Pulmonary Embolism Flashcards
What is a pulmonary embolism?
https://www.youtube.com/watch?v=Lp65yGitCNo
A venous thrombi, usually from a DVT, passes into the pulmonary ciruclation and blocks flow to the lungs
What are risk factors for PE?
- Trauma
- Hormones - COCP, pregnancy
- Road traffic accidents
- Operations
- Malignancy
- Blood disorder - polycythaemia etc.
- Old age, obesity
- Serious illness
- Immobilisation
- Splenectomy
Others include dehydration and previous DVT
What symptoms might you see in someone with a PE?
Sudden onset
- Dyspnoea - can be severe, and worsened by exertion
- Cough +/- haemoptysis
- Pleuritic chest pain
- Syncope
What is the mechanism behind dyspnoea in thromboembolism?
It is thought that pressure receptors or C-fibres in the pulmonary vasculature or right atrium are activated and interact with central systems, contributing to dyspnoea
Why can haemoptysis occur in PE?
Any condition that results in pulmonary venous hypertension may cause haemoptysis. For example, left ventricular failure can lead to increasingly high pulmonary venous pressures. These high pressures damage venous walls, causing blood excursion into the lung and eventually haemoptysis.
Why might you get raised JVP in PE?
PE may be large enough to create back pressure into the right heart, atrium and venous system, thus resulting in
In a PE, which physiological process occurs (alveolar dead space or shunting) and what would be the V/Q ratio (>1)?
Alveolar dead space - V/Q mismatch >1
Why does tachycardia occur in PE?
Activation of the sympathetic nervous system and/or catecholamine release due to a combination of hypoxia and reduced stroke volume and resultant CO (heart tries to compensate)
Why can those with PE develop a gallop rhythm?
Due to heart failure caused by PE - rapid ventricular against stiff ventricular walls causes the sound
Why would you get a loud P2 in PE?
Increased PHT of any cause causes the pulmonary valve to slam shutand cause a louder than normal P2
Why would you get right ventricular heave in PE?
RHF
Why might you get a pleural rub in PE?
Inflammatory process is triggered by emboli, which spreads into the plerua and causes loss of normal pleural lubrication
What causes tachypnoea in PE?
Compensatory response to either a drop in O2 or a rise in CO2
Why might you get central cyanosis in someone with PE?
A V/Q mismatch or shunting of blood through the lungs, without adequate oxygenation, will increase the quantity of deoxygenated haemoglobin that passes out of the lungs, leading to reduced oxygen saturation
What signs might you see in someone with a a mild PE?
- Tachycardia
- Tachypnoea
- Calf swelling, erythema, oedema, tenderness
- Decreased SpO2
- Pleural Rub
- Decreased breath sounds
- Mild fever
How would you approach investigating someone with a PE?
Decide if non-massive or massive. If non-massive - Wells score, then:
- Confirm diagnosis
- Determine severity
- Look for causes
How would you confirm/Exclude the diagnosis of PE?
- Low Wells score - D-Dimer - if negative exclude
- High Wells score or D-dimer positive - CTPA or V/Q (if CTPA contraindicated)
What investigations would you do when trying to determine the severity of a PE/the effect that it has had?
- Clinical Signs
- Bloods - ABG’s, FBC, U+E’s
- ECG
- CXR
- CTPA
- Echocardiogram
- Bilateral leg Doppler (look for DVTs)
What might you see on ECG in someone with a PE?
- Sinus Tachycardia
- RV strain - T-wave inversion V1 to V4 and inferior leads, RBBB, right axis deviation
- RA enlargement - P pulmonale, RV dilation i.e. dominant R in V1
- S1Q3T3 pattern - rare
What might you see on X-ray in PE?
- Hampton Hump - Wedge infarcts
- Westermarks signs - Regional oligaemia
- Fleischer’s Sign - Enlarged pulmonary artery
- Elevated hemidiaphragm
- Effusions
What are the criteria for the PE Wells Score?
- Clinical signs and symptoms of DVT = +3
- Alternative diagnosis less likely = +3
- HR >100 = +1.5
- Immobilisation (>3/7days) / surgery in the past month = +1.5
- Previous DVT/PE = +1.5
- Haemoptysis = +1
- Cancer - on treatment, past 6 months or palliative = +1
What signs might you see in someone with a severe PE?
- Decreased SpO2
- Tachycardia
- Tachypnoea
- Hypotension
- Raised JVP with prominent a wave
- Gallop rhythm
- Pleural rub
- Loud P2 and splitting of S2
- Tricuspid/pulmonary regurgitation
- Right venticular heave
- Cyanosis