A simple Pneumothorax is where a lung or a portion of a lung has collapsed due to air escaping into the pleural space between the lung and chest wall. Depending on the severity or cause, this type of condition may heal on its own or need treatment.
A Tension Pneumothorax is a condition in which air continues to accumulate in the pleural space. This usually develops when there is a lung or chest wall injury. The patient continues to breathe air into the injured lungs, but the air leaks into the chest cavity. As the air starts to accumulate, it creates pressure and build up inside the thorax, compressing the lung and pushing the mediastinum (center portion of the chest) to the opposite side of the chest, thus increasing intrathoracic pressure and decreasing venous return to the heart. This can lead to circulatory instability with decreased cardiac output and shock. This condition requires immediate treatment.
Causes of Tension Pneumothorax
Not every pneumothorax is caused by a chest injury. A pneumothorax can also occur spontaneously. Primary spontaneous Pneumothorax (PSP), occurs in the absence of injury or known lung disease. It typically occurs in tall, thin, male subjects. Risk factors include male gender, smoking, family history of pneumothorax, lung disease, mechanical ventilation and history of a previous pneumothorax. Almost all patients with PSP report sudden chest pain on the side where the pneumothorax occurs, and dyspnea that is usually mild. Secondary spontaneous pneumothorax occurs due to underlying lung disease, most commonly seen in patients with chronic obstructive pulmonary disease (COPD).
Tension pneumothorax is primarily caused by blunt or penetrating trauma, stabbing or gunshot wounds being the most common cause. This type of trauma can lead to lung collapse and death, unless reversed by effective treatment.
Signs and Symptoms
A primary or secondary spontaneous pneumothorax may include acute onset of chest pain and shortness of breath. This is most common with secondary spontaneous pneumothorax.
Tension pneumothorax is typically characterized by hypotension, hypoxia and tachycardia. Upon examination, there are no breath sounds on the affected side and the trachea moves away from the affected side. The thorax may also be hyperresonant with distended jugular veins. If the patient is on mechanical ventilation, the airway pressure alarms will be triggered.
Tension Pneumothorax Diagnosis
A pneumothorax is generally diagnosed using a chest X-ray or CT scan. Tension pneumothorax can be differentiated clinically by its absence of breath sounds on the affected side and hyperresonance to percussion. As diagnosed by clinical findings, treatment should not be delayed for a tension pneumothorax.
Tension Pneumothorax Treatment
Treatment for a simple pneumothorax may include observation without oxygen, supplemental oxygen administration, simple aspiration, chest tube placement, one-way valve insertion, and thoracostomy with continuous suction.
Tension pneumothorax is an emergency and is treated by releasing the accumulated air from the pleural space. This is done by needle decompression followed by tube thoracostomy. Immediate needle decompression is performed by inserting a 14 -16G needle into the 2nd intercostal space in the midclavicular line. The needle is advanced until the air can be aspirated, taking the pressure off the lung and allowing the trapped air to rush out. After emergency treatment, tube thoracostomy should be done.