Traumatic Pneumothorax

Traumatic pneumothorax is air in the pleural space following blunt or penetrating chest trauma, or iatrogenic injury.

• Common in chest trauma (20 to 40% of blunt thoracic trauma; up to 50% of penetrating).
• Mechanisms: rib fracture laceration of lung, shear injury, alveolar rupture from compression, penetrating injury (stab, gunshot), barotrauma with mechanical ventilation, central line placement, thoracentesis, biopsy, acupuncture, scuba diving, blast injury.
• Types: simple, tension, open (sucking chest wound with defect over two thirds of the tracheal diameter), occult (seen only on CT in 20 to 50% of blunt trauma).
• Associated: haemothorax (haemopneumothorax), pulmonary contusion, flail chest, tracheobronchial injury, oesophageal and diaphragm injury.
• Tension pneumothorax is a life threatening emergency.

• Chest pain, dyspnoea, tachypnoea, subcutaneous emphysema, reduced breath sounds, hyperresonance, asymmetric chest rise.
• Open pneumothorax: sucking sound, air movement through chest wall wound.
• Tension: hypotension, tachycardia, jugular venous distension, tracheal deviation (late), cyanosis, cardiac arrest (PEA).
• Persistent air leak or failure to expand suggests tracheobronchial rupture (bronchopleural fistula, "fallen lung" sign).

• Primary survey per ATLS: clinical diagnosis of tension pneumothorax and treat immediately.
• eFAST: absent lung sliding (sensitivity 90 to 95%); chest radiograph (supine films miss up to 30%; deep sulcus sign); CT chest for occult pneumothorax and associated injuries.
• Arterial blood gas, haemoglobin, crossmatch.
• Bronchoscopy for suspected tracheobronchial injury (persistent leak, large leak).
• Check for associated injuries (spine, abdomen, heart).

• Tension pneumothorax: immediate needle decompression (14 gauge, 8 cm, 5th intercostal space anterior axillary line) or finger thoracostomy, then chest tube.
• Open pneumothorax: three sided occlusive dressing (vented chest seal) then tube thoracostomy at a separate site; definitive surgical closure.
• Tube thoracostomy (28 to 32 Fr in haemopneumothorax; smaller 14 Fr acceptable for pure pneumothorax) for symptomatic pneumothoraces, all pneumothoraces requiring positive pressure ventilation or air transport, and those enlarging on serial films.
• Small occult pneumothorax (seen only on CT) in stable, spontaneously breathing patients: observation with serial chest radiographs at 6 and 24 hours is safe; drain if enlarging or before positive pressure ventilation.
• Analgesia (multimodal, serratus or erector spinae block, epidural), pulmonary toilet, incentive spirometry.
• Prophylactic antibiotics for chest tubes in penetrating trauma (cefazolin 2 g single dose, no more than 24 hours).
• Thoracotomy/VATS for persistent air leak over 5 to 7 days, tracheobronchial injury (primary repair), massive air leak, or retained haemothorax.
• Remove chest drain when air leak stops, lung expanded, drainage under 150 to 200 mL per day; clamping not needed.
• Air travel after resolution; follow up chest radiograph.