Pneumothorax Flashcards
Define pneumothorax and tension pneumothorax
Air enters and accumulates in the pleural space (between visceral and parietal pleura)
Tension pneumothorax = Medical emergency
Intraplerual pressure exceeds atmospheric pressure → accumulation of pressure → lung compression → hypoxaemia and respiratory failure
What is the difference between primary and secondary pneumothorax
Primary pneumothorax: Occurs without clinically apparent pulmonary disease
Secondary pneumothorax: occurs as a complication of an underlying pulmonary disease e.g. COPD, asthma, thoracic endometriosis
What is the aetiology of pneumothorax
Often spontaneous due to a sub-pleural bulla
Normally alveolar pressure is greater than intrapleural pressure (less than atmospheric), so if there is communication between an alveolus and pleural space, gases will follow the pressure gradient into the pleural space.
Trauma
Iatrogenic (subclavian CVP line insertion, pleural aspiration/biopsy, transbronchial biopsy, liver biopsy)
Neonates: air from the overdistended alveoli (RDS) may track into the interstitium → pulmonary interstitial emphysema → Air may leak into the pleural cavity and cause a pneumothorax → Oxygen requirement increases
What are the risk factors for pneumothorax
Smoking
Male sex
Tall and slender
Family history of pneumothorax
Young age, <40 (primary), >55 (secondary)
Recent invasive medical procedures
Chest trauma
Underlying lung disease: Severe asthma | COPD | TB | CF
Carcinoma
Sarcoidosis
Marfan’s, Ehler’s Danlos
Neonatal: Meconium aspiration, ARDS, complication of mechanical ventilation
What is the epidemiology of pneumothorax in children
Occurs spontaneously in up to 2% of deliveries
What are the symptoms and signs of pneumothorax
Asymptomatic
Dyspnoea (sudden)
Pleuritic chest pain (sudden)
Shoulder tip pain
Obs: hypoxia
Resp:
- Ipsilateral reduced breath sounds
- ipsilateral hyperinflation of hemithorax → reduced expansion
- Hyper-resonance on percussion
- Tracheal deviation (tension) AWAY from affected side
- Transillumination with a bright fibre-optic light source (neonates)
What investigations should be done for a pneumothorax
Bloods:
- Blood gas (resp. alkalosis → acidosis), hypoxaemia, hypocapnia
- D-dimer: elevated >500
- FBC
- Clotting screen (correction before insertion of a chest drain)
Other
- CXR: area devoid of obvious lung markings/visible rim between lung margin and chest wall
- US: absence of lung sliding, “A line”, “lung point”, barcode sign”
- CT: visible visceral pleural line, atelectasis or lung hyperexpansion
What is the management for primary pneumothorax
SOB and/or rim of air >2cm on CXR:
- Needle aspiration using 16-18G cannula
- Repeat CXR to see if rim is <2cm
- If not -> chest drain insertion
Air <2cm on CXR
- Discharge + OPD review
What is the management for secondary pneumothorax
SOB and/or rim of air >2cm on CXR →Chest drain insertion
Rim <1cm →high flow oxygen and admit
Rim of air 1-2cm on CXR
1. Aspirate <2.5L using 16-18G cannula
2. Repeat CXR
3. Rim >1cm →chest drain insertion + oxygen + admit
4. Rim <1cm →high flow oxygen and admit
What is the management for tension pneumothorax
Call cardiac arrest team
Insert large bore (14-16G) needle with a syringe partially filled with 0.99% saline into the 2nd ICS in the MCL on the suspected side
Remove the plunger to allow trapped air to bubble through the syringe until a chest drain can be placed
OR
Insert large bore Venflon in the same location
What are the indications for surgery for pneumothorax
Bilateral pneumothorax
Lung fails to expand within 48h of the drain
Persistent air leak
2 or more previous events on the same side
History on the other side
What are the complications of pneumothorax
Re-expansion pulmonary oedema
Talc pleurodesis-related ARDS
Tension: great vein compression → cardiorespiratory arrest
What is the prognosis for pneumothorax
Primary: higher risk of recurrence (30-50% ipsilateral), higher risk of contralateral primary spontaneous pneumothorax
Secondary: greater risk of recurrence, typically secondary spontaneous pneumothoraces
