Pressure change
There is a slight negative pressure in the pleural cavity at rest. This is the force that keeps the lung at the chest wall. If the pressure becomes positive, the elastic pull of the lung pulls it away from the chest wall, and the released space is filled with air (pneumothorax) or liquid. Pneumothorax is divided into spontaneous and traumatic. Spontaneous is the condition caused by the rupture of the pulmonary alveoli and the visceral pleura. It can be primary, that is, not associated with any pulmonary pathology, or secondary, when the gap becomes a consequence of the disease - for example, emphysema, chronic obstructive pulmonary disease or tuberculosis. The change in external pressure that causes chest expansion, for example during a high altitude flight, also predisposes to the development of pneumothorax. It happens that a tissue flap is formed at the site of the rupture, acting as a valve. During inspiration, the "valve" opens and air is sucked into the pleural cavity, when exhaled, it closes, blocking the air in the pleural area. Thus, with each inhalation, the volume of air in the pleural space increases. The lung and mediastinum (the anatomical space located in the middle of the thorax) are displaced in the opposite direction from the lesion, disrupting the normal lung. The venous return to the heart worsens and the cardiac output decreases. This condition is known as intense pneumothorax.
Symptoms
A patient with spontaneous pneumothorax feels a sudden onset of shortness of breath, accompanied by a stabbing pain in the chest. The mobility of the chest wall is limited on the affected side. Respiratory noise during auscultation (listening to the chest, usually with a stethoscope) is quieter than normal, and when you tap it, you can hear the sound of a drum-like shade. With intense pneumothorax, there is an increase in dyspnea and a displacement of the mediastinum, which can be detected by determining the position of the trachea over the jugular cutting of the sternum.
Research
The diagnosis is confirmed by radiography of the chest, which is done with a full exhalation. Small pneumothorax is sometimes not diagnosed, but it has no clinical significance. In a critical situation, there may be no time for examination, and the doctor should make a diagnosis based on the symptoms. In the case of intense pneumothorax, if there is no timely treatment, death may occur. To save a patient's life is a pleural puncture - the injection of a tube or needle into the pleural cavity to remove excess air. Physicians refer to intense pneumothorax to emergency conditions. In the absence of help, it threatens the life of the patient. The pressure in the pleural cavity should be reduced by inserting an intercostal cannula or a large hollow needle into the pleural cavity.
Diagnostics
If the patient's condition deteriorates rapidly, one should assume the presence of strenuous pneumothorax and take appropriate measures based on only clinical data, without the use of radiography. The needle inserted through the thoracic wall into the pleural cavity will lead to a decrease in pressure and will prevent the build-up of symptoms. Pneumothorax of small volume can be cured spontaneously. If only minimal symptoms are present, the lung recession does not exceed 20% of its volume, and the patient leads a sedentary lifestyle, it makes sense to limit the patient's observation with regular chest fluoroscopy to resorption of pneumothorax. In most cases, pneumothorax resolves within six weeks. If symptoms persist, pneumothorax should be resolved, either by aspirating air through a hollow needle, or by using pleural drainage. The intercostal cannula is inserted into the pleural cavity through the fourth or fifth intercostal space along the middle axillary line, and then fixed with a suture. The cannula is connected by a catheter to a vessel equipped with an outlet valve and filled with water. When the tube is below the water level, the system acts as a check valve and air is gradually expelled from the pleural cavity. Sometimes aspiration is required to remove excess air. Aspiration through the needle is performed by inserting a needle into the pleural cavity and sucking air using a three-way valve. This procedure is less traumatic for the patient and helps to reduce the time spent in the hospital. However, it is applicable only for small pneumothorax. If you quickly remove a large amount of air from the pleural cavity, the fluid in the chest can accumulate, which will lead to swelling of the expanded lung. It happens that pneumothorax is not allowed, since the initial opening in the visceral pleura remains open. This condition is known as bronchopleural fistula. In this case, you can close the defect with thoracotomy (surgical opening of the thoracic cavity) or thoracoscopy (a minimally invasive technique in which endoscopic instruments are used to visualize and restore the pleural cavity). 25% of pneumothoraxes subsequently recur and require final surgical correction. With large-volume pneumothorax, pleural drainage may also be ineffective. This happens if the patient already had bilateral pneumothorax in the past or he belongs to a professional group with a high risk of recurrence (for example, an airplane). In such cases, pleurodesis or pleurectomy may be performed. The purpose of pleurodesis is to fuse the visceral and parietal pleura with chemicals such as sterile talc or silver nitrate, or surgical scraping. The goal of pleurectomy is to remove all altered pleural sheets, but it leads to a significant scarring.