Pulmonary embolism Flashcards
Define pulmonary embolism
Occlusion of pulmonary vessels, most commonly by a thrombus that has travelled to the pulmonary vascular system from another site
Explain the aetiology of pulmonary embolism
Other causes of embolus: Amniotic fluid Air Fat Tumour Mycotic
Explain the risk factors of pulmonary embolism
Surgical patients Immobility Obesity OCP Heart failure Malignanc
Summarise the epidemiology of pulmonary embolism
Relatively COMMON (especially in hospitalised patients) Occur in 10-20% of patients with confirmed proximal DVT
Recognise the presenting symptoms of pulmonary embolism
Small- may be ASYMPTOMATIC
Moderate Sudden-onset SOB Cough Haemoptysis Pleuritic chest pain
Large (or proximal) As above and: Severe central pleuritic chest pain Shock Collapse Acute right heart failure Sudden death
Multiple Small Recurrent
Symptoms of pulmonary hypertension
Recognise the signs of pulmonary embolism on physical examination
Small-often no clinical signs. There may be some tachycardia and tachypnoea
Moderate Tachypnoea Tachycardia Pleural rub Low O2 saturation (despite O2 supplementation)
Massive PE Shock Cyanosis Signs of right heart strain Raised JVP Left parasternal heave Accentuated S2 heart sound
Multiple Recurrent PE
Signs of pulmonary hypertension
Signs of right heart failure
Identify appropriate investigations for pulmonary embolism
The Well's Score is used to determine the best investigation for PE Low Probability (Wells 4 or less) - use D-dimer High Probability (Wells > 4) - required imaging (CTPA)
Additional investigations:
Bloods- ABG, thrombophilia screen
ECG
May be normal
May show tachycardia, right axis deviation or RBBB
May show S1Q3T3 pattern
CXR-often NORMAL but helps exclude other diagnoses
Spiral CT Pulmonary Angiogram (right) - FIRST LINE INVESTIGATION
Poor sensitivity for small emboli
VERY sensitive for medium to large emboli
Ventilation-Perfusion (VQ) Scan
Identifies areas of ventilation and perfusion mismatch, which would indicate an area of infarcted lung
Pulmonary Angiography
Invasive
Rarely necessary
Doppler US of Lower Limb - allows assessment of venous thromboembolism
Echocardiography-may show right heart strain
Generate a management plan for pulmonary embolism
Primary Prevention
Compression stockings
Heparin prophylaxis for those at risk
Good mobilisation and adequate hydration
If haemodynamically stable O2 Anticoagulation with heparin or LMWH Switch over to oral warfarin for at least 3 months Maintain INR 2-3 Analgesia
If haemodynamically UNSTABLE (massive PE)
Resuscitate
O2
IV fluids
Thrombolysis with tPA may be considered if cardiac arrest is imminent
Surgical or radiological
Embolectomy
IVC filters - sometimes used for recurrent PEs despite adequate anticoagulation or when anticoagulation is contraindicated
Identify the possible complications of pulmonary embolism
Death
Pulmonary infarction
Pulmonary hypertension
Right heart failure
Summarise the prognosis for patients with pulmonary embolism
30% mortality in those left untreated
8% mortality with treatment
Increased risk of future thromboembolic disease
