EM Command Center / Cardiovascular Emergencies • 3 min read • 3 sections

Acute Peripheral Vascular Emergencies & Limb Ischemia

Evidence-based emergency management of acute arterial and venous peripheral vascular catastrophes. Details the 6 Ps of acute limb ischemia (ALI), the Rutherford classification, distinguishing arterial embolism vs. in situ thrombosis, phlegmasia cerulea dolens vs. alba dolens, emergency systemic heparinization, and vascular surgical revascularization pathways.

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High-Acuity

The 6 Ps of Acute Limb Ischemia:Pain, Pallor, Poikilothermia (cold limb), Pulselessness, Paresthesias (earliest nerve sign), and Paralysis (impending irreversible loss).

Immediate Anticoagulation:IV Unfractionated Heparin 80 units/kg bolus, then 18 units/kg/hr infusion (target aPTT 60-80s) to prevent thrombus propagation.

Rutherford Viability Grading:Category I (Viable) -> Urgent CTA; Category IIa (Marginally threatened) -> Emergent revascularization; Category IIb (Immediately threatened: motor weakness) -> IMMEDIATE OR/revascularization; Category III (Irreversible: complete anesthesia, rigor) -> Primary amputation.

Phlegmasia Cerulea Dolens:Massive iliofemoral DVT causing total venous outflow obstruction, cyanosis, bullae, and arterial compromise; emergent catheter-directed thrombolysis or surgical thrombectomy.

Stat Vascular Surgery Consult:Do not delay vascular surgery mobilization for extensive imaging if sensory or motor deficits are already present.

Bottom-Line Clinical Pearl

Acute limb ischemia has a strict 6-hour golden window before irreversible neuromuscular damage and muscle necrosis occur. Administer therapeutic IV Unfractionated Heparin (80 units/kg bolus, 18 units/kg/hr infusion) IMMEDIATELY upon clinical suspicion before obtaining imaging.

1. The 6 Ps & Rutherford Classification of Acute Limb Ischemia

Nerves are exquisitely sensitive to ischemia (sensory loss within 15-30 minutes, motor weakness within 2-3 hours). Muscle tolerates ischemia for 4-6 hours before irreversible rhabdomyolysis and gangrene develop:

Rutherford Class	Limb Status	Sensory Loss	Muscle Weakness	Arterial Doppler	Venous Doppler	Emergency Pathway
Class I	Viable	None	None	Audible	Audible	IV Heparin; emergent CTA; revascularization within 12-24 hours.
Class IIa	Marginally Threatened	Minimal (toes/fingers) or none	None	Often inaudible	Audible	IV Heparin; emergency catheter-directed thrombolysis (CDT) or surgical thrombectomy.
Class IIb	Immediately Threatened	Rest pain, sensory loss extending beyond digits	Mild to moderate (foot drop / finger weakness)	Inaudible	Audible	SURGICAL EMERGENCY: Direct to OR for surgical Fogarty embolectomy or bypass (< 6h).
Class III	Irreversible	Profound, complete anesthesia	Paralysis, muscle rigor / woody tightness	Inaudible	Inaudible	Revascularization causes fatal reperfusion syndrome / hyperkalemic arrest; primary amputation indicated.

2. Arterial Embolism vs. In Situ Thrombosis

Parameter	Arterial Embolus (80% from Cardiac Source)	Arterial Thrombosis (In Situ Atherosclerosis)
History & Risk Factors	Atrial fibrillation, recent anterior STEMI (LV mural thrombus), mechanical heart valve, endocarditis	Prior peripheral artery disease (claudication), diabetes, smoking, prior vascular bypass graft
Onset of Symptoms	Sudden, dramatic onset (minutes to hours); patient remembers exact minute	Gradual, insidious onset (hours to days); pre-existing collateral vessels temper severity
Contralateral Limb Exam	Normal pulses, warm, normal ABI	Absent pulses, cool, atrophic skin, hair loss, thickened toenails (chronic PAD)
Angiography Appearance	Sharp cutoff with 'meniscus sign'; lack of collaterals	Diffuse irregular atherosclerotic disease with extensive collateral network
Surgical Intervention	Simple surgical Fogarty balloon catheter embolectomy	Bypass grafting, endarterectomy, or catheter-directed thrombolysis

3. Phlegmasia Alba Dolens vs. Phlegmasia Cerulea Dolens

Phlegmasia is a life-and-limb-threatening spectrum of massive deep venous thrombosis:

Syndrome	Pathophysiology	Clinical Presentation	Emergency Management
Phlegmasia Alba Dolens ('Milk Leg')	Extensive DVT of deep femoral veins; collateral superficial venous channels remain patent	Massive painful swelling, pale/white limb ('milky white'), cool skin, preserved arterial pulses	Therapeutic IV Heparin, strict limb elevation, bed rest; prevents progression to cerulea.
Phlegmasia Cerulea Dolens ('Blue Leg')	Complete thrombosis of all deep AND collateral superficial venous drainage of the limb	Severe pain, massive edema, dusky violaceous/cyanotic discoloration, petechiae, bullae, loss of distal arterial pulses due to venous compartment pressure exceeding capillary pressure	SURGICAL EMERGENCY: Massive venous gangrene and shock. Stat IV Heparin + Emergent Catheter-Directed Thrombolysis (CDT) or Surgical Venous Thrombectomy; four-compartment fasciotomy if compartment syndrome.

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