Pulmonary Embolism Flashcards
Definition of Pulmonary Embolism
A pulmonary embolism (PE) is an obstruction of the pulmonary vessels caused by:
- Blood clots
- Fat embolism from broken bone
- Amniotic fluid during pregnancy
- Air embolism
4 causes of Pulmonary Embolism
- Blood clots
- Fat embolism from broken bone
- Amniotic fluid during pregnancy
- Air embolism
4 types of Pulmonary Embolism
- Multiple small pulmonary emboli
- Segmental emboli with pulmonary infarction
- Major pulmonary emboli obstruction of the larger branches of the pulmonary tree
- Massive pulmonary embolism
Multiple Small Pulmonary Emboli:
characterised by progressive breathlessness, more commonly identified at outpatient’s appointment
Segmental Emboli with Pulmonary Infarction:
may present with pleuritic pain and/ or haemoptysis, but with little/ no cardiovascular compromise
Major pulmonary emboli obstruction of the larger branches of the pulmonary tree:
may present with sudden onset of SOB, with transient rise in pulse and/ or fell in blood pressure. Often a precursor to a massive PE
Massive pulmonary embolism:
often presenting with loss of consciousness (LOC), tachypnoea and distended jugular vein – may prove fatal (within 1 hour)
Pathophysiology of PE: Haemostasis (blood clotting)
- Vasoconstriction- damage to endothelium cause constriction, reducing the amount of blood flow to the area, limiting blood loss
- Formation of platelet plug- exposed collagen fibres are coated with Von Willebrand Factor (VWF) which attracts and activates platelets. They degranulate and release: ADP (adenosine diphosphate), Serotonin and Thromboxane-A2 (TXA2). These mediators stimulate vasoconstriction and platelet aggregation. PRIMARY HAEMOSTASIS.
- Coagulation – once platelet plug forms, clotting factors begin to form blood clot around plug. Prothrombin & fibrinogen moves to site and becomes activated.
a. Prothrombin + Prothrombinase = Thrombin
b. Fibrinogen + Thrombin = Fibrin
Fibrin adhere to the platelet plug to form insoluble clot
Pathophysiology of PE: Deep Vein Thrombosis
- DVT is a blood clot in a deep vein of an extremity (usually legs)
- Most commonly found in posterior tibial, peroneal, femoral and popliteal veins.
- Most commonly due to impaired venous return (e.g. immobilisation), endothelial injury (e.g. leg fractures) and hypercoagulopathy. This is also known as the Virchows Triad.
Pathophysiology of PE:
- Once a DVT has formed it can dislodge and travel up th venous system, through the right side of the heart, where it can lodge in the pulmonary arteries.
- Here it either partially or completely occludes one or more vessels
- If large Emboli occlude pulmonary vessels, RV pressure will increase, which may lead to Acute RVF, cardiogenic shock and cardiac arrest.
Signs and Symptoms of PE
- Dyspnoea
- Pleuritic chest pain
- Substernal chest pain
- Anxiety
- Cough
- Tachycardia
- Tachypnoea
- Syncope
- Signs of DVT – red, warm, swollen, tender calves
- Haemoptysis
- Hypoxaemia (SpO2 <92%)
- Wells Criteria – above 2
Risk factors for PE
- Recent surgery – abdo, pelvis, orthopaedic
- Varicose veins
- Lower limb fractures
- Immobility
- Pregnancy
- Previous PE/DVT
- Malignant disease
- Oral contraceptives
Differentials to consider for PE
- Pleurisy
- Pneumonia
- Pneumothorax
- Cardiac chest pain
Assessment for PE
DRA(c)BCDE
DANGER assessment for PE
- Assess for any potential dangers
- Manage any bleeds
