Open pneumothorax is an open communication of the pleural cavity with the external environment, in which atmospheric air freely circulates through a defect in the chest wall during breathing. The condition of a patient with an open pneumothorax is severe: there is excitement, rapid shallow breathing, cyanosis, air intake into the wound during inhalation and discharge during exhalation, subcutaneous emphysema. The diagnostic minimum includes examination, auscultation, percussion and chest radiography. The algorithm for eliminating an open pneumothorax involves the application of an occlusive dressing on the wound, drainage of the pleural cavity and surgical elimination of a defect in the chest wall.
An open pneumothorax is a pneumothorax characterized by communication of the pleural cavity with atmospheric air, both during inhalation and during exhalation; at the same time, intrapleural pressure becomes equal to atmospheric pressure. There is an outward-facing pneumothorax (when air circulates through a defect in the chest wall) and an inward-facing pneumothorax (when air enters through a defect in the bronchus or trachea). The most dangerous type is a bilateral open pneumothorax, which in almost 100% of cases very quickly ends in death. Patients with open pneumothorax are hospitalized in the departments of traumatology and thoracic surgery.
An open pneumothorax can transform into a closed one if the wound of the chest wall spontaneously closes and air ceases to flow into the pleural cavity. If the penetration of air through the wound canal continues only on inhalation, and on exhalation the wound is covered with a skin flap, not allowing air to leave the pleural cavity, a valvular pneumothorax develops.
Causes of open pneumothorax
In the vast majority of cases, an open pneumothorax is the result of penetrating wounds (knife, gunshot) of the chest. In this case, a continuous flow of air into the pleural cavity and outwards is carried out through the wound channel through a defect in the chest wall. Less often, the cause of pathology is destructive processes in the lung (lung abscess, cavernous tuberculosis, cavity form of lung cancer, etc.), leading to damage to the wall of the large bronchus. With this mechanism, the pleural cavity communicates with the external environment directly through the bronchial fistula.
The pathological physiology of an open pneumothorax is caused by a violation of pulmonary ventilation, direct exposure of atmospheric air to the pleura and hemodynamic disorders. A positive pressure in the pleural cavity on the side of the injury leads to the collapse of the lung and turning it off from breathing. At the same time, when inhaling, not only atmospheric air enters a healthy lung, but also air saturated with carbon dioxide from a collapsed lung. During exhalation, a small volume of air from the intact lung is “pumped” into the collapsed lung, partially straightening it. A., there is a mechanism of paradoxical breathing: the sleeping lung performs weak respiratory excursions, the reverse of the intact lung.
The depth of inspiration decreases, gross ventilation disorders, gas exchange disorders, acute respiratory and heart failure develop. Shunting of blood from a collapsed lung causes rapidly increasing hypoxemia and hypercapnia. Fluctuation of intrapleural pressure can cause mediastinal balloting during inhalation and exhalation, which is dangerous by displacement of the heart, aorta, inflection and compression of large vessels and bronchi. The streams of incoming and outgoing atmospheric air irritate the receptor apparatus of the pleura, cause its drying and cooling. Without timely help, victims with an open pneumothorax can quickly die from cardiopulmonary shock.
Symptoms and diagnosis
The general condition of a patient with an open pneumothorax is usually severe. There is excitement and anxiety. I am worried about acute stabbing pain in the chest, which increases with inhalation and coughing. Breathing becomes rapid, shallow; pulse is frequent, weak filling, blood pressure decreases. The skin becomes pale in color with a cyanotic tinge.
With the traumatic nature of an open pneumothorax, the victims usually take a position lying on the injured side of the chest. On examination, a gaping wound is visible in the chest area, into which air is sucked in with a noise at the entrance, and during exhalation, air and foamy blood come out with a whistle and squelch. Seeking relief, patients instinctively seek to cover the wound with a hand, clothes or other improvised means. In the case of air escaping under the skin, subcutaneous emphysema develops.
In the presence of a long narrow wound canal, a so-called “sucking pneumothorax” may occur – in this case, the wound opens only at the moment of deep breathing or coughing, and signs of cardiopulmonary insufficiency increase gradually and are not life-threatening for a long time. Traumatic open pneumothorax in most cases is combined with hemothorax (hemopneumothorax), so the severity of the patient’s condition is often aggravated by blood loss and hypovolemic shock.
The chest becomes asymmetrical due to the “shutdown” of the affected lung from the act of breathing. Percussion on the side of the injury is determined by tympanitis; auscultation – sharply weakened breathing. According to chest X-ray data, open pneumothorax reveals gas in the pleural cavity, lung collapse, flotation and mediastinal displacement. With the combination of a clinical and radiological picture with an indication of an open chest injury, the diagnosis becomes obvious. To verify the diagnosis, a pleural puncture may be required.
Treatment for open pneumothorax
The primary measure to be taken at the scene of the incident is the transfer of an open pneumothorax to a closed one. This is achieved by closing the wound defect with a sealed (occlusive) bandage. Such a bandage must meet a number of requirements: its dimensions must be larger than the wound, it must be airtight (for which an oilcloth material, plastic wrap, compress paper or a thick cotton-gauze bandage is usually used) and securely fixed to the skin surface with a bandage or adhesive plaster. At the same time, anesthesia, medical support of the cardiovascular and respiratory systems, replenishment of blood loss, restoration of airway patency, oxygen therapy or ventilation are carried out.
In a hospital, a patient with an open pneumothorax undergoes primary surgical treatment and suturing of the wound. In order to decompress the pleural cavity, its drainage is carried out by Bulau drainage. In case of lung damage, thoracotomy with revision of the pleural cavity, suturing of the lung wound or resection intervention is indicated.
In a situation where an open pneumothorax is caused not by trauma, but by destructive processes in the lung tissue, treatment is based on the underlying disease. In order to straighten the lung, constant aspiration of air and exudate is established. If the defect in the bronchus does not close on its own, resort to temporary obturation (filling) of the bronchus with a special foam plug. Against this background, conditions are created for the expansion of the lung, or the obliteration of the pleural cavity occurs with the elimination of the pneumothorax. In other cases, the issue of operational tactics is being resolved.
Open pneumothorax is always difficult, it can be complicated by pleuropulmonary shock, pneumonia, pleural empyema, lung gangrene. The prognosis of the disease is always extremely serious, and in case of untimely care or the bilateral nature of the pneumothorax, it is unfavorable.
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