Pulmonary Embolism Flashcards
What is a pulmonary embolism?
The blockage of a pulmonary artery by a blood clot, fat, tumour or air
What condition does a pulmonary embolism often follow, and where is this condition found?
DVT - ileo-femoral vein
What factors make up Virchow’s triad?
Venous stasis
Vessel wall damage
Hyper-coagulability
What can cause venous stasis?
Increasing age Obesity Immobility Varicose veins Pregnancy
What can cause vessel wall damage?
Trauma
Previous DVT
Surgery
What can cause hyper-coagulability?
Pregnancy Cancer High oestrogen state IBD Blood transfusion Anti-thrombin, protein C or protein S deficiency Thrombophilia
What are some key words in a history of pulmonary embolism?
Collapses Breathlessness Pleuritic chest pain Tachycardia Tachypnoea Obesity
What are the symptoms of pulmonary embolism?
Acute onset: Pleuritic chest pain, usually unilateral Dyspnoea Sense of apprehension Haemoptysis Collapse
What are signs of pulmonary embolism?
Hypoxaemia Tachycardia Hypotension Cyanosis Crepitation on auscultation Pleural rub Elevated JVP Fever
What are features of a small recurrent pulmonary embolism?
Progressive dyspnoea
Pulmonary hypertension
Right heart failure
What are signs of DVT?
Unilateral leg pain and swelling
Change to skin colour and temperature
Venous distension
What diagnostic criteria is used for pulmonary embolism?
Well’s score
What diagnostic score is likely and unlikely to be a pulmonary embolism?
<4 - unlikely
>4 - likely
What is the diagnostic investigation for pulmonary embolism?
CT pulmonary angiogram
When are D-dimers done in pulmonary embolism investigation?
If Well’s score says PE is unlikely but there is clinical suspicion
What does a positive and negative D-dimer result mean?
Positive (raised levels) - PE very likely so start treatment and then confirm with CTPA
Negative (levels normal) - PE negative, look for other cause
What are signs of haemodynamic instability?
Cardiac arrest
Obstructive shock
Persistent hypotension
What are signs of obstructive shock
SBP<90 End organ hypoperfusion causing: - Altered mental state - Cold and clammy - Oliguria - Increased serum lactate
What result on ECG is suggestive of pulmonary embolism?
RV overload
Or sinus tachycardia
Why is a CT pulmonary angiogram used?
Visualises pulmonary artery obstruction
When is CT pulmonary angiogram contraindicated?
Pregnancy
Contrast allergy
Renal impairment
What investigation is done for diagnosis if CT pulmonary angiogram contraindicated?
V/Q scan (ventilation/perfusion scan)
What are some conditions that present similarly to pulmonary embolism?
Unstable angina MI Congestive heart failure Pneumonia Acute bronchitis Exacerbation of COPD or asthma Pericarditis Cardiac tamponade Pneumothorax
What is the immediate management for pulmonary embolism?
Anticoagulation:
LMWH e.g. dalteparin
Warfarin
What is the management for pulmonary embolism if the patient is haemodynamically unstable (high risk)?
Oxygen Anaglesia IV fluids Primary reperfusion Systemic thrombolysis Vasoactive drugs Anti-coagulation
What is the management for pulmonary embolism if the patient is moderate risk?
Anticoagulation
Monitor closely
Rescue reperfusion if any signs of haemodynamic instability
What is the management for pulmonary embolism if the patient is low risk?
Anticoagulation
What are the contraindications for anticoagulation?
Active bleeding
Recent intracranial haemorrhage
Aortic dissection
Low platelets
What is the treatment for massive pulmonary embolism?
Thrombolysis with tPA (alteplase) or streptokinase
What can happen if pulmonary embolism is not treated, and how?
Right heart failure and cardiac arrest
PE increases pulmonary vasculature resistance
This increases work done by RV
This is compensated by increasing heart rate, until this mechanism is overwhelmed and RV over-distends
RV end-diastolic pressure increased and cardiac output decreased, causing decreased LV preload
MAP decreases and causes hypotension and shock
