What Causes A Tension Pneumothorax?
Tension pneumothorax is the progressive built-up of air within the pleural space. When the patient cannot compensate and if not treated immediately patient can even die of tension pneumothorax. Therefore it’s very important to identify patients with tension pneumothorax and treat them as quickly as possible.
What Causes A Tension Pneumothorax?
Tension pneumothorax is the progressive built-up of air within the pleural space. A tension pneumothorax develops when a ‘one-way valve‘ is created and air leak occurs either from the lung or through the chest wall to the pleural space. Causes are penetrating injury to the chest, closed pneumothorax progressing into a tension pneumothorax, spontaneous pneumothorax progressing into a tension pneumothorax, patients who are on positive pressure ventilation and iatrogenic lung injury also can cause tension pneumothorax. The most common cause for tension pneumothorax is penetrating lung injury. Tension pneumothorax is a life threatening condition as it leads to respiratory and circulatory instability, and if not treated immediately can cause death.
Penetrating Injury To The Chest
Most common cause of tension pneumothorax is penetrating injury (trauma) to the chest. It can be a stabbing injury or gunshot. Injury to pleural tissue can cause the lung to collapse and air can leak out to the pleural space. The tension can built up and it can cause tension pneumothorax.
This is another cause for tension pneumothorax there will be no open injury in the chest but the blunt trauma could have caused a pneumothorax and if not identified initially it can progress into a tension pneumothorax e.g. blunt trauma can fracture the rib, the fractured rib can cause a lung injury, and air will leak to the pleural space.
Even patients with spontaneous pneumothorax can progress to tension pneumothorax.
Iatrogenic Lung Injuries
Pneumothorax which occur due to a complication in a surgery, medical treatment or investigation
Sometimes during chest surgery the surgeon can cause accidental injuries e.g. due to subclavian central vein puncture. This can give rise to a tension pneumothorax and the surgeon as well as the staff should be vigilant about this.
Positive pressure ventilation
Tension pneumothorax may develop insidiously, especially in patients with positive pressure ventilation. This can occur immediately and sometimes after few hours therefore, monitoring the patient’s vital signs are important.
- Pleural tap or biopsy.
- Transbronchial biopsy.
How Does Tension Pneumothorax Occur?
When you breathe the air goes to the lung and then oxygen is exchanged within the lung blood vessels (perfusion) which carries oxygenated blood to the heart. Then when you breathe out the air goes out of the lung. The pleura are two membranes which cover the lung and the space in between the pleura is called pleural space. Pleural space is filled with a fluid. No air enters the pleural space normally.
As mentioned above tension pneumothorax is the progressive built-up of air within the pleural space. A tension pneumothorax develops when a ‘one-way valve ‘is created and air leak occurs either from the lung or through the chest wall.
Air is forced into the pleural space without any means of escape, completely collapsing the affected lung. There is less air that can be exchanged for perfusion in the lung. Once the lung is collapsed the pressure tends to compress the mediastinum to the opposite side to the unaffected lung. (The mediastinum is important regions of the body located between the lungs the structures that lie in this region include the heart, the esophagus, the trachea, and large blood vessels).
This will decrease the venous return to the heart and reduce the cardiac output. Compression of the unaffected lung (normal lung) will further reduce the oxygen perfusion. This leads to respiratory and circulatory instability, which is called tension pneumothorax and may even result in death if not treated immediately.
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- What is Pneumothorax in Infants, Know its Causes, Symptoms, Treatment
- How Long Does It Take To Recover From A Pneumothorax?
- How Do You Fix A Pneumothorax?
- What Causes Pneumothorax?
- What Causes Spontaneous Pneumothorax?
- What Is Closed Pneumothorax?