Open pneumothorax is a pneumothorax with a chest wall defect allowing direct communication with the external environment; when the opening is sufficiently large, respiratory mechanics are impaired. Diagnosis is with physical examination. Treatment is with partially occlusive dressing followed by tube thoracostomy.
Trauma causing a pneumothorax may result in an unsealed opening in the chest wall; this is called an open pneumothorax. When patients with an open pneumothorax inhale, the negative intrathoracic pressure generated by inspiration causes air to flow into the lungs through the trachea and concurrently into the intrapleural space through the chest wall defect. There is little airflow through small chest wall defects and hence little effects on ventilation. However, when the opening in the chest wall is sufficiently large (when the defect is about two-thirds the diameter of the trachea or larger), resistance to airflow is less through the defect than through the trachea. This allows more air to pass through the chest wall defect than through the trachea into the lung. Larger defects can eliminate ventilation on the affected side. Inability to ventilate the lungs causes respiratory distress and respiratory failure.
Open Pneumothorax
This figure shows an open pneumothorax, which occurs when a chest wall defect allows air to pass directly between the pleural space and the external environment. Yumagema/stock.adobe.com |
Spontaneous pneumothorax is discussed elsewhere.
Symptoms and Signs of Open Pneumothorax
An open pneumothorax presents with a visible chest wall defect. The air entering the wound typically makes a characteristic sucking sound (sucking chest wound) with respiration. In awake patients, the chest wound is painful. Patients have dyspnea, tachypnea, and respiratory distress. They have decreased or absent breath sounds on the affected side. Some patients develop subcutaneous emphysema with crepitus on palpation of the chest wall, which is caused by air dissection into the subcutaneous tissues.
Diagnosis of Open Pneumothorax
Physical examination
In patients with thoracic trauma, open pneumothorax is diagnosed based on physical examination and requires inspecting the entire chest wall surface.
Treatment of Open Pneumothorax
Partially occlusive dressing followed by tube thoracostomy
Immediate management of open pneumothorax is to cover the wound with a rectangular sterile occlusive dressing that is closed securely with tape on only 3 sides. The dressing prevents atmospheric air from entering the chest wall during inspiration but allows any intrapleural air out during expiration. Tube thoracostomy should be performed when the patient is stabilized. The wound may require later surgical repair.
