Pocket ICU Management

Pulseless Extremity

First Things First (assess & treat for the following)

  • Is extremity irreversible, threatened or viable?
    • Irreversible
      • Cyanotic/blue
      • Absent capillary refill
      • Mottled/marbled
      • Anesthesia/insensate
      • No motor function
      • No arterial or venous Doppler signals in foot
    • Threatened: treat w/ sense of urgency
      • Waxy/white color
      • Slow capillary refill
      • Moderate to severe pain
      • Mildly decreased sensory & motor function
      • Absent arterial Doppler signals in foot
      • Venous Doppler signals present in foot
    • Viable
      • Pale/pallor
      • Normal or mildly slowed capillary refill
      • Cool
      • Minimal or no pain
      • Normal sensory & motor function
  • Is there a palpable pulse or Doppler signal or absent Doppler signals?
    • Palpate pulses in the dorsalis pedis (mid-dorsal foot) & posterior tibial (posterior to medial malleolus) positions.
    • If nonpalpable, interrogate for Doppler signals w/ a continuous wave Doppler.
  • Definitions
    • Claudication: pain, usually in the calf or calves w/ exertion (subsides w/ rest)
    • Rest pain: pain at rest, usually at night & usually over the metatarsal heads or distal foot
    • Tissue loss/gangrene: usually develops in the distal watershed areas or in the immediate site of traumatic injury

History and Physical (assess for the following):

  • Trauma to the extremity, sudden onset vs. long history of claudication, rest pain or tissue loss
  • Embolic: 80% cardiac origin, 20% other arterial sources
    • Cardiac origin of embolic sources: myocardial infarction, arrhythmia, prosthetic heart valve, endocarditis, rheumatic heart disease, cardiomyopathy, right-to-left shunts, intracardiac neoplasm
    • Arterial origin of embolic sources: thrombus on plaque, aneurysm, neoplasm, cervical rib, penetrating trauma
  • Thrombotic: history of underlying atherosclerosis, previous vascular surgery, previous trauma, clotting defects or hypercoagulable state, spontaneous abortions in females
  • Hypovolemia w/ history of peripheral vascular disease: dry mucous membranes, decreased skin turgor, orthostatic BP changes
    • Decrease in systolic pressure 10 mmHg or more or increase in pulse 15 bpm or more
    • Decreased urine output (0.5 ml/kg/hr or less)
  • Meds: anticoagulants (& compliance or appropriate monitoring of levels), estrogens or other prothrombotic agents
  • Thorough head-to-toe pulse exam w/ comparison to contralateral limb (helps localize level of stenosis or occlusion)
  • Obtain ankle-brachial index (ABI) for both lower extremities.
    • Take the highest dorsalis pedis or posterior tibial systolic pressure w/ a BP cuff on the calf divided by the highest brachial artery systolic pressure.
    • Normal ABI >0.9, w/ a difference or change of 0.15 between extremities considered abnormal
  • Examine & note changes in tissue color, temp & neurosensory/motor function.

Diagnostic Tests

  • Lab studies
    • PT/PTT/INR (if pt on anticoagulants or suspected coagulopathy)
    • CBC
      • Assess for thrombocytosis, polycythemia or indicators for possible hypercoagulable states.
    • Coagulation screen
      • Indicated for idiopathic or unknown etiology in a suspected hypercoagulable state
      • Includes protein C, protein S, antithrombin III, anticardiolipin antibodies, resistance to activated protein C, prothrombin gene mutation, heparin-induced antibodies
      • Draw prior to administration of anticoagulants.
    • Renal panel
      • Required if possible need for angiography or IV contrast administration (serum creatinine)
      • Assists in assessing fluid/renal status
        • CPK to assess degree of myonecrosis
  • Noninvasive & radiographic studies
    • ECG
      • Evaluate cardiac rhythm & signs of ischemia.
      • Compare w/ previous studies.
    • Echocardiography
      • If suspicious for cardiogenic source in acute embolic disease
      • Transthoracic (TTE) study initially & obtain transesophageal (TEE) study if visualization inadequate, especially left atrial appendage
      • Bubble study may be helpful in identifying presence of right-to-left shunt (possible path for paradoxical emboli).
    • Segmental studies (noninvasive vascular lab)
      • In cases of chronic claudication or known peripheral vascular disease in viable limbs
      • Helps identify level of occlusion or stenosis
    • Duplex scanning of aorta, iliac & femoral arteries versus CT arteriography
      • Helps identify aneurysms & sources of intra-arterial thrombus/emboli
      • For pts w/out cardiac history or symptoms & w/ normal ECG
    • Arteriography
      • Indicated if echocardiogram is negative
      • Helps localize responsible arterial source of emboli & provides a map of distal arterial circulation

General Management Principles

  • First determine limb viability.
    • Thorough history & physical as previously outlined
    • If limb is irreversibly ischemic, it is an unlikely candidate for embolectomy or other thrombolytic or endovascular procedure.
    • If limb is threatened, proceed w/ urgency.
    • If limb is viable, may be able to follow the above diagnostic regimen
  • Anticoagulation
    • Usually w/ IV unfractionated heparin sodium to achieve systemic anticoagulation
    • Screen pts for contraindications for anticoagulation (GI bleed, intracranial hemorrhage, recent major surgery, heparin antibodies).
    • Used to prevent distal propagation of thrombus & occurrence of additional embolic events

Specific Treatment

  • Thrombolytic therapy
    • Limited to pts in whom the embolic debris is thrombus
    • Tissue plasminogen activator (t-PA) most commonly used
    • These agents do not dissolve atherosclerotic plaque or cholesterol emboli, although it may not be clear prior to therapy whether embolic debris is dissolvable thrombus or atherosclerotic plaque.
  • Interventional percutaneous mgt
    • No prospective studies exist that document the superiority of percutaneous interventional therapy over open surgical therapy for acute emboli.
    • Mechanical thrombectomy devices employ various suction or fragmentation techniques for thrombus removal.
    • Percutaneous transluminal angioplasty (PTA) employs small catheter-based balloons w/ or w/out the combination of stent placement for treatment of select pts w/ limited or focal disease of the iliac arteries (limited use for infrainguinal disease).
  • Surgical mgt
    • Balloon catheter embolectomy after cutdown & exposure of femoral or popliteal arteries is used to quickly remove emboli & restore in-line blood flow to extremity.
    • In vessels w/ underlying atherosclerosis, further therapy may be required.
    • Arterial bypass w/ autogenous vein or prosthetic graft may be required if there is severe underlying disease in affected vessel.
    • Direct endarterectomy & patch angioplasty may be employed to treat a focal atherosclerotic stenosis or occlusion.
    • Four-compartment fasciotomy (anterior, lateral, deep & superficial lower extremity compartments) if indicated for compartment syndrome secondary to prolonged ischemia

Ongoing Assessment

  • What to follow:
    • Carefully examine & document distal extremity blood flow (pulses, Doppler signals, ABI’s).
    • Follow clinical exam & course for symptoms of reperfusion injury (see “Complications” section).
    • Careful & frequent assessment of limb for evidence of compartment syndrome (by clinical exam or individual compartment pressure measurements)
    • Continue or initiate workup for underlying etiology or embolic source if not already initiated.

Complications

  • Irreversibly ischemic limbs
    • Gangrene/severe tissue loss
      • May necessitate limb amputation to a viable level
    • Sepsis/infection
      • Amputation may be required emergently for ascending infection (wet gangrene vs. necrotizing fasciitis vs. sepsis).
  • Reperfusion syndrome/injury
    • Manifestations
      • Abrupt & rapid metabolic acidosis
      • Release of oxygen radicals
      • Hyperkalemia
      • Myoglobinuria
    • Treatment
      • Anticipate acidosis intraoperatively & generously administer fluid & bicarbonate.
      • Administer mannitol as oxygen/hydroxy radical scavenger.
      • Administer fluids, glucose & insulin to drive potassium intracellularly.
      • Maintain high hourly urine output w/ alkalinization of urine (pH >6.5) in early reperfusion period to reduce or prevent myoglobinuria & renal failure.
  • Compartment syndrome
    • Manifestations
      • Neuro findings include pain out of proportion to the initial injury or surgical pain, paresthesias or hypesthesias.
      • Muscular findings include weakness, paralysis, tenderness or pain w/ passive stretching.
      • Vascular findings include diminished or absent distal pulses (but normal pulses do not preclude the presence of compartment syndrome).
      • Occurs when interstitial pressure exceeds capillary perfusion pressure, creating inadequate tissue perfusion
      • Compartment pressures >30-40 mmHg are confirmatory.
    • Treatment
      • Immediate four-compartment fasciotomy

Author

  • Written by Andy C. Chiou, MD
  • Revised by Jason S. Lees, MD

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