Pneumothorax Flashcards
What is a pneumothorax?
Pneumothorax occurs when air gets into the pleural space separating the lung from the chest wall.
What are the causes of a pneumothorax?
Spontaneous
Trauma (stabbing)
Iatrogenic such as due to lung biopsy, mechanical ventilation or central line insertion
Lung pathology such as infection, asthma or COPD
What is the clinical investigation for a pneumothorax?
Erect chest X-ray
What will a CXR show in the case os a pneumothoax?
A chest xray will show an area between the lung tissue and the chest wall where there are no lung markings. There will be a line demarcating the edge of the lung where the lung markings ends and the pneumothorax begins.
When is a CT scan used in diagnosing a pneumothorax?
CT thorax can detect a small pneumothorax that is too small to see on a chest xray or be used to accurately assess the size of the pneumothorax.
What is the management of a pneumothorax?
If no SOB and there is a < 2cm rim of air on the chest xray then no treatment required as it will spontaneously resolve. Follow up in 2-4 weeks is recommended.
If SOB and/or there is a > 2cm rim of air on the chest xray then it will require aspiration and reassessment.
If aspiration fails twice it will require a chest drain.
Unstable patients or bilateral or secondary pneumothoraces generally require a chest drain.
What is aspiration?
Where a needle is inserted into the intrapleural space and air is aspirated to achieve re-expansion of the lung.
What is a tension pneumothorax?
Tension pneumothorax is caused by trauma to chest wall that creates a one-way valve that lets air in but not out of the pleural space.
What is a one way valve in a tension pneumothorax?
The one-way valve means that during inspiration air is drawn into the pleural space and during expiration, the air is trapped in the pleural space. Therefore more air keeps getting drawn into the pleural space with each breath and cannot escape. This is dangerous as it creates pressure inside the thorax that will push the mediastinum across, kink the big vessels in the mediastinum and cause cardiorespiratory arrest.
What are the signs of a tension pneumothorax?
Tracheal deviation away from side of pneumothorax
Reduced air entry to affected side
Increased resonant to percussion on affected side
Tachycardia (increased HR)
Hypotension (low BP)
Hypoxia
What is the management of a tension pneumothorax?
The management sentence you need to learn and recite in your exams is: “Insert a large bore cannula into the second intercostal space in the midclavicular line.”
If a tension pneumothorax is suspected do not wait for any investigations. Once the pressure is relieved with a cannula then a chest drain is required for definitive management.
This is needle aspiration.
Where are chest trains inserted into?
Chest drains are inserted into the “triangle of safety”. This triangle is formed by:
The 5th intercostal space
The mid-axillary line
The anterior axillary line
The needle is inserted just above the rib to avoid the neurovascular bundle that runs just below the rib.
Once the chest drain is inserted obtain a chest x-ray to check the positioning.
