Pulmonary Embolism (PE)

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CLINICAL DESCRIPTION

Pulmonary Embolism often results from thrombi from the deep veins of the lower limbs or pelvis, which are transported via the right heart into the pulmonary vasculature.

Large emboli may cause obstruction to blood flow and result in life-threatening hypoxia, hypotension and high mortality.

PE should therefore be managed as a medical emergency. 

The risk factors and management for PE are similar to those for DVT.  (See section on ‘DVT’ above). 

CLINICAL FEATURES

 SIGNS AND SYMPTOMS

  • Sudden pleuritic chest pain
  • Shortness of breath (dyspnea)
  • Cough
  • Haemoptysis (due to pulmonary infarction)
  • Syncope (if massive PE)
  • Tachycardia
  • Tachypnea
  • Low oxygen saturation and low blood pressure (if massive pe)
  • Clear chest or signs of pleural effusion/pleural rub
  • DVT signs (tender calf or unilateral leg swelling.

 

Calculate Well’s scoring for PE probability (clinical likelihood)

  • Symptoms of DVT (3 points)
  • No alternative diagnosis better explains the illness (3 points)
  • Tachycardia with pulse > 100 (1.5 points
  • Immobilization (≥ 3 days) or surgery in the previous 4 weeks (1.5 points)
  • Prior history of DVT or pulmonary embolism (1.5 points)
  • Presence of hemoptysis (1 point)
  • Presence of malignancy (1 point)

Well’s Score Interpretation for PE 

Score > 6: High probability 

Score >= 2 and <= 6: Moderate probability 

Score < 2: Low Probability Low probability: D-Dimer test is recommended (if available). 

Moderate or High Probability: D-Dimer test with additional CT Pulmonary angiogram is recommended.

INVESTIGATIONS

  • Full blood count and urea and creatinine
  • D-dimer: high 
  • Chest X-ray: normal or may show area of oligaemia (loss of vascular markings), peripheral wedge-shaped opacity, small pleural effusion, plate atelectasis (linear opacity-atelectasis)
  • ECG: sinus tachycardia (common finding), S1Q3T3 patter
  • Echocardiogram: may see thrombus in pulmonary trunk and strained right heart in Massive PE
  • Compression or Doppler USS of the swollen leg: DVT presence
  • CT Pulmonary angiogram: confirms PE

  TREATMENT

Treatment objectives 

  • To stabilize cardio-respiratory function
  • To prevent further clot formation and embolization
  • To prevent recurrence and development of pulmonary hypertension

NON-PHARMACOLOGICAL

  • Elevate affected leg on a pillow if DVT present
  • Apply compression stockings - after pain subsides if DVT present

PHARMACOLOGICAL 

  • Clinical suspicion of pulmonary embolus/confirmed
    • Oxygen therapy by face mask or nasal prongs or via non-rebreather mask (keep oxygen saturation > 95%).
    • Anticoagulation (as in DVT section above) and aim INR target 2 to 3 when patient on warfarin
    • When target INR is achieved continue warfarin and stop low molecular weight heparin. Maintenance Warfarin dose of 2.5 mg to 5 mg (some may require higher dose to maintain target INR.
    • Anti-coagulate for a minimum of 3 months and then reevaluate if  PE still present and need to continue anticoagulation

Note: Recurrent embolisms and permanent risk factors such as thrombophilia, chronic thromboembolic pulmonary hypertension requires long term anticoagulation.

COMPLICATIONS OF PULMONARY EMBOLISM

  • Obstructive shock (severe hypotension)
  • Hypoxia
  • Chronic thromboembolic pulmonary hypertension (CTEPH)

REFERRAL CRITERIA:

  • Refer all patients with suspected pulmonary embolism, where facilities are unavailable for confirmation of PE
  • PE requires a physician specialist or cardiologist expert management after stabilization.
  • Massive PE can cause Obstructive Shock (systolic BP <90mmHg) which needs thrombolysis under specialist car