PNEUMOTHORAX

Question 1

What is a pneumothorax?

Answer 1

A collection of air within the pleural space

Question 2

What are the 2 types of pneumothorax?

Answer 2

Spontaneous - occurring without prior trauma e.g. older patients with underlying lung disease
Traumatic

Question 3

What are the 2 types of spontaneous pneumothorax?

Answer 3

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

Question 4

why do spontaneous pneumothorax often occur in tall thin young men?

Answer 4

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

Question 5

What are pulmonary blebs and bullae?

Answer 5

A small collection of air between the lung and visceral pleura (subplueral)
Blebs - Usually <1cm in diameter
Bullae - usually >1cm diameter

Question 6

Whats the pathophysiology behind a spontaneous pneumothorax?

Answer 6

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

Question 7

What are the clinical features of pneumothorax?

Answer 7

sudden onset unilateral pleuritic chest pain and dyspnoea
Tracheal deviation
Reduced chest expansion
Reduces breath sounds
Hyperresonnat percussion
Absent tactile/vocal fremitus

Question 8

How do you diagnose pneumothorax?

Answer 8

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)

Question 9

How can you estimate the size of a spontaneous pneumothorax?

Answer 9

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)

Question 10

How do you manage a primary spontaneous pneumothorax that has a rim of air >2cm or symptomatic?

Answer 10

Needle aspiration (14-16G) - take 2.5L

Refer to respiratory specialists for follow up

Question 11

How do you manage a primary spontaneous pneumothorax that has a rim of air <2cm and asymptomatic?

Answer 11

Observation with outpatient follow up
Advise pt to return if they develop dyspnoea
Refer to respiratory specialists for follow up

Question 12

How do you manage a secondary spontaneous pnuemothoax?

Answer 12

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

Question 13

When managing a pneumothorax, what should you do if aspiration fails twice?

Answer 13

Chest drain is required

Question 14

What are risk factors for a pneumothorax?

Answer 14

Pre-existing lung disease
Connective tissue diseases e.g. Marfans
Tall, thing, young man
Smoking
Medical procedure e.g. lung biopsy or mechanical ventilation

Question 15

How much does smoking increase the risk of developing a pneumothorax?

Answer 15

the lifetime risk of developing a pneumothorax in healthy smoking men is around 10% compared with around 0.1% in non-smoking men

Question 16

Why is flying contraindicated following a pneumothorax?

Answer 16

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

Question 17

Can you scuba dive following a pneumothorax?

Answer 17

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

Question 18

What is a tension pneumothorax?

Answer 18

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

Question 19

What are the signs of a tension pneumothorax?

Answer 19

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

Question 20

How do you manage a tension pneumothorax?

Answer 20

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

Question 21

What is the triangle of safety?

Answer 21

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

Question 22

Whats important about inserting a chest drain?

Answer 22

Insert into triangle of safety, just above the rib to avoid the neurovcascular bundle
Once inserted, obtain a CXR to check positioning