Pulmonary Embolism Flashcards
What characterises a pulmonary embolism?
Where do PEs most commonly originate?
What are the most common cause of PEs?
- Obstruction of a pulmonary artery or one of its branches
- Deep veins of Lower limbs/ Pelvis/ Abdomen
- Blood clots (could be fat, air, amniotic fluid, tumour)
When may fat emboli be seen?
What about air emboli?
Fat- Anything that causes long bone fracture (vehicle accident)
Air- Insertion of central access devices
Fat emboli typically resolve spontaneously, but what may they rarely give rise to?
What symptomatic triad does this consist of?
Fat Embolism Syndrome consists of a triad of symptoms;
- Petechial Rash
- Decreased level of consciousness
- Shortness of Breath
Amniotic fluid embolism is a rare complication of pregnancy.
How does it present?
- Sudden maternal collapse (reduced consciousness at any stage in pregnancy and up to 6 weeks after delivery)
- Associated with hypoxaemia, hypotension and DIC
Why does an Amniotic Fluid Embolism occur?
When do most cases occur?
When amniotic fluid/ hair/ fetal cells/ other debris enter maternal circulation
During labour/ immediately after delivery
List 7 risk factors (Same as for a DVT)
Abnormality in vessel wall, blood flow and blood components- Virchow’s Triad
- Smoking
- Immobility
- Post op
- Post Partum/ Pregnancy
- Burns
- Oral contraceptives
- Metastases
What are 3 consequences of a Pulmonary Embolism?
- V/Q Mismatch-> Hypoxaemia
- RV failure and drop in Cardiac Output, due to Increased Pulmonary Artery Pressure
- Possible infarction of portly perfused part of lung (doesn’t usually happen as Bronchial Arteries supply oxygen to compensate)
The presentation of a Pulmonary Embolism can range from Asymptomatic to Cardiogenic Shock.
List 3 symptoms and 2 signs
Signs- Tachypnoea and Tachycardia
Symptoms;
- Pleuritic chest pain
- Coughing
- Dyspnea
(Less common: Haemoptysis, Syncope, Substernal chest pain, Unilateral leg pain, Fever, Chest wall tenderness)
How is a Pulmonary Embolism confirmed?
How would a PE show on an ABG analysis?
Detection of an embolism in CT Pulmonary Angiography (CTPA)
Respiratory alkalosis with;
- Low pO2
- Low pCO2
- Elevated pH
How can a D-Dimer test be used in diagnosing a Pulmonary Embolism?
Can rule out Pulmonary Embolism if test is negative in LOW RISK patients
A rarer form of blood based thrombosis that causes Pulmonary Embolism is Upper Extremity DVT.
What is this?
What are 3 causes?
Acute thrombosis of a brachial/ axial/ subclavian
- Effort induced thrombosis, triggered by repetitive strenuous activity of upper extremities
- Thoracic outlet syndrome
- Foreign object in veins
What is the main cause of death in Pulmonary Embolism?
Acute right sided heart failure leading to;
- Cardiogenic shock with circulatory failure
- Cardiac arrest secondary to arrhythmias
(In 1/3 of patients Left to Right shunting through Foramen Ovale is present)
What are two decision tools that can be used to assess probability of Pulmonary Embolism?
What do NICE guidelines recommend using?
- Original Wells score
- Modified Wells score
- Two level/ two tier Wells score
How many points on the Two Tier Wells Score suggest a Pulmonary Embolism?
0-4 points: PE Unlikely
>4 points: PE Likely
List 7 diagnostic tests for Pulmonary Embolism
- D Dimer levels (Rules out PE if negative in low risk patient)
- Two Tier Wells Score (<4 points rules out PE)
- CTPA
- ABG analysis (Low O2 and CO2, Raised pH)
- FBC (May reveal leucocytosis)
- ECG
- CXR
