Pulmonary Embolism

Question 1

Always suspect PE in sudden collapse ____ weeks after surgery?

Answer 1

1-2 weeks after surgery

Question 2

mechanism of PE

Answer 2

venous thrombi, usually from DVT, pass into the pulmonary circulation and block blood flow to lungs. the source is often occult

Question 3

risk factors of PE

Answer 3

malignancy!! myeloproliferative disorder, antiphospholipid syndrome

surgery - esp pelvic and lower limb

Immobility; active inflammation

Pregnancy; combined OCP; HRT

Previous thromboembolism and inherited thrombophilia

Question 4

Signs and symptoms of a PE

Answer 4

• Acute dyspnoea, pleuritic chest pain, haemoptysis and syncope
• Hypotension, tachycardia, gallop rhythm, increased JVP, loud P2, right ventricular heave, pleural rub, tachypnoea, cyanosis, AF

with thromboprophylaxic, PE following surgery is far less common, but PE may occur after any period of immobility, or with no predisposing factors

Breathlessness may be the only sign

Question 5

Multiple small emboli may present how?

Answer 5

less dramatically with pleuritic pain, haemoptysis, and gradually increasing breathlessness

Look for a source of emboli - especially DVT (is leg swollen)

Question 6

What scoring system do you use for suspected PE?

Answer 6

2-level Wells’ score

Question 7

Investigations for PE

Answer 7

2-level Wells’ score

U&E, FBC, baseline clotting

ECG: commonly normal or sinus tachycardia; right ventricular strain patter V1-V3, right axis deviation, RBBB, AF, may be deep S waves in I, Q waves in III, inverted T waves in III

CXR: often normal, decreased vascular markings, small pleural effusion. Wedge shaped area of infarction. Atelectasis

ABG: hyperventilation + poor gas exchange: low oxygen, low CO2, high pH

Serum D-dimer: low specificity (high in thrombosis, inflammation, post-op, infection, malignancy)

CT pulmonary angiogram (CTPAP): is sensitive and specific and is the test of choice for high risk patients or low risk patients with a +ve D-dimer. If unavailable, a ventilation-perfusion (v/q) scan can aid diagnosis but frequently produces equivocal results

Question 8

Management of PE

Answer 8

Most PE deaths occur within 1 hour - so start treatment fast

Commence LMWH or fondaparinux

If there is haemodynamic instability, consider thromolysis (or high troponin)

Long term anticoagulation: either DOAC or warfarin

IF there an underlying cause, eg thrombophilia, SLE, or polycthaemia? consider malignancy

If obvious remedial cause, 3 months of anticoagulation may be enough, otherwise 3-6 months (long term if recurrent emboli, or underlying malignancy)

Question 9

Immediate treatment of a large pulmonary embolism

Answer 9

Oxygen if hypoxic, 10-15L/min

Morphine 5-10mg IV with anti-emetic if the patient is in pain or very distressed

IV access and start LMWH/fondaparinux

If low BP, give 500mL IV fluid bolus, get ICU input

If haemodynamically unstable - consider thrombolysis. If not - but persistent low BP, consider vasopressors eg dobutamine.

Initiate long-term anticoagulation for all

Question 10

D-dimer test for PE

Answer 10

d-Dimer is formed when cross-linked fibrin is broken down

• ve: can be reassured no PE
  +ve: may not be PE, could be MI etc