• Clinical science

Pneumothorax

Abstract

A pneumothorax develops when air as the result of disease or injury enters the pleural space, resulting in the loss of negative pressure between the two pleural membranes. This loss of negative pressure leads to the partial or complete collapse of the lung. Pneumothorax is classified as spontaneous (e.g., by rupture of a subpleural bleb or diseased lung), traumatic, or iatrogenic. Each type can lead to a tension pneumothorax, which is a life-threatening variant of pneumothorax. Patients with pneumothorax present with sudden-onset dyspnea, ipsilateral chest pain, diminished breath sounds, and hyperresonant percussion on the affected side. A tension pneumothorax additionally presents with distended neck veins, tracheal deviation, and hemodynamic instability. Both should be suspected on clinical evaluation. While a tension pneumothorax requires immediate chest decompression, a chest x-ray may be considered to confirm the diagnosis in a stable patient. Small pneumothoraces may resorb spontaneously, but treatment of larger defects usually requires placement of a chest tube to re-establish the negative pressure within the pleural space.

Epidemiology

References:[1]

Epidemiological data refers to the US, unless otherwise specified.

Definition

References:[1]

Etiology

A tension pneumothorax may occur with any of the above-mentioned etiologies!References:[1]

Pathophysiology

  • Increased intrapleural pressure → alveolar collapse → decreased V/Q ratio and increased right-to-left shunting
  • Spontaneous pneumothorax: rupture of blebs and bullae → air moves into pleural space with increasing positive pressure; ipsilateral lung is compressed and collapses
    • Rim pneumothorax: complete uncoupling of the pleura from the chest wall
    • Apical pneumothorax: apical collection of air
  • Traumatic pneumothorax
  • Tension pneumothorax: disrupted visceral pleura, parietal pleura, or tracheobronchial tree → air enters the pleural space on inspiration but cannot exit; progressive accumulation of air in the pleural space and increasing positive pressure within the chest ; → collapse of ipsilateral lung and compression of contralateral lung, trachea, heart, and superior vena cava → impaired respiratory function, reduced venous return to the heart and reduced cardiac outputhypoxia and hemodynamic instability

Clinical features

Clinical features vary from asymptomatic to cardiopulmonary compromise

  • Sudden, severe, and/or stabbing, ipsilateral pleuritic chest pain and dyspnea
  • Reduced, or absent breath sounds, hyperresonant percussion, decreased fremitus on the ipsilateral side
  • Subcutaneous emphysema
  • Additionally in tension pneumothorax:
    • Severe acute respiratory distress: cyanosis, restlessness, diaphoresis
    • Reduced chest expansion on the ipsilateral side
    • Distended neck veins and hemodynamic instability; (tachycardia, hypotension, pulsus paradoxus)
    • Secondary injuries (e.g., open or closed wounds)

P-THORAX: Pleuritic pain, Tracheal deviation, Hyperresonance, Onset sudden, Reduced breath sounds (and dyspnea), Absent fremitus, X-rays show collapse.References:[1][2]

Diagnostics

General

  • Suspected pneumothorax is confirmed by chest x-ray.
    • Immediate x-ray or an extended focused assessment with sonography for trauma (eFAST) in adults with severe respiratory compromise and children
  • CT may provide detailed information about the underlying cause (e.g., bullae in spontaneous pneumothorax).
  • Tension pneumothorax is primarily a clinical diagnosis and prolonged diagnostic studies should be avoided to initiate immediate treatment.

Diagnostic tests

  • Arterial blood gas analysis (ABG) to detect respiratory acidosis
  • Chest x-ray (confirmatory test)
    • Ideally in two projections (PA and lateral), in supine and upright position
    • Chest x-rays are often performed in expiration because it is believed that this allows better detection of small pneumothoraces.
      • Ipsilateral pleural line with reduced/absent lung markings
      • Sudden change in radiolucency
      • Deep sulcus sign: dark and deep costophrenic angle on the affected side
      • If pulmonary disease is present: airway or parenchymal lesions
      • Additional features in tension pneumothorax:
        • Ipsilateral diaphragmatic flattening/inversion and widened intercostal spaces
        • Tracheal deviation towards the contralateral side

,

  • CT: In stable adults without severe respiratory compromise and responsive to resuscitation. Other indications:
    • Presurgical workup
    • Suspected underlying lung disease, to determine the likelihood of recurrent disease
    • Uncertain diagnosis despite chest x-ray

  • ECG: for all patients with anterior chest trauma
    • Reduced QRS amplitude in leads V2–V6 in left-sided pneumothorax
    • Increased QRS amplitude in leads V5–V6 in right-sided pneumothorax
    • ST elevation or depression

A negative eFAST does not exclude a pneumothorax!

In cases of tension pneumothorax, immediate decompression is a priority and should not be delayed by imaging!References:[1][3]

Differential diagnoses

The differential diagnoses listed here are not exhaustive.

Treatment

Approach

  • Simple pneumothorax
    • If small (≤ 2 to 3 cm between the lung and chest wall on a chest x-ray) and asymptomatic
      • Usually resolve spontaneously within a few days (∼ 10 days)
      • Supplemental oxygen (4-6 L/min) via nasal cannula or mask with reservoir
      • Serial follow-up with repeat CXR
    • If small and symptomatic (but hemodynamically stable) or large (> 3 cm between the lung and chest wall on chest x-ray) primary pneumothorax, iatrogenic, traumatic, or secondary pneumothorax
      • Immediate supplemental oxygen (4-6 L/min) via nasal cannula or mask with reservoir
      • Upright positioning
      • Symptomatic treatment
      • Tube thoracostomy
  • Open pneumothorax
    • Simple partially occlusive dressings taped at 3 out of 4 sides of the lesion
    • Followed by thoracostomy
    • Observe for development of tension pneumothorax
  • Tension pneumothorax
    • Emergency chest decompression via chest tube placement if immediately available
    • Otherwise perform emergency needle thoracostomy, followed by chest tube placement

Procedures

  • Chest tube placement
    • Approaches
    • Procedure
      • Local anesthesia
      • Incision of the skin and blunt dissection down to the upper margin of the rib within the respective ICS → cranial subcutaneous tunneling → opening of the parietal pleura approx. 1–2 ICS above the cutaneous incision
      • Insertion and placement of the chest tube depends on the injury
        • Air → apically, close to the pleural cupula
        • Fluid (e.g., blood, effusion) → caudally
      • Fixation of pleural drain to the chest wall
      • Application of suction with a negative pressure of -20 to -25 cmH2O for 3–5 days or until the air leak has stopped.
      • A water-seal may be used (a valve prevents entrance of air into the pleural space).
  • Needle thoracostomy
    • Immediate insertion of a large-bore needle into the 2nd intercostal space along the midclavicular line (followed by insertion of a chest tube)
    • The finger of a rubber glove can be used as a valve
  • Surgery
    • Indications
      • Repeated ipsilateral pneumothorax episodes
      • Unexpanded lung > 5 days despite chest tube placement
      • Air leak > 7 days
      • Bilateral or contralateral pneumothorax
      • Associated high risk occupation
      • Extensive underlying lung disease
      • Lymphangiomyomatosis
    • Procedures
      • Video-assisted thoracoscopic surgery (VATS)
      • Thoracotomy if necessary
    • Approaches
      • Stitching of the leak or resection of the lung regions that have bullae, if necessary (apical lung resection)
      • Pleurodesis
        • Chemical/pharmacological (administration into the pleural space): talc powder , bleomycin, tetracycline
        • Mechanical/surgical: pleural abrasion, partial (apical) parietal pleurectomy

Tension pneumothorax is a clinical diagnosis and medical emergency! Immediate emergency chest decompression is indicated! Do not intubate and ventilate without decompressing first!

Complications

  • Complete pulmonary collapse → respiratory failure
  • Tension pneumothoraxcardiac failure
  • Mediastinal flutter in case of open pneumothorax → hemodynamic shock
  • Hemothorax in cases of trauma
  • Pneumomediastinum
  • Pneumoperitoneum
  • Recurrence
  • Post-surgical/-procedural complications
    • Persistent fistula with continuous air leak
    • Injury to intercostal nerves and vessels
    • Infection

References:[1]

We list the most important complications. The selection is not exhaustive.

  • 1. Daley BJ, Mancini MC. Pneumothorax. In: Pneumothorax. New York, NY: WebMD. http://emedicine.medscape.com/article/424547-overview#a5. Updated July 20, 2016. Accessed December 7, 2016.
  • 2. Shankar PS . Subcutaneous Emphysema From Bronchocavitary Subcutaneous Fistula. Lung India. 2008; 25(2): pp. 73–74. doi: 10.4103/0970-2113.44123.
  • 3. Agabegi SS, Agabegi ED. Step-Up To Medicine. Baltimore, MD, USA: Lippincott Williams & Wilkins; 2013.
  • Herold G. Internal Medicine. Cologne, Germany: Herold G; 2014.
  • Choi WI. Pneumothorax. Tuberc Respir Dis (Seoul). 2014; 76(3): pp. 99–104. doi: 10.4046/trd.2014.76.3.99.
last updated 10/27/2018
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