Pleural cavity is composed of pleural wall layer and visceral layer, which is a closed potential cavity without air. Pleura is damaged for any reason, and air enters the pleural cavity, which is called pneumothorax. At this time, the pressure in pleural cavity rises, even the negative pressure becomes positive pressure, which makes the lungs compressed, and the blood flow of venous return to the heart is blocked, resulting in different degrees of pulmonary and cardiac dysfunction.

Artificial pneumothorax, also known as artificial pneumothorax, artificially injects filtered air into pleural cavity to identify chest diseases under X-ray. Pneumothorax caused by chest trauma and acupuncture treatment is called traumatic pneumothorax. The most common pneumothorax is the rupture of lung tissue and visceral pleura caused by lung diseases, or the spontaneous rupture of bullae and tiny bubbles near the lung surface, and the air in the lungs and bronchi escapes into the pleural cavity, which is called spontaneous pneumothorax.

[Edit this paragraph] Etiology and pathogenesis

I. Reasons

1. Traumatic pneumothorax: Common chest injuries, including sharp instrument stab wounds and bullet penetrating injuries, dislocated rib fracture ends stabbing the lungs, and lung injuries in diagnostic medical operations, such as needle puncture lung biopsy and artificial pneumothorax.

2. Secondary pneumothorax: bronchopulmonary diseases penetrate into the chest to form pneumothorax. Such as obstructive pulmonary disease caused by chronic bronchitis, pneumoconiosis and bronchial asthma, pulmonary interstitial fibrosis, alveolar emphysema and bullae caused by partial airway occlusion of honeycomb lung and bronchial lung cancer, purulent pneumonia near pleura, pulmonary abscess and tuberculous cavity, pulmonary mycosis, congenital pulmonary cyst, etc.

3. Idiopathic pneumothorax: it means that there is no history of respiratory diseases, but there may be pulmonary bullae under the pleura. Once ruptured, it is called idiopathic pneumothorax, which is more common in slender young men.

4. Chronic pneumothorax: refers to pneumothorax that has not been completely expanded after 2 months. The reasons are: encapsulated liquid pneumothorax with difficulty in absorption, pneumothorax formed by pleural fistula, pulmonary bullae or congenital bronchial cyst difficult to heal, airway obstruction or atrophy, and the lung is covered with a thick institutionalized capsule to prevent lung recruitment.

Second, the mechanism

Pneumothorax is called spontaneous pneumothorax except trauma or artificial pneumothorax used for diagnosis and treatment. Spontaneous pneumothorax is mostly caused by the rupture of subpleural bubbles, but also by subpleural lesions or cavity rupture and pleural adhesion and tear. Pleural emphysema can be congenital or acquired; The former is congenital dysplasia of elastic fibers, which shows that the elasticity of alveolar wall decreases and bullae are formed after expansion, which is more common in slender men without obvious diseases in lung X-ray examination. The latter is more common in obstructive emphysema or inflammatory fibrous lesions. At this time, bronchioles negotiate semi-obstruction and distortion, resulting in valve mechanism to form emphysema. Swelling emphysema degenerates due to nutrient circulation disorder, so that it will rupture when coughing or pulmonary pressure increases.

Conventional X-ray examination shows that there are no obvious lesions in the lung, but there may be bullae under the pleura (mostly at the apex of the lung). Once ruptured, pneumothorax is called idiopathic pneumothorax, which is more common in young and tall men. Nonspecific inflammatory scar or congenital elastic fiber dysplasia may be the cause of subpleural pulmonary bullae.

Spontaneous pneumothorax is often secondary to basic lung lesions, such as tuberculosis (necrosis of focal tissue; Or rupture of pulmonary bullae formed by bronchiole semi-obstruction caused by scar during healing), chronic obstructive pulmonary disease (emphysema with high pressure and rupture in pulmonary bullae), lung cancer (bronchiole semi-obstruction, or cancer invading pleura, obstructive pneumonia, and then visceral pleura rupture), lung abscess, pneumoconiosis, etc. Sometimes there is ectopic endometrium on the pleura, which can rupture during menstruation and cause pneumothorax (menstrual pneumothorax).

Spontaneous pneumothorax is the most common secondary to chronic obstructive pulmonary disease and tuberculosis, followed by idiopathic pneumothorax. Spontaneous hemopneumothorax can be formed by rupture of visceral pleura or tear of pleural adhesion zone, in which blood vessels rupture. Pneumothorax will occur when people suddenly enter a low-pressure environment from a high-pressure environment without proper protective measures, and when the pressure of continuous positive artificial respiration is too high. Hard movements such as lifting heavy objects, coughing, sneezing, holding your breath or shouting and laughing are often the causes of pneumothorax.

[Edit this paragraph] Clinical types

According to the rupture of visceral pleura and its influence on the pressure in thoracic cavity, spontaneous pneumothorax can be divided into the following three types:

A, closed pneumothorax (simple)

When the expiratory lung retracts, or because of serosity exudation, the visceral pleural fissure closes itself, and no air leaks into the pleural cavity.

The measured pressure in the pleural cavity shows that the pressure rises, and the pressure drops and stops rising after pumping, indicating that the breach is no longer leaking. The residual gas in the pleural cavity will be absorbed by itself, so that the pressure in the pleural cavity will remain negative and the lungs will gradually expand.

Second, tension pneumothorax (high pressure)

Pleural breach forms valve obstruction, which opens when inhaling and air leaks into pleural cavity; When exhaling, it is closed, and the gas in the pleural cavity can no longer return to the respiratory tract through the breach. As a result, more and more gas accumulates in the pleural cavity, resulting in high pressure, which makes the lungs compressed, makes it difficult to breathe, pushes the mediastinum to the healthy side, hinders circulation, and requires emergency exhaust to relieve symptoms.

If the pressure in the affected pleural cavity rises, the positive pressure will be restored soon after pumping to negative pressure, and a continuous pleural cavity exhaust device should be installed.

Third, open pneumothorax (traffic)

Due to the adhesion and traction between the two layers of pleura, the breach continues to open, and air can freely enter and exit the pleural cavity during inhalation and exhalation. The pressure in the affected pleural cavity is about 0, and the pressure does not drop for several minutes after aspiration.

Pneumothorax can be divided into the following types according to the pathogenesis:

1. Post-traumatic pneumothorax: caused by stabbing the chest with a sharp instrument;

2. Primary pneumothorax: Pneumothorax of healthy people without obvious lung lesions is more common in young adults aged 20-40, especially men;

3. Secondary pneumothorax: pneumothorax secondary to various lung diseases, such as chronic bronchitis, emphysema, tuberculosis and lung cancer.

Primary pneumothorax is usually caused by congenital pulmonary tissue hypoplasia, pulmonary bullae or subpleural pulmonary bullae, and the lesion is often located at the tip of the lung. Secondary pneumothorax is caused by primary pulmonary lesions, the rupture of subpleural pulmonary bullae or the direct damage to pleura caused by the lesions themselves.

Spontaneous pneumothorax is mostly unilateral, with only about 65,438+00% on both sides, while the probability of secondary pneumothorax on both sides is very high. Patients often have sudden chest pain after pneumothorax, which is sharp and persistent stabbing pain or knife cutting pain. Inhalation is aggravated, mostly in the chest and armpit, and can radiate to the shoulders, back and upper abdomen, thus causing dyspnea. Its severity is closely related to the speed and type of pneumothorax, the degree of lung atrophy and the basic function of lung. Unilateral closed pneumothorax, especially young people with normal lung function, can have no obvious dyspnea, even 80-90% of the lungs are compressed or feel a little short of breath when moving and going upstairs, while tension pneumothorax or original obstructive emphysema. Irritating dry cough is caused by gas stimulating pleura, which is mostly not serious, has no sputum or occasionally has a small amount of bloodshot sputum, which may come from broken lung.

[Edit this paragraph] Clinical manifestations

Patients often have inducing factors such as holding heavy objects, holding their breath and strenuous exercise. But some patients also have pneumothorax during sleep. The patient suddenly feels chest pain, shortness of breath, holding his breath on one side, coughing, but less phlegm. A small amount of closed pneumothorax has shortness of breath at first, but it gradually stabilizes after several hours, and X-rays may not necessarily show lung compression. If the patient has a large volume or extensive lung diseases, the patient often cannot lie flat. If you lie on your side, you will be forced to lie on the affected side of pneumothorax to relieve shortness of breath. The degree of dyspnea in patients is related to the amount of pneumatosis and the scope of the original lung lesions. When pleural adhesion and lung function damage occur, even a small amount of localized pneumothorax can cause obvious chest pain and shortness of breath.

Tension pneumothorax is caused by sudden chest bulge, lung compression and mediastinal displacement, which leads to serious respiratory and circulatory disorders. Patients with nervous expression, chest tightness and even arrhythmia often struggle to sit up, fidget, cyanosis, cold sweat, rapid pulse, collapse, even respiratory failure, unconsciousness.

When pneumothorax is complicated on the basis of severe asthma or emphysema, symptoms such as shortness of breath and chest tightness are sometimes difficult to detect, so we should carefully compare them with the original symptoms and do chest X-ray examination. Physical examination showed that the trachea moved to the healthy side, the chest had pneumatosis, the affected chest bulged, the respiratory movement and tremor weakened, the percussion echo or drum sound was too much, and the auscultation breath sound weakened or disappeared. The right pneumothorax can reduce the voiced boundary of the liver. When there is a hydropneumothorax, you can smell the vibration in the chest cavity. Hemopneumothorax loses too much blood, blood pressure will drop, and even hemorrhagic shock will occur.

X-ray examination is an important method to diagnose pneumothorax, which can show the degree of lung atrophy, lung lesions, pleural adhesion, pleural effusion and mediastinal displacement. The appearance of light band near mediastinum suggests mediastinal emphysema. The transparency of pneumothorax is increased outside the line, and no lung line can be seen. Sometimes the pneumothorax line is not obvious enough, so the patient can be asked to exhale, and the lung volume is reduced and the density is increased, which is in contrast with pneumothorax, which is beneficial to find pneumothorax. When a large number of pneumothorax occurs, the lung retracts to the hilum, and the outer edge is curved or lobulated, which should be distinguished from central lung cancer.

Tuberculosis or lung inflammation leads to multiple pleural adhesions. When pneumothorax occurs, it is mostly a localized cyst, and sometimes the air cavities are interconnected. If the pneumothorax extends to the lower thoracic cavity, the costal diaphragm angle appears sharp. If complicated with pleural effusion, look at the liquid level (hydropneumothorax). The posterior and anterior X-ray examination of localized pneumothorax sometimes misses the diagnosis, and pneumothorax can only be found by slowly rotating the body under fluoroscopy.

[Edit this paragraph] Diagnosis and differential diagnosis

Sudden chest pain on one side, accompanied by dyspnea and pneumothorax, can be initially diagnosed. X-ray showing signs of pneumothorax is the basis of diagnosis. When X-ray examination is not allowed unconditionally or in critical condition, you can try it on at the place where the signs of pneumothorax on the affected side are the most clear, and take air for pressure measurement. If it is positive pressure and gas is pumped out, it means that there is pneumothorax, that is, gas should be pumped out to relieve symptoms, and the change of pressure in the chest cavity after air is pumped out should be observed to judge the type of pneumothorax.

Spontaneous pneumothorax is sometimes similar to other cardiopulmonary diseases and should be differentiated.

First, bronchial asthma and obstructive emphysema

There is shortness of breath and dyspnea, and the signs are similar to those of spontaneous pneumothorax, but the dyspnea of long-term emphysema is gradually aggravated. Patients with bronchial asthma have a history of asthma recurrence for many years. When patients with asthma and emphysema have dyspnea and sudden aggravation of chest pain, the possibility of pneumothorax should be considered, and X-ray examination can distinguish it.

Second, acute myocardial infarction

Patients also have sudden chest pain, chest tightness, even dyspnea, shock and other clinical manifestations, but often have a history of hypertension, atherosclerosis and coronary heart disease. Signs, electrocardiogram and chest X-ray are helpful for diagnosis.

Third, pulmonary embolism.

There are clinical manifestations similar to spontaneous pneumothorax, such as chest pain, dyspnea, cyanosis, etc., but patients often have hemoptysis and low fever, and often have a history of thrombophlebitis of lower limbs or pelvic cavity, fractures, serious heart disease, atrial fibrillation, etc., or occur in elderly patients who have been in bed for a long time. Physical examination and X-ray examination are helpful for identification.

Fourth, pulmonary bullae

Under X-ray, the bullae around the lungs are sometimes mistaken for pneumothorax. Pulmonary bullae can be formed by congenital development, or tension cyst or huge cavity can be formed by valve blockage in bronchus. The onset is slow and shortness of breath is not serious. Chest fluoroscopy shows that pulmonary bullae or bronchogenic cysts are round or oval light-transmitting areas, and the edges of pulmonary bullae are wireless pneumothorax lines, and there are tiny stripes in pulmonary bullae, which are pulmonary lobules or vascular residues. Pulmonary bullae expand to the periphery, compressing the lung apex, costal diaphragm angle and cardiac diaphragm angle, while pneumothorax is a light band outside the chest, in which no transverse stripes of lung can be seen. The pressure in pulmonary bullae is similar to atmospheric pressure, and the volume of pulmonary bullae has no obvious change after aspiration.

Others such as peptic ulcer perforation, diaphragmatic hernia, pleurisy and lung cancer, sometimes due to sudden chest pain, epigastric pain and shortness of breath, should also be differentiated from spontaneous pneumothorax.

[Edit this paragraph] Treatment

The principle of treatment is to exhaust properly according to different types of pneumothorax, remove the obstacles of pneumothorax to breathing and circulation, make the lungs recover as soon as possible, and deal with complications and primary diseases at the same time.

First of all, exhaust therapy

According to the symptoms, signs and X-ray findings, we can judge what kind of pneumothorax it is, whether it needs immediate exhaust treatment, and if so, what method is appropriate.

(1) Closed pneumothorax When the volume of pneumothorax is less than 20% of the volume of the side chest cavity, the gas can be absorbed by itself within 2-3 weeks, and there is no need to pump air, but the change of pneumothorax volume should be observed dynamically. When the air volume is large, it can be pumped once a day or every other day, and the pumping time should not exceed 1L until most of the lungs expand, and the remaining pneumothorax can be absorbed by itself.

(2) Hypertensive pneumothorax is serious and life-threatening, so it must be exhausted as soon as possible. Pneumothorax box can be used to measure pressure and exhaust simultaneously. In case of emergency, the sterile needle is inserted into the pleural cavity from the affected intercostal space, so that the high positive pressure pneumothorax can be discharged automatically and the symptoms can be alleviated. In case of emergency, a large syringe can be connected with three switches to pump air, or a pin can be inserted through the chest wall, and the end of the needle is connected with a water seal bottle for drainage, so that the high-pressure gas can be discharged in one direction. You can also use a thick injection needle to tie a rubber finger cuff at its tail, cut a small slit at the end of the finger cuff, and insert it into the pneumothorax for temporary and simple exhaust, so that high-pressure gas can be exhausted through the small slit. When the intrathoracic pressure drops to negative pressure, the cuff will collapse, the small cracks will be closed, and the outside air cannot enter the pleural cavity.

In order to exhaust air effectively and continuously, a sealed water-sealed bottle for thoracic drainage is usually installed. The intubation site is usually taken from the second intercostal space outside the clavicle midline or the fourth to fifth intercostal space in the axillary front line. If it is a localized pneumothorax, or if it is necessary to drain pleural effusion, it is necessary to select a suitable part for intubation and exhaust drainage under X-ray fluoroscopy. Before installation, measure the pressure at the selected position with a pneumothorax box to know the type of pneumothorax, then make a skin incision of 1.5-2cm in parallel along the upper edge of the rib under local anesthesia, puncture the pleural cavity with a trocar, take out the needle core, and insert the sterile hose into the thoracic cavity through the cannula. Generally, a large catheter or silicone tube is selected, and a duckbill-shaped opening is cut at its front end, and one or two side holes are cut to facilitate drainage. Alternatively, after skin incision, the intercostal tissue can be blunted to the pleura, and then the catheter can be directly sent into the pleural cavity by penetrating the pleura. After the catheter is fixed, the other end of the catheter is placed at 1-2 cm below the water surface of the water-sealed bottle to keep the pressure in the pleural cavity below 1-2cmH2O. If the gas accumulated in the pleural cavity exceeds this positive pressure, the gas will escape from the water surface through the catheter.

1-2 days later, the patient did not feel short of breath. When the lungs are completely dilated by fluoroscopy or radiography, the catheter can be removed. Sometimes, although bubbles appear on the water surface, the patient's shortness of breath cannot be alleviated. It may be because the catheter is not smooth enough or partially slips out of the pleural cavity. If the catheter is blocked, it should be replaced.

If this kind of water-sealed bottle drainage still can't heal the pleural breach and the lung can't dilate for a long time according to fluoroscopy, we can choose to intubate at another part of the chest wall, or add a negative pressure suction closed drainage device at the original unobstructed drainage tube end. Because the vacuum cleaner may generate excessive negative pressure, the negative pressure should not exceed -0.8 to-1.2 kPa (-8 to-12 H2O) when using the pressure regulating bottle. If the negative pressure exceeds this limit, indoor air will enter the pressure regulating bottle through the pressure regulating pipe, so the negative suction pressure borne by the patient's chest will not be higher than -0.8 to-1.2 kPa (-8 to).

When closed negative pressure suction is used, the suction machine should be started continuously, but the lung is still not dilated after more than 12 hours, and the reason should be found. If there are no bubbles and the lungs are completely dilated, the drainage tube can be clamped to stop negative pressure suction and observed for 2-3 days. If the pneumothorax has not recurred, the drainage tube can be pulled out and the surgical incision can be covered with vaseline gauze immediately to prevent outside air from entering.

If the bottle is not sealed, it should be placed under the patient's chest (such as under the patient's bed) to prevent the water in the bottle from flowing back to the chest. All kinds of intubation should be strictly disinfected in the process of drainage and exhaust to avoid infection.

(3) Patients with a small amount of pneumothorax and no obvious dyspnea, after resting in bed and restricting their activities, or installing a water-sealed bottle for drainage, sometimes the pleural breach can be closed by itself and turned into a closed pneumothorax. If dyspnea is obvious, or patients with chronic obstructive pulmonary disease have pulmonary insufficiency, negative pressure suction can be tried. In the process of lung recruitment, the fissure will also close. If the rupture is large, or it continues to open due to pleural adhesion, and the patient's symptoms are obvious, and the simple exhaust measures do not work, the rupture can be observed by thoracoscope and closed by adhesion cautery. If there is no taboo, you can also consider opening the chest to repair the breach. Wiping parietal pleura with gauze during operation can promote postoperative pleural adhesion. If there are obvious lung lesions, lobectomy or segmental resection of the affected lung can be considered.

Second, other treatments.

Lung atrophy in patients with spontaneous pneumothorax affects gas exchange, forming right-to-left shunt, reducing oxygen saturation and increasing alveolar-arterial oxygen partial pressure. However, due to the decrease of blood flow in atrophic lung, the right-to-left shunt was corrected and the oxygen saturation recovered rapidly. Due to the existence of pneumothorax, restrictive ventilation dysfunction occurs, and lung volume such as vital capacity decreases, and respiratory failure may occur in severe cases. According to the patient's condition, give oxygen appropriately to treat the primary disease. Prevention and treatment of chest infection, antitussive and expectorant treatment, analgesia, rest and supportive treatment should also be paid attention to.

For menstrual pneumothorax, in addition to exhaust treatment, drugs that inhibit ovarian function (such as progesterone) can be added to prevent ovulation.

Three. Complications and their management

(1) Recurrent pneumothorax About 1/3 pneumothorax can recur ipsilateral within 2-3 years. For recurrent pneumothorax. Pleural repair should be done for patients who can tolerate surgery; For those who can not tolerate thoracotomy, pleural adhesion treatment can be considered. Available binders include tetracycline powder for injection, sterilized refined talcum powder, 50% glucose, vitamin C, tracheitis vaccine, streptokinase, OK432 (Streptococcus preparation) and so on. Its mechanism of action is to produce aseptic allergic pleurisy through biological and physical and chemical stimulation, which makes the two pleura adhere and the pleural cavity atresia, thus achieving the purpose of preventing and treating pneumothorax. Before injecting adhesive into the chest cavity, there should be negative pressure suction and closed drainage, and the lungs must be completely expanded. In order to avoid severe chest pain caused by drugs, lidocaine should be injected first, so that the patient can rotate his position to fully anesthetize the pleura, and the adhesive should be injected after 15-20 minutes. For example, 0.5- 1g tetracycline powder is dissolved in 100ml physiological saline, and then injected into the chest cavity through a drainage tube, so as to instruct the patient to repeatedly rotate the body position, so that the medicine is evenly coated on the pleura (especially the lung tip), and the tube is clamped for observation for 24 hours (if there are symptoms of pneumothorax, the tube can be opened at any time to exhaust), and the excess medicine in the chest cavity is sucked out. If you fail once, you can inject drugs repeatedly and observe for 2-3 days.

(2) Purulent pneumothorax: necrotizing pneumonia, lung abscess and caseous pneumonia caused by Staphylococcus aureus, pneumonia, Pseudomonas aeruginosa, tuberculosis and various anaerobic bacteria may be complicated with purulent pneumothorax. The condition is critical, often forming bronchopleural fistula. Pathogens can be found in pus, and besides proper application of antibiotics (local and systemic), surgical treatment should also be considered according to specific conditions.

(3) Hemopneumothorax Spontaneous pneumothorax with intrapleural hemorrhage is caused by rupture of blood vessels in pleural adhesion area. After the lungs are completely dilated, the bleeding can stop by itself. If bleeding continues, besides aspiration and proper blood transfusion, we should also consider thoracotomy and ligation of bleeding blood vessels.

(4) mediastinal emphysema and subcutaneous emphysema After high-pressure pneumothorax is aspirated or closed drainage is installed, subcutaneous emphysema of chest wall can appear along pinhole or incision. The escaping gas also spreads to the subcutaneous layer of the abdominal wall and upper limbs. High-pressure gas enters the interstitial lung, along the vascular sheath, and enters the mediastinum through the hilum. Mediastinal gas can also enter the subcutaneous tissue of neck and chest and abdomen along fascia. On the X-ray film, the subcutaneous and mediastinal zona pellucida can be seen, and the great vessels in mediastinum are compressed. The patient felt pain behind the sternum, shortness of breath and cyanosis, decreased blood pressure, narrowed or disappeared the boundary of voiced heart sounds, and the heart sounds were far away, and a rough crack synchronized with the heartbeat could be heard in the mediastinum.

Subcutaneous emphysema and mediastinal emphysema can be absorbed by themselves with the discharge and decompression of gas in pleural cavity. Inhalation of higher concentration of oxygen can increase the oxygen concentration in mediastinum, which is beneficial to the dissipation of emphysema. If the tension of mediastinal emphysema is too high, which affects breathing and circulation, puncture of suprasternal fossa or incision and exhaust can be done.

[Edit this paragraph] Traumatic pneumothorax

Pneumothorax is called pneumothorax. The incidence of traumatic pneumothorax is about 15% ~ 50% in blunt trauma and 30% ~ 87.6% in penetrating trauma. In most cases, the air of pneumothorax comes from the puncture of the broken end of rib to the lung (superficial lung rupture, deep bronchiolar laceration), or the contusion of bronchus or lung tissue caused by violence, or the rupture of bronchus or lung caused by the sharp increase of pressure in airway. Sharp instrument injury or firearm injury penetrates the chest wall, injuring the lungs, bronchi, trachea or esophagus, and can also cause pneumothorax, mostly hemopneumothorax or empyema. Occasionally, closed or penetrating diaphragmatic rupture is accompanied by gastric rupture, leading to empyema.