44. Pneumothorax

What is pneumothorax

Collection nof air within the pleural space between lung + chest wall

What are the consequences of pneumothorax

Loss of negative pressure bw the 2 membranes → partial or complete pulmonary collapse

What are the classifications of pneumothoraz

• spontaneous

• traumatic

• tension

What is spontaneous pneumothorax

• primary-in patiets with no underlying lung disease

• Secondary- as complication of underlying lung disease

What is traumatic pneumothorax

caused by trauma- penetrating injury, iatrogenic trauma

What is tension pneumothorax

• life threatening

• progressively increasing pressure within chest and cardiorespiratory compromise

• any type of pneumothorax can progress to tension

What is the cause of primary spontaneous PTx

• idiopathic, simple

• subpleural apical blebs

• Risk factor → family history, male, young age, slim + tall, smoking

What is the cause of secondary PTX

• COPD → rupture of bullae in emphysema

• pulmonaryy TB, pneumocystis pneumonia

• CF, Marfan syndrome

• Malignancy

What is the cause of traumatic pneumothorax

• blunt trauma- rib fracture, motor vehicle accident

• penetrating injury- stab, gunshot

• iatrogenic pneumothorax → mechanical ventilation, thoracocentesis, bronchoscopy, lung biopsy

What is the pathophysiolgy of PTX

Increased intrapleural pressure → alveolar collapse → decreased V/Q ratio + increased right to left shunting

What is the pathophysiolgy of spontaneous PTX

• rupture of blebs/ bullae → air moves to pleural space + increasing positive pessure

• ipsilateral lung is compressed and collapses

What is the pathophysiolgy of traumatic PTX

Closed- air enters through hole in lung- blunt

Open- air enters through lesion in chest wall- penetrating

What is the pathophysiolgy of tension PTX

1. Disrupted visceral pleura, parietal pleura, or tracheobronchial tree

2. 1 way valve mechanism- air enters pleural space on inspiration but cannot exit

3. Progressive accumulation of air + increasing positive pressure

4. Collapse of ipsilateral lung + compression of contralateral lung, trachea, heart, SVC

5. Impaired respiratory function, decreased venous return to heart

6. Decreased CO

7. hypoxia and haemodynamic instability

What are the clinical features of PTX

• sudden, severe, stabbing, ipsilateral pleuritic chest pain 

• dyspnoea

• decreased or absent breath sounds

• hyperresonant percussion

• decreased fremitus

• subcutaneous emphysema

What are additional clinical features of tension PTX

• distended neck veins

• haemodynamic instability- tachycardia, HT, pulsus paradoxus

• Severe acute respiratory distress → cyanosis, restlessness, sweating

How do you diagnose PTX

• chest x ray

• chest CT

• ultrasound

What are the findings on a CXR

• pleural line with reduced/ absent lung markings

• deep sulcus sign

• Tension PTX

  • diaphragmatic flattening on ipsilateral side

  • tracheal deviation + mediastinal shift towards contralateral side

What is the treatment of PTX

• respiratory support

  • upright position

  • high flow oxygen

  • if patient needs mechanical ventilation, emergency chest tube placement

  • positive pressure ventilation can turn into simple PTX into life threatening PTX

What is the treatment of spontaneous PTX

• unstable- high risk

  • suspected tension PTX → emergencyneedle thoracostomy

  • Bilateral PTX → emergency chest tube placement

• Stable (low risk): (primary spontaneous PTX)

  • Apex-to-cupola distance <3cm → usually resolves spontaneously

  • Apex-to-cupola distance >3cm → chest tube placement

• Stable (higher risk): (secondary spontaneous PTX)

  • Apex-to-cupola distance <3cm → chest tube placement

  • Apex-to-cupola distance >3cm → same or thoracic surgery consultation

What are the procedures used against PTX

• needle thoracostomy

• finger thoracostomy

• chest tube placement

What is the needle thoracostomy

• In tension PTX

• Immediate insetion of large bore needle

• 2nd intercostal space at midclavicular line or the 4-5th intercostal space between anterior and midaxillary line

• followed by insertion of chest tube

What is a finger thoracostomy

Inicated in tension PTX- unsuccessful needle decompression

• Initial is the same as chest tube- incised + bluntly dissected down to parietal pleura

• Gloved finger is inserted into pleural space to create an open PTX

• no chest tube is inserted or secured

What is a chest tube placement

• insertion of flexible tube into thoracic cavity to drain air or fluid + help lung re expansion

• 4-5th intercostal space between anterior and midaxillary line

• always check CXR after the procedure