major bleeding or previous immune HIT; review recent surgery, intracranial bleeding risk and baseline platelets/coagulation. A non-heparin anticoagulant needs specialist/haematology input if HIT is suspected.
MorphineOne licensed injection regimen uses 2.5–10 mg IV, injected slowly over 4–5 minutes; select the lowest effective dose and titrate any further dosing to response in a monitored setting.Reduce dose in older/frail people and use particular caution in renal or hepatic impairment; monitor consciousness, respiratory rate, oxygenation and BP. Analgesia must not postpone repeated neurological examination.
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Sources and review status5 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • ESVS 2020 Clinical Practice Guidelines on Acute Limb IschaemiaRutherford classification, imaging, heparin and revascularisation.
  • 2024 ESC Guidelines for peripheral arterial and aortic diseasesCurrent European ALI and PAD framework.
  • NICE CG147: Peripheral arterial diseaseUK PAD assessment and limb-threatening disease context.
  • eMC: Heparin sodium injection SmPCContraindications, monitoring and adverse effects.
  • eMC: Morphine sulfate injection SmPCAdult IV dose, administration rate and organ-impairment cautions.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom