A tension pneumothorax occurs when air is drawn into the pleural space from a lacerated lung or through a small hole in the chest wall. In either case, the air that enters the chest cavity with each inspiration is trapped there; it cannot be expelled through the air passage or the small hole in the chest wall.
Thus, tension or pressure is built up within the pleural space, which causes the lung to collapse and the heart, the great vessels, and trachea shift toward the unaffected side of the chest. Both respiration and circulatory function are impaired because with increased intrathoracic pressure, venous return to the heart is compromised, causing decreased cardiac output and impairment of peripheral circulation. In extreme cases, the pulse may be undetectable, known as pulseless electrical activity (PEA). The clinical picture is one of air hunger, agitation, hypotension, tachycardia, profuse diaphoresis, and cyanosis.
Relief of tension pneumothorax is considered an emergency measure.
If a tension pneumothorax is suspected, they should immediately be given a high concentration of oxygen to treat the hypoxia. In an emergency situation, a tension pneumothorax can be converted quickly to a simple pneumothorax by inserting a large-bore needle at the second intercostal space mid-clavicular line on the affected side. This will relieve the pressure and vent the intrathoracic air to the outside. A chest tube is then inserted and connected to suction to remove the remaining air and fluid and re-expand the lung.
If the lung expands and leakage from the lung stops, further drainage may be unnecessary. If the lung continues to leak, as evidenced by the re-accumulation of an inexhaustible volume of air during the thoracentesis, the air must be removed by a chest tube with water-seal drainage.
Tension pneumothorax is classified as either traumatic or spontaneous. Traumatic pneumothorax may be further classified as open or closed. Note that an open wound may cause closed pneumothorax if communication between the atmosphere and the pleural space seals itself off. Spontaneous pneumothorax. Which is also considered closed, can further classified as primary or secondary.
Spontaneous pneumothorax can result from:
-Ruptured congenital blebs
-Ruptured emphysematous bulllae
-Tubercular or malignant lesions that erode into the pleural space
-Interstitial lung disease, such as eosinophilic granuloma
-Traumatic pneumothorax can result from:
-Insertion of a central venous catheter
-Thoracic surgery
-Thoracentesis or closed pleural biopsy
-Penetrating chest injury
-Transbronchial biopsy
Treatment is conservative for spontaneous pneumothorax in cases where no sign of increased pleural pressure appear, lung collapse is less than 30% and the patient shows no sign of dyspnea or other indications of physiologic compromise. Such treatment consists of bed rest or activity as tolerated, careful monitoring of blood pressure, pulse rate or respiration and oxygen administration
When more than 30% of the lung has collapsed. Reexpansion of the lung is performed by placing a thoracotomy tube in the second or third intercoostal space at the midclavicular line. This procedure is done t o allow air to rise to the top of the intrapleural space. The tube is connected to an underwater seal with suction at low pressures.
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