Pneumothorax Flashcards
what is a pneumothorax
air in the pleural space
how is pressure in the pleural space established
Muscle tension of the diaphragm & chest wall – contract and expand thoracic cavity outward
Elastic recoil of the lungs – pull lungs inward
2 forces pull on each other creating a balance
Creates a slight vacuum = -5cm of water
what is the mechanism of a pneumothorax?
Pneumothorax forms when seal of pleural space is punctured = air moves in = pressure in pleural space = 0cm of water
Since negative pleural pressure is lost, the opposing forces do not pull on each other = lungs pull in = COLLAPSE
what is the consequence of lung collapse?
↓ oxygen
↑ carbon dioxide (can’t get released)
what are the 3 types of pneumothorax?
spontaneous
traumatic
tension
what is the mechanism of a spontaneous pneumothorax
Bullae (large air pocket) forms on lung surface and breaks
Form when alveoli develops a small leak
Normally alveoli heal up, but result is a bullae
When breaks creates a hole in visceral pleura
Air goes from airway directly to pleural space
what are the 2 types of spontaneous pneumothorax
primary - absence of underlying condition
secondary - underlying lung disease
what are the risk factors for a primary spontaneous pneumothorax?
smoking, family history, marfan syndrome, homocystinurea, tall young men in 20s
what are the causes for a secondary spontaneous pneumothorax
marfans, CF, emphysema, lung cancer, COPD, pneumonia, TB
what is the mechanism of a traumatic pneumothorax
Trauma rips through parietal pleura
Air can enter from outside directly into pleural space
causes of a traumatic pneumothorax
gunshot or stab wound
mechanism of a tension pneumothorax
Creates a one way valve
Air can enter but cannot leave as flap of tissue doesn’t allow tissue to go the other way
Air can build up, increasing pressure
causes of a tension pneumothorax
similar to spontaneous or traumatic pneumothoraxes
what are the symptoms of a pneumothorax?
SOB, pleuritic chest pain, symptoms develop at rest, reduced breath sounds on affected sounds, hyperresonance, hypoxia
what will the features of a simple pneumothorax be on a CXR
trachea is not deviated. Lung collapse may be visible
what will the features of a tension pneumothorax be on xray
the trachea may be deviated away from the side of the pneumothorax. Lung collapse likely to be more obvious
what additional symptoms will tension pneumothoraxes have?
tracheal deviation
Haemodynamically unstable - Hypotensive, Tachycardic, Elevated respiratory rate
what investigations can be done for pneumothoraxes?
Xray - lung tissue mostly black, air in pleural space is entirely black
CT - not routinely indicated
US - absence of lung sliding
Blood gas - hypoxia, resp alkalosis
what are the complications associated with pneumothoraxes?
compression of mediastinum can lead to increased HR, raised JVP, cardiac arrest
how to treat a standard pneumothorax rim of air<2cm
Consider observation for 4-6 hours and repeat CXR to ensure it is not progressing
Then; discharge on advice – don’t do strenuous exercise – and return if breathless.
Evaluate and re-x-ray at 2 weekly intervals until air is re-absorbed
how to treat a • Primary Pneumothorax - SOB + rim of air >2cm on CXR
If acutely unwell
Aspiration – 2nd intercostal space, mid clavicular line
If unsuccessful repeat
if unsuccessful again consider chest drain
If not haemodynamically unstable = Chest drain
how to treat a Secondary Pneumothorax – SOB + rim of air >2cm on CXR
same as primary pneumothorax, treat underlying cause
how to treat an tension pneumothorax
If suspected aspirate before CXR
Use a large bore cannula with a long needed and, if possible with syringe, filled with saline, to act as a water seal, when entering the pleural space.
You should attempt decompression at the 2nd intercostal space at the mid-clavicular line.
Chest tube placed as soon as possible
If remains at 48 hours or recurrent consider pleurodesis
