Pneumothorax

With a Pneumothorax, there's rupture of one of the pleural membranes, so the intrapleural pressure becomes equal to atmospheric pressure. The opposing forces are then lost, leading to lung collapse. Spontaneous pneumothorax is classified into:

Primary - No underlying lung pathology. Typically occurs in tall, thin, young men.

Secondary - Underlying lung pathology. Causes of it include:

• Connective tissue disease (e.g. marfan’s, ehlers-danlos)

• Obstructive disease (e.g. asthma, COPD)

• Infection (e.g. TB, pneumonia)

• Fibrotic disease (e.g. CF)

• Neoplastic disease (e.g. bronchial ca.)

Traumatic pneumothorax can be classed into:

• Iatrogenic e.g. insertion of central line or positive pressure ventilation

• Non-iatrogenic e.g. penetrating trauma or blunt trauma w/rib fracture

Presentation

• Sudden-onset SOB

• Pleuritic chest pain

O/E - Reduced chest expansion, Hyper-resonant percussion, Reduced/absent breath sounds, Reduced vocal fremitus/resonance

N.B. Air or fluid outside of the lungs decreases the transmission of sound vibrations. Increased tissue density of the lung increases the transmission of sound vibrations.

Investigations

The main investigation to do is an Erect CXR.

• If the pneumothorax is too small to see, a CT Chest can be done

Management

Tension Pneumothorax

With this, a one-way valve is created in which air can enter the pleural space but can’t leave (i.e. is trapped). This progressive air accumulation makes the intrapleural > atmospheric pressure. This causes mediastinal shift and compression of the major vessels, eventually leading to obstructive shock and cardiorespiratory arrest.

Clinical features of this are:

• Haemodynamic instability - tachypnoea, tachycardia, hypotension, raised JVP

• Tracheal deviation to contralateral side

• O/E:

  • Haemodynamic instability - tachypnoea, tachycardia, hypotension, raised JVP

  • Tracheal deviation to contralateral side

  • Reduced chest expansion

  • Hyper-resonant percussion

  • Reduced/absent breath sounds

  • Surgical emphysema

Patients have to be managed with immediate needle decompression with a large-bore cannula inserted in the 2nd intercostal space, midclavicular line. Once pressure is relieved, a chest drain should be inserted (reduces the risk of immediate recurrence).

• If this doesn't work, try decompression in the 4th/5th intercostal space, mid-axillary line

N.B. Insert needle just above rib edge to avoid damage to neurovascular bundle below rib.

N.B. Chest drain inserted into Triangle of Safety (just anterior to mid-axillary line).