16. Pneumothorax Flashcards
What is a pneumothorax?
Presence of air between the visceral and parietal pleura(pleural cavity)
What is the result of air within the pleural cavity?
Disuption of the pleura -> air flows from higher pressure to lower pressure -> disruption of the balance between outward recoil of chest wall and inward recoil of lung -> lung collapses.
What are the 3 ways of classifying pneumothorax?
Simple VS Tension pneumothorax
Primary VS Secondary pneumothorax
Spontaneous VS Iatrogenic VS Traumatic pneumothorax
Where can the air come from in a pneumothorax?
- the lung
- through chest wall
- both
Compare simple and tension pneumothorax
Simple
• Haemodynamic stable patients
Tension
• Causes haemodynamic instability
• Caused by the one-way flow of air. - air accumulates in pleural cavity and not drained out
contrast primary and secondary pneumothorax
Primary
• No underlying lung pathology
• Spontaneous
Secondary
• Underlying lung pathology
What are the risk factors for primary pneumothorax?
- Male
- Young
- Family history of pneumothorax
- Smoking (9x risk)
What are the underlying lung pathologies in secondary pheumothorax?
- COPD (70%)
- Asthma
- Bronchiectasis – inc cystic fibrosis
- Lung cancer
- Infections : TB, pneumonia
- Marfan’s syndrome, Ehler’s Danlos syndrome
- RA
What are the possible causes of pnuemothorax?
- spontaneous
- iatrogenic
- trauma
Describe how spontaneous pnuemothorax occurs?
- spontaneous = primary
* Usually due to subpleural blebs / bulla (air-filled sac) that bursts, allowing air into the pleural cavity
Describe how iatrogenic pnuemothorax occurs?
caused by invasive medical procedures e.g. - central vein cannulation, pleural tap or biopsy, transbronchial biopsy, fine needle aspiration, pacing
Describe how trauma pnuemothorax occurs?
• Severe chest wall injury -> stab wound or gunshot
wound -> allows air to enter the pleural space
• Rib fractures -> puncture the visceral pleura
What do the 3 classifications of pneumothorax tell you?
- Simple VS Tension pneumothorax = ?emergency
- Primary VS Secondary pneumothorax = ?underlying lung disease
- Spontaneous VS Iatrogenic VS Traumatic pneumothorax = aetiology
Describe how pneumothorax can be split?
• simple:
- primary
- secondary
• tension
primary and secondary can develop into tension
Describe the classical presentation of simple pneumothorax
Chest pain - Pleuritic in nature - Sudden onset - Sharp pain +/- SOB History of trauma/lung disease
What are the results of a respiratory examination of a patient with simple pnuemothorax?
• Trachea deviation: normal • Chest movement: Reduced on affected side • Percussion note: Hyper- resonant or resonant on affected side • Breath sounds(Auscultation): reduced /absent on affected side • Vocal/tactile resonance: Reduced on affected side
What is seen on a CXR of simple pneumothorax?
Hyper-lucent (ie appear darker)
Absent lung markings(beyond edge of collapsed lung)
Collpased lung borders seen
What is seen on a CT of simple pneumothorax?
Absent lung markings
Collapsed lung borders seen
What is the treatment for asymptomatic pneumothorax patients?
Usually don’t require treatment, air is absorbed into the blood vessels - conservative treatment
What is the treatment for symptomatic simple pneumothorax patients?
Symptomatic
- and has a small pneumothorax : needle pleural aspiration may be sufficient
- and has a large pneumothorax: insertion of chest drainage.
Where is the safe triangle for chest drainage?
Between lateral borders of Pec major and Lat dorsi, above nipple line
• Superior: Base of the axilla
• inferior: 5th Intercostal space/6th rib
• In the mid-axillary line
• Just above 6th rib, to avoid neurovascular bundle
Describe how the chest drain works?
Connected to underwater seal
- bubbles indicate air being released from pleural space
- bubbles stop = air removed
- under water seal ensures air doesn’t enter pleural space through tube
What is a tension pneumothorax?
can occur due to any aetiology and is defined as any size of pneumothorax causing mediastinal shift and cardiovascular collapse.
Why do tension pnuemothorax occur?
Occurs whenever air can enter the pleural cavity on inspiration, but cannot escape on expiration because of the development of a one-way valve system at the site of the breach in the pleural membrane
What are the effects of tension pneumothorax on lungs and CVS?
- intrapleural pressure increases above atmospheric pressure
- Compresses normal lung
- Venous return impaired, therefore cardiac output drops
- results in hypoxaemia and haemodynamic compromise
What are the presenting symptoms of tension pneumothorax?
• Chest pain - Pleuritic in nature - Sudden onset - Sharp pain • +/- SOB • History of trauma/lung disease \+ • Respiratory distress • Cyanosis • Marked tachycardia • Marked hypoxemia • tachypnoea • hypotension
What are the results of a respiratory examination of a patient with tension pnuemothorax?
• Trachea deviation: Away from the affected side • Chest movement: Reduced on affected side • Breath sounds(Auscultation): reduced /absent on affected side
No time for other test - emergency
but percussion would be hyper-resonant
What is the treatment for tension pneumothorax?
Emergency needle decompression of the chest:
Insert a plastic cannula (Venflon) into the second intercostal space in the mid-clavicular line.
Cannula left in place till chest drain inserted (in the 4th ICS mid axillary line) when patient is
stable
