Atelectasis of the lung

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Atelectasis (collapse) of the lung is a loss of airiness in an area of the lung, occurring acutely or over a long period of time. In the affected collapsed area, a complex combination of airlessness, infectious processes, bronchiectasis, destruction and fibrosis is observed.

Etiology and pathogenesis • Obstruction of the bronchial lumen by plugs of viscous bronchial secretion, tumor, mediastinal cysts, endobronchial granuloma or foreign body • Increased surface tension in the alveoli due to cardiogenic or non-cardiogenic pulmonary edema, surfactant deficiency, infection • Pathology of the bronchial walls: edema, tumor, bronchomalacia, deformation • Compression of the respiratory tract and/or the lung itself, caused by external factors (myocardial hypertrophy, vascular abnormalities, aneurysm, tumor, lymphadenopathy) • Increased pressure in the pleural cavity (pneumothorax, effusion, empyema, hemothorax, chylothorax) • Restriction of chest mobility ( scoliosis, neuromuscular diseases, phrenic nerve palsy, anesthesia) • Acute massive pulmonary collapse as a postoperative complication (unrecognized and unsanitized obstruction of the main bronchus).

Genetic aspects are determined by the underlying disease (cystic fibrosis, bronchial asthma, congenital heart disease, etc.). Risk factors. Surgeries on the chest organs, COPD, tuberculosis, smokers, obese people and people with short and wide chests.

Pathomorphology • Capillary and tissue hypoxia causes fluid transudation. The alveoli are filled with bronchial secretions and cells, which prevents complete collapse of the atelectasis area. • The addition of infection causes fibrosis and bronchiectasis.

The clinical picture varies depending on the rate of development of bronchial occlusion, the extent of atelectasis and the presence of infection.

• Diffuse microatelectasis, small atelectasis, slowly developing atelectasis and middle lobe syndrome (chronic atelectasis of the middle lobe of the right lung due to compression by lymph nodes) may be asymptomatic.

• Extensive atelectasis due to acute occlusion is characterized by the following symptoms •• Pain on the affected side, sudden shortness of breath and cyanosis •• Cough •• Hypoxia with a significant decrease in paO2 with a tendency to its recovery during the first 24–48 hours due to weakening of blood flow in the atelectasis area • • Percussion: dullness of percussion sound over the area of atelectasis •• Auscultation ••• absence of breath sounds - with occlusion of the airways ••• bronchial breathing, if the airways are patent ••• moist rales with focal obstruction •• Decreased chest excursion •• Displacement apical impulse.

• Chronic atelectasis •• Shortness of breath •• Cough •• Percussion: dullness of percussion sound •• Auscultation: moist rales •• If infected: increased amount of sputum, rise in body temperature •• Recurrent bleeding from the affected area is possible.

Age characteristics • Early childhood: aspiration mechanism, pneumonia • Children: among the most common causes are mediastinal cysts, vascular anomalies • Elderly: among the most common causes are lung tumors, cicatricial stenosis, bronchiectasis.

Special studies • Chest X-ray in two projections •• triangular-shaped intense homogeneous shadow with clear boundaries, with the apex directed to the root of the lung, with a decrease in the volume of the affected area of the lung •• With atelectasis of the lobe or lung - persistent displacement of the mediastinum to the affected side, dome the diaphragm on the affected side is raised, the intercostal spaces are narrowed •• diffuse microatelectasis - an earlier manifestation of oxygen intoxication and acute respiratory distress syndrome: a “ground glass” picture •• rounded atelectasis - rounded shading with a base on the pleura, directed towards the root of the lung (“comet-shaped” tail of blood vessels and airways). More often occurs in patients exposed to asbestos and resembles a tumor •• right-sided midlobe and lingular atelectasis merge with the borders of the heart on the same side (Arman-Delisle sign) • Bronchoscopy is indicated to assess the patency of the airways • EchoCG to assess the condition of the heart in cardiomegaly • CT or MRI of the chest.

Treatment

• The regimen depends on the patient's condition. Physical activity should be encouraged.

• Acute atelectasis (including acute postoperative massive collapse) •• The main cause of atelectasis should be eliminated, sanitation bronchoscopy should be performed, especially in cases of obstruction of the bronchial lumen with viscous sputum or vomit •• In case of foreign body aspiration - endoscopic removal.•• Adequate oxygenation, respiratory hydration mixtures •• In severe cases, mechanical ventilation with positive expiratory pressure or the creation of continuous positive pressure in the respiratory tract in persons with neuromuscular weakness •• Postural drainage (the head of the bed is lowered so that the trachea is below the affected area), breathing exercises, early postoperative mobilization of the patient •• Physiotherapeutic procedures, massage •• Broad-spectrum antibiotics are prescribed from the first day.

• Chronic atelectasis •• Postural drainage, breathing exercises (spirosimulator) •• Ventilation of the lungs with positive expiratory pressure or creation of constant positive pressure in the airways in persons with neuromuscular weakness •• Broad-spectrum antibiotics for purulent sputum •• Surgical resection of an atelectatic segment or lobe with recurrent infection and/or bleeding from the affected area •• If the obstruction is caused by a tumor, then the choice of treatment method is determined by the nature and extent of the tumor, and the general condition of the patient.

• Bronchodilators (salbutamol, fenoterol) - auxiliary value.

Complication : lung abscess (rare).

Prevention • Smoking cessation • Prevention of aspiration of foreign bodies and liquids, incl. vomit • In the postoperative period, the use of long-acting painkillers should be limited • Early postoperative mobilization of the patient • Breathing exercises.

ICD-10 • J98.1 Pulmonary collapse

What is atelectasis?

Atelectasis is the collapse or collapse of the lung, resulting in decreased or absent gas exchange. It is usually a unilateral disease affecting part or all of one lung. Atelectasis is a condition in which the alveoli are deflated to little or no volume, as opposed to pulmonary consolidation, in which they are filled with fluid. It is often called pulmonary collapse , although the term can also refer to pneumothorax.

The condition is very often detected on chest x-rays and other radiological studies and can be caused by a variety of common conditions and diseases. Although atelectasis is often described as collapse of lung tissue, it is not synonymous with pneumothorax, which is a more specific condition characterized by atelectasis. Acute atelectasis can occur as a postoperative complication or as a result of surfactant deficiency. In premature babies this leads to respiratory distress syndrome.

The term uses a combination of the forms atel— + ectasis from the Greek: ἀτελής, “incomplete” + ἔκτασις, “stretching.”

Prevention

Smokers can reduce the risk of developing atelectasis postoperatively by quitting smoking, if possible, 6 to 8 weeks before surgery. After surgery, patients are encouraged to breathe deeply, cough regularly, and begin moving as early as possible. The use of devices that stimulate voluntary deep breathing (stimulus spirometry) and certain exercises, including changes in body position to enhance the removal of mucus and other secretions from the lungs, may help prevent atelectasis.

Prevention of atelectasis is also achieved by deep breathing. If possible, conditions that cause shallow breathing over a long period of time should be treated.

Procedures and operations

Pleural puncture with manometry allows us to clarify the type of spontaneous pneumothorax. Intrapleural pressure indicators with closed spontaneous pneumothorax are positive or slightly negative. In the open form of pneumothorax they tend to zero, in the valvular form they tend to increase and are positive.

The aspirated fluid obtained as a result of puncture from the pleural cavity is sent to the laboratory to study the cellular composition and analyze the microflora . Thoracoscopy is performed to determine the size and location of the pleural fistula.

First aid for pneumothorax

When pneumothorax occurs (closed, open or valvular), emergency care is required. If possible, assistance should be qualified and provided in a specialized hospital. In some cases, competent and timely provision of first aid can save a human life. In case of open pneumothorax or suspected lung collapse, a certain sequence must be followed.

Emergency care algorithm for spontaneous pneumothorax:

Place the victim on an elevated surface to ensure the most favorable position for the respiratory system.
Apply an occlusive dressing to the wound surface, which during emergency care can be any means that ensures the tightness of the affected part in the chest cavity. Available means include plastic film, adhesive tape, and rubberized fabric. The occlusive dressing is fixed with bandages or any fabric pre-treated with a disinfectant or iodine. Proper application of a bandage helps prevent the entry of an infectious agent onto the wound surface and prevent the development of a bacterial infection. The area around the wound must be treated with baby cream or Vaseline. In a hospital setting, the doctor will treat the peri-wound surface with a special ointment and apply a special hydroactive napkin.
The patient must be anesthetized; the use of narcotic analgesics is allowed for severe pain.
To remove air and drain the pleural cavity with drainage, the patient undergoes a pleural puncture in a hospital setting.
Hormonal medications ( Dexamethasone ) are used to maintain normal blood pressure levels.
If necessary, resuscitation measures are carried out.

Causes and risk factors

The most common cause is postoperative atelectasis, characterized by splinting, that is, restriction of breathing after abdominal surgery.

Another common cause is pulmonary tuberculosis. Smokers and older people are also at increased risk. Outside of this context, atelectasis implies some obstruction of a bronchiole or bronchus, which may be internal to the airway (foreign body, mucus plug), from a wall (tumor, usually squamous cell carcinoma), or compressed externally (tumor, lymph node, tubercle). Another reason is poor surfactant distribution during inspiration, causing surface tension that tends to collapse the smaller alveoli. Atelectasis can also occur during sanitation of the respiratory tract, since air is removed from the lungs along with sputum. There are several types of atelectasis depending on the underlying mechanisms or extent of alveolar collapse; resorption (obstructive), compression, microatelectasis and contraction atelectasis. Relaxing atelectasis (also known as passive atelectasis) is when pleural effusion or pneumothorax disrupts the contact between the parietal and visceral pleura.

Risk factors associated with an increased likelihood of developing the disorder include:

type of surgery (thoracic, cardiopulmonary surgery);
use of muscle relaxants;
obesity;
high oxygen levels.

Factors not associated with the development of atelectasis include:

age;
the presence of chronic obstructive pulmonary disease (COPD) or asthma;
type of anesthetic.

Treatment of pneumothorax of the lungs

The main step in open pneumothorax is the application of a special occlusive dressing that will tightly and completely cover the wound. Additionally, measures are taken to maintain the normal functioning of the respiratory and cardiovascular systems.

Blood loss is replaced and pain relief is provided if necessary. In stationary conditions, surgical treatment and subsequent suturing of the wound defect in the chest are carried out with the formation through drainage of constant aspiration of air and outflow of exudate from the pleural cavity.

The extent of surgical intervention is determined by the nature of the damage with the maximum possible preservation of healthy lung tissue. After surgery is completed, a permanent drain is installed.

In the open form of pneumothorax, therapy is aimed at eliminating the underlying cause followed by drainage. If the damage is too extensive and there is no way to straighten the lung, temporary obstruction of the bronchial tube is performed using a special plug made of foam rubber or a similar material. Thanks to the plug, the flow of air into the pleural cavity is stopped and all the necessary conditions are created for the complete expansion of the previously collapsed lung. During bronchial obstruction, the visceral pleura fuses with the parietal pleura, which makes it possible to completely eliminate pneumothorax.

How long does it take for a lung to expand?

In case of spontaneous primary pneumothorax, oxygen inhalation is performed to accelerate the resorption of gases in the pleural cavity, which speeds up the process by 4 times. With standard breathing of normal air, air is absorbed at a very low rate - only 2% per day.

In 70% of patients with primary spontaneous pneumothorax of moderate volume, simple aspiration of air from the pleural cavity is considered effective. If more than 2.5 liters of gases are aspirated in a patient over 50 years of age, then doctors will most likely fail.

If everything went well, then 6 hours after aspiration there is no gas in the pleural cavity and the patient can be sent home the next day if his condition is stable. If after aspiration through the catheter the lung does not expand, then the catheter is connected to the Helmich valve or underwater draft, which are used as a drainage tube.

Pathogenesis

Primary spontaneous pneumothorax occurs as a result of rupture of subpleurally located emphysematous bullae, which are formed against the background of congenital defects of elastic pulmonary structures or against the background of cysts that have developed abnormally in their terminal bronchioles.

Until now, the pathogenesis of bullae formation remains unknown. It is believed that they are formed as a result of the degradation of elastic fibers in the lungs, which is caused by the activation of macrophages and neutrophils due to smoking. There is a shift in the balance between antiproteases, proteases and the antioxidant oxidation system. Formed bullae provoke inflammatory blockage of the small airways, which leads to an increase in intra-alveolar pressure and air enters the pulmonary interstitium.

The air moves towards the root of the lung, causing emphysema . Due to increased pressure in the mediastinum, the parietal mediastinal pleura ruptures with the development of pneumothorax. Increased intrapleural pressure prevents fluid from leaking into the pleural cavity.

As a result of a large primary spontaneous pneumothorax, a sharp decrease in the vital capacity of the lungs occurs, an increase in the alveolar-arterial oxygen gradient with the subsequent development of hypoxemia of varying severity. Hypoxemia develops against the background of ventilation-perfusion imbalance and the formation of a shunt from right to left. The clinical picture will directly depend on the severity of these disorders. Maintaining normal gas exchange does not allow the development of hypercapnia .

Rupture of lung tissue can occur in the area of pleural fusion during forced breathing or coughing. Secondary spontaneous pneumothorax develops when a pathological focus breaks into the pleural cavity in people suffering from destructive diseases of the pulmonary system ( lung gangrene , lung abscess , tuberculosis cavity , pulmonary infarction ). A similar process can occur in patients with histiocytosis X , neoplastic diseases of the mediastinum and lungs, chronic obstructive diseases ( bronchial asthma ).

Most often, right-sided pneumothorax is recorded, much less often - bilateral.

Signs and symptoms

Signs and symptoms may be absent or include:

cough, but not noticeable;
chest pain (not common);
difficulty breathing (fast and shallow);
low oxygen saturation;
pleural effusion (transudative type);
cyanosis (late sign);
increased heart rate.

It is a common misconception and pure speculation that atelectasis causes fever. A study of 100 postoperative patients followed by serial chest x-rays and temperature measurements showed that the incidence of fever decreased as the incidence of atelectasis increased. A recent review article summarizing the available published data on the association between atelectasis and postoperative fever concluded that there is no clinical evidence to support this suggestion.

Classification, types of pneumothorax

By distribution there are:

unilateral pneumothorax (right or left side);
bilateral pneumothorax.

According to the development of complications:

uncomplicated;
complicated (bleeding, emphysema, pleurisy).

By volume of air in the pleural cavity:

Small (less than 20% of the lung tissue is in a state of collapse). When X-rayed, a small pneumothorax appears as a small rim of air along the peripheral edge of the lung and, as a rule, does not require specific treatment in the absence of symptoms of respiratory failure.
C middle (the lung collapses to 1/2 the distance between the border of the heart and the lateral edge of the pleural cavity). Average pneumothorax requires treatment: with the help of repeated aspirations, a needle and a syringe with a volume of 50-100 ml, puncture of the pleural cavity is performed with air aspiration.
Big . For large pneumothorax, a special drainage tube must be inserted, focusing on the same anatomical landmarks as during aspiration. Help is to connect the drain to a siphon system, which functions as a one-way valve. You can immediately use a drainage tube equipped with a special valve.

Pneumothorax in connection with the environment is divided into:

Open pneumothorax . A pressure equal to atmospheric pressure is created in the pleural cavity due to communication between the pleural cavity and the external environment. The most important condition for the expansion of the lung is negative pressure in the pleural cavity, which is why with an open pneumothorax the lung collapses. In a collapsed lung, gas exchange cannot occur. Open pneumothorax completely shuts off the lung from the respiratory process, the blood ceases to be fully enriched with oxygen.
Closed pneumothorax . Communication with the external environment is completely absent. A small volume of gas enters the pleural cavity, which does not increase. Closed pneumothorax is considered the easiest, because air trapped in the pleural cavity can gradually resolve on its own. In this case, the lung does not expand.
Valvular pneumothorax . It develops during the formation of a valve structure that can allow air to pass in only one direction: from the external environment or the lung into the pleural cavity. The valve structure prevents the reverse flow of air and with each act of breathing there is an increase in pressure in the pleural cavity. Valvular pneumothorax is considered the most dangerous, because. in addition to shutting off the lung from the respiratory process, irritation of the nerve fibers in the pleura itself occurs, which inevitably leads to pleuropulmonary shock and displacement of organs in the mediastinum, which negatively affects their work and compression of large arteries and veins.

Pneumothorax can also be:

complete (the lung collapses completely);
parietal (the lung does not expand completely, a small volume of air is in the pleural cavity, is considered a “closed type”);
encysted (formed against the background of adhesive lesions of the visceral and parietal pleura, can be completely asymptomatic, and is considered less dangerous);
bilateral complete pneumothorax (due to critical impairment of respiratory function, if assistance is not provided in a timely manner, it can lead to a very rapid death).

Tension pneumothorax is a life-threatening condition caused by the accumulation of air entering under high pressure in the pleural cavity. The intense form most often develops as a result of traumatic injury to the chest, but can be a consequence of certain diseases of the respiratory system. In the absence of timely treatment, tension pneumothorax leads to death due to excessive compression of the mediastinal organs, heart and large vessels.

Traumatic pneumothorax develops after exposure to trauma to the chest area with subsequent rupture of the pleural layers (with knife or gunshot wounds). Traumatic pneumothorax can also develop with a closed chest injury: the pleural layer is damaged by a broken rib.

Spontaneous pneumothorax is not associated with iatrogenic treatment, diagnostic procedures, or trauma. Spontaneous collapse of the lung is read as idiopathic, spontaneous. The reasons can be very different ( cystic fibrosis , ankylosing spondylitis , Beck's sarcoidosis , etc.).