Random medical images gallery

wingedscapula

User login

Home | Applied Physiology

Fat / Pulmonary Embolus (PE)

Embolus

  • Abnormal mass of undissolved material that is carried in the bloodstream from one place to another

Components of Emboli

  1. Thrombi or mixtures of thrombi and clot
  2. Fat: long bones,
  3. Atheroma - rupture of aotic plaques with emboli to mesenteric vessels
  4. Tumour cells
  5. Air: cannulae, open neck veins, dialysis
  6. Nitrogen: Caisson's disease
  7. Amniotic fluid: labour
  8. Infective: IE
  9. Foreign material - plastic tubing from broken cannulae

 

  Pulmonary Embolus Fat Embolism Syndrome
Trigger/PDF
  1. Wall
    • Increased ageing
    • Vessel injury (limb injury)
  2. Flow (prolonged stasis)
    • Prolonged bed rest
    • Recent surgery
    • Cardiac failure
  3. Constituents
    • Polycythemia
    • Malignancy
    • Dehydration
    • Coagulopathy - ProteinC/S, ATIII deficiency, Factor V Leiden, Antiphospholipid antibodies, HRT, OCP

 

  1. Local trauma
    • Trauma / long bone fractures
    • Joint reconstruction
  2. Systemic
    • Major burns
    • cardiopulmonary bypass
    • Diabetes
    • Pancreatitis

 
Pathophysiology
  1. Thrombi form in deep veins / right atrium
  2. Propagate
  3. Obstruct pulmonary artery (beyond right ventricular outflow tract)
  4. Produces right ventricular strain
  5. Reduced blood flow to lung produces V/Q mismatch (and increased physiological dead space)
  1. Mechanical theory
    • Damaged vasculature releases fat droplets into circulation
    • Enter pulmonary vascular bed
    • Enter systemic circulation via arterio-venous shunts
    • Impaction of emboli in terminal systemic vascular beds produces local ischaemia and tissue injury
  2. Biochemical theory
    • Stress hormones released (steroids, catecholamines)
    • Activate lipases
    • Lipases hydrolyse circulating lipids into FFAs and glycerol
    • FFAs induce pulmonary damage and increase capillary permeability
Clinical features
  1. Local
    • Painless/painful swelling or tenderness of calf
    • Phlegmasia cerulea dolens - ischaemic cyanotic leg following massive ileo-femoral venous thrombosis
    • Phlegmasia alba dolens - ischaemic cyanotic leg following massive ileo-femoral DVT with arterial spasm
  2. Distal
    • Pulmonary embolism
      1. Tachycardia, tachypnoea
      2. Pleuritic chest pain
      3. Shock (outflow obstruction)
      4. Right ventricular strain
      5. Paradoxial embolisation (through PFO) leading to systemic embolisation
  1. Respiratory insufficiency
    • Tachypnoea, cyanosis - pulmonary vascular occlusion by lipid emboli
  2. Petechial rash
    • Distributed in area of chest, mouth, axilla, conjunctiva - direct embolisation of cutaneous vessels
  3. Cerebral features
    • Encepalopathy / distinct peripheral weakness - microvessel embolisation
  4. Pyrexia, tachycardia, retinopathy, renal impairment
Management
  1. Prevent
    • Early mobilisation
    • Heparin
    • TED stockings
    • Intermittent pneumatic compression (intraoperatively)
    • Transvenous intracaval device - umbrella + wire filters
  2. Treat
    • Resuscitate
    • Investigate
      1. ABG - V/Q mismatch
      2. Plasma D-dimers
        1. FDP from action of plasmin on fibrin clot
        2. Measured by latex agglutin test
        3. Misses 10% of PEs
      3. ECG
        1. Sinus Tachycardia
        2. S1Q3T3
      4. CXR - exclude differentials
      5. VQ scan
      6. Spiral CT
      7. Pulmonary angiography
    • Specific therapy
      1. Thrombolysis - Haemodynamically unstable
      2. Pulmonary embolectomy
      3. Anticoagulation: Heparin + warfarin
  1. Investigations
    • ABG
    • FBC
    • Clotting
    • Electrolytes
    • Urine: Lipiduria
    • CXR: "snow storm" appearance
    • ECG: Tachycardia and RV strain
  2. Respiratory support - Oxygenation, CPAP
  3. Fluid/electrolyte balance
  4. General: DVT prophylaxis, nutritional support

 

Login or register to post comments
© www.surgicalnotes.co.uk 2007 - 2011