Pneumothorax

Question 1

What is a pneumothorax?

Answer 1

When air gets into the pleural space separating the lung from the chest wall

Question 2

How can a pneumothorax occur?

Answer 2

Can be of a spontaneous or traumatic nature

Question 3

How can spontaneous pneumothorax’ be further classified?

Answer 3

Primary
Secondary

Secondary causes include:

• Connective tissue disease (such as Marfan’s syndrome and Ehlers-Danlos syndrome)
• Obstructive lung disease (such as asthma and COPD)
• Infective lung disease (such as TB and pneumonia),
• Fibrotic lung disease (such as cystic fibrosis and idiopathic pulmonary fibrosis)
• Neoplastic disease (such as bronchial carcinoma).

Question 4

How can traumatic pneumothorax’ be further classified?

Answer 4

Iatrogenic causes (such as insertion of a central line or positive pressure ventilation)
Non-iatrogenic causes (either a penetrating trauma or blunt trauma with rib fracture).

Question 5

What happens to lung compliance in a pneumothorax?

Answer 5

When a subpleural bleb ruptures, the intrapleural pressure is equal to the atmospheric pressure. The opposing forces are lost, hence the lungs collapse and the chest wall springs out. Compliance decreases.

Question 6

Presentation

Answer 6

Sudden
Sharp chest pain on inspiration
SOB
Tall thin young man
Might have underlying lung disease or biopsy history

Question 7

Diagnosis

Answer 7

Chest x-ray

A chest xray will show no lung markings. There will be a line demarcating the edge of the lung where the lung markings ends and the pneumothorax begins.

Question 8

When is a CT scan used in the diagnosis of a pneumothorax?

Answer 8

For a small pneumothorax that is too small to see on a chest xray or be used to accurately assess the size of the pneumothorax

Question 9

Clinical examination

Answer 9

On general inspection the patient may be tachypnoeic, hypoxic, and in respiratory distress.

On examination of the chest:

• Reduced chest wall movement
• Reduced/no chest sounds
• Hyper resonant note on percussion
• Use of accessory muscles

Question 10

Management of primary pneumothorax

Answer 10

If the patient is NOT short of breath AND the pneumothorax is <2 cm on a chest x-ray conservative management is sufficient. The patient can be discharged and reviewed in the outpatient department in 2-4 weeks.

If the patient IS short of breath OR the pneumothorax is >2 cm the pneumothorax should be aspirated with a 16-18G cannula under local anaesthetic. If this is successful the patient can be discharged. If this fails an intercostal drain is necessary (and the patient must be admitted).

Question 11

Management of a secondary pneumothroax

Answer 11

If the patient is NOT short of breath AND the pneumothorax is <1 cm on the chest x-ray they do not require further invasive intervention but should be admitted for observation for 24 hours and administered oxygen as required.

If the patient is NOT short of breath and the pneumothorax is 1-2 cm on the chest x-ray aspiration is required. If this is successful the patient can be admitted for 24 hours of observation. If this is unsuccessful and intercostal drain is necessary.

If the patient IS short of breath OR the pneumothorax is >2 cm on the chest x-ray an intercostal drain is necessary (and the patient should be admitted).

Question 12

General management of a pneumothorax

Answer 12

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.

Question 13

What is a tension pneumothorax?

Answer 13

When trauma to chest wall creates a one-way valve that lets air in but not out of the pleural space.

Therefore more air keeps getting drawn into the pleural space with each breath and cannot escape.

Question 14

Why is the one way valve created by a tension pneumothorax dangerous?

Answer 14

Creates pressure inside the thorax that will push the mediastinum across, kink the big vessels in the mediastinum and cause cardiorespiratory arrest

Question 15

What are the signs of a tension pneumothorax?

Answer 15

Tracheal deviation away from side of pneumothorax
Reduced air entry to affected side
Increased resonant to percussion on affected side
Tachycardia
Hypotension

Question 16

First line management of a tension pneumothroax

Answer 16

Insert a large bore cannula into the second intercostal space in the midclavicular line

Once the pressure is relieved with a cannula then a chest drain is required for definitive management.

Question 17

What are chest drains inserted into?

Answer 17

Chest drains are inserted into the “triangle of safety”. This triangle is formed by:

The 5th intercostal space (or the inferior nipple line)
The mid axillary line (or the lateral edge of the latissimus dorsi)
The anterior axillary line (or the lateral edge of the pectoris major)

Once the chest drain is inserted obtain a chest xray to check the positioning.

Question 18

Where is the chest drain inserted and why?

Answer 18

Just above the rib to avoid the neurovascular bundle that runs just below the rib.

Question 19

How can a pneumothorax impact the V/Q ratio?

Answer 19

Less space for lung expansion
Less ventilation
Lower V/Q ratio

Question 20

What does a pneumothorax tend to enhance?

Answer 20

It enhances pulmonary recoil or collapse, and chest wall expansion away from each other.