PNEUMOTHORAX Flashcards
What is a pneumothorax?
A collection of air within the pleural space
What are the 2 types of pneumothorax?
Spontaneous - occurring without prior trauma e.g. older patients with underlying lung disease
Traumatic
What are the 2 types of spontaneous pneumothorax?
Primary - occurs spontaneously in a previously non-pathological lung - seen in tall, thin young men
Secondary - occurs in previously diseased lungs e.g. COPD and asthma
why do spontaneous pneumothorax often occur in tall thin young men?
Tall thin young men have rapid growth of type chest during growth spits which makes them more at risk to have blebs/Bullae which put you at risk
They may also have a larger thoracic volume relative to their lung volume which can result in increased negative pressure within the chest cavity during inspiration which can increase risk of lung collapse
What are pulmonary blebs and bullae?
A small collection of air between the lung and visceral pleura (subplueral)
Blebs - Usually <1cm in diameter
Bullae - usually >1cm diameter
Whats the pathophysiology behind a spontaneous pneumothorax?
Sudden rupture of a bleb or bullae on the surface of the lung, allowing air to escape into the pleural space = loss of negative pressure = collapse of the lung
What are the clinical features of pneumothorax?
sudden onset unilateral pleuritic chest pain and dyspnoea
Tracheal deviation
Reduced chest expansion
Reduces breath sounds
Hyperresonnat percussion
Absent tactile/vocal fremitus
How do you diagnose pneumothorax?
Erect CXR
CT chest is considered gold standard Ed but often used less than X-ray (may see small pneumothorax that is too small to see on CXR)
How can you estimate the size of a spontaneous pneumothorax?
Measure cupola distance - apex to innermost point of chest wall
OR
Measure inter-pleural distance - at the level of the hilum draw a line perpendicular to the pleural surface on both sides of the lung
(CT scanning may be used to obtain true, accurate measurements)
How do you manage a primary spontaneous pneumothorax that has a rim of air >2cm or symptomatic?
Needle aspiration (14-16G) - take 2.5L
Refer to respiratory specialists for follow up
How do you manage a primary spontaneous pneumothorax that has a rim of air <2cm and asymptomatic?
Observation with outpatient follow up
Advise pt to return if they develop dyspnoea
Refer to respiratory specialists for follow up
How do you manage a secondary spontaneous pnuemothoax?
Rim of air is >2cm or sympathy - small bore seldinger chest drain
Rim of air is 1-2cm - needle aspiration (14-16G) - take 2.5L
Rim of air is <1cm - admit and observe for 24 hours and consider supplemental oxygen
When managing a pneumothorax, what should you do if aspiration fails twice?
Chest drain is required
What are risk factors for a pneumothorax?
Pre-existing lung disease
Connective tissue diseases e.g. Marfans
Tall, thing, young man
Smoking
Medical procedure e.g. lung biopsy or mechanical ventilation
How much does smoking increase the risk of developing a pneumothorax?
the lifetime risk of developing a pneumothorax in healthy smoking men is around 10% compared with around 0.1% in non-smoking men
Why is flying contraindicated following a pneumothorax?
When you fly, the air pressure inside the cabin of the plane is lower than the air pressure at sea level. This decrease in air pressure can cause the air inside your chest cavity to expand, which can worsen your pneumothorax and make it harder for you to breathe.
Avoid for 1 week post check X-ray
Can you scuba dive following a pneumothorax?
No it should be permenantly avoided unless the pt has undergo bilateral surgical pleurectony and has normal lung function and chest CT scan post-op
What is a tension pneumothorax?
A medical emergency
Trauma to the chest wall creates a ‘one way valve’ system which allows air into the inter-pleural space but does not let it escape. This means during inspiration air is drawn into the pleural space but not out during inspiration
This results in increasing pressures which impairs venous return to the heart, compromising CO
What are the signs of a tension pneumothorax?
Signs of respiratory distress and shock
Tracheal deviation away from side of pneumothorax
Reduced air entry to affected side
Increased resonant to percussion on affected side
Tachycardia
Hypotension
How do you manage a tension pneumothorax?
Dont wait for investigations if you suspect itQ!
Decompression - Insert a large bore cannula into the second intercostal space in the midclavicular line
Once pressure is relived with a cannula, insert a chest drain for definitive management
What is the triangle of safety?
A triangle where its safe to insert a chest drain
The triangle formed by the 5th intercostal space, mix axillary line and anterior axillary line
Whats important about inserting a chest drain?
Insert into triangle of safety, just above the rib to avoid the neurovcascular bundle
Once inserted, obtain a CXR to check positioning
