Artificial pneumothorax

Artificial pneumothorax is the introduction of air into the pleural cavity, leading to the collapse of the affected lung.

Before the discovery of specific chemotherapeutic drugs, artificial pneumothorax was considered the most effective method of treating patients with destructive forms of pulmonary tuberculosis.

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Indications for artificial pneumothorax

When establishing indications for the imposition of artificial pneumothorax, a strictly individual approach is necessary. In each case, not only the stage of the process, the prevalence and nature of the lung damage are taken into account, but also the general condition of the patient, his age and other factors.

The main indications for the application of artificial pneumothorax:

• multidrug resistance of Mycobacterium tuberculosis:
• intolerance or hypersensitivity of patients to anti-tuberculosis drugs:
• some concomitant diseases or conditions that limit the administration of adequate chemotherapy in full and within the prescribed time frame.

Artificial pneumothorax is also indicated for patients who have undergone a 3-month course of chemotherapy, in the presence of unclosed cavities and decay cavities in infiltrative, focal, cavernous and limited hematogenous-disseminated pulmonary tuberculosis in the decay phase. In widespread dissemination, the imposition of artificial pneumothorax can lead to an exacerbation of the process and pneumopleurisy.

According to currently approved standards, treatment of pulmonary tuberculosis is carried out in stages. The tasks of artificial pneumothorax at each stage of treatment are different.

Indications for its use at stage 1 (in the intensive phase of chemotherapy in patients with newly diagnosed pulmonary tuberculosis):

• the impossibility of carrying out full-fledged chemotherapy due to drug resistance of mycobacterium tuberculosis or the presence of treatment-limiting side effects:
• lack of disease regression at the end of the intensive phase of treatment.

The purpose of using artificial pneumothorax at stage 1 is complete recovery of the patient in the shortest possible time without the use of surgical methods. Pneumothorax can be applied within 1-3 months from the start of chemotherapy. The duration of collapse therapy is 3-6 months.

At the 2nd stage (when the intensive phase of chemotherapy is extended to 4-12 months), this type of collapse therapy can be used as an additional method:

• in newly diagnosed patients with widespread tuberculosis, in whom there were no indications for the use of artificial pneumothorax during the intensive phase of treatment, but after chemotherapeutic treatment a positive effect was achieved (reduction in the severity of the process, reduction in the number of destruction cavities, partial resorption of inflammatory infiltration);
• in newly diagnosed patients who, due to inadequate therapy, developed secondary resistance to anti-tuberculosis drugs.

The use of artificial pneumothorax at stage 2 is an attempt to achieve complete recovery of the patient or a stage of preparation for surgery. Pneumothorax is applied 4-12 months after the start of chemotherapy. The duration of collapse therapy is up to 12 months.

At the 3rd stage (more than 12 months from the start of chemotherapy), after several ineffective, inadequate or interrupted courses of treatment with the development of multiple drug resistance with the presence of formed cavities, the main purpose of using pneumothorax is to prepare the patient for surgical treatment. Artificial pneumothorax in these patients is applied 12-24 months after the start of chemotherapy. The duration of collapse therapy is up to 12 months.

Sometimes artificial pneumothorax is imposed for urgent or vital indications (in cases of severe repeated pulmonary hemorrhages that do not respond to other treatment methods).

The localization of the process is important. Pneumothorax is often applied when cavities of destruction or caverns are localized in the apical, posterior and anterior segments of the lung. In this case, unilateral artificial pneumothorax is often used to achieve maximum effect.

The use of this method in case of bilateral lung damage is justified. Application of pneumothorax on the side of the larger lesion helps to stabilize the tuberculosis process on the opposite side and reverse the changes in the second lung. In case of bilateral processes, artificial pneumothorax is sometimes applied on the side of the smaller lesion as part of the patient's preparation for surgery on the opposite lung. In the presence of localized processes in both lungs, pneumothorax is sometimes applied on both sides simultaneously or sequentially to achieve the maximum effect of complex treatment. Such patients require a thorough examination to assess the state of the respiratory and cardiovascular systems. It is recommended to apply the second pneumothorax 1-2 weeks after the application of the first. The issue of the sequence of gas bubble formation is decided individually in each case. Most often, pneumothorax treatment begins on the side of the larger lesion.

The patient's age is of some importance. If necessary, artificial pneumothorax is used both in elderly patients and in adolescence.

Currently, along with medical indications, there are social and epidemiological indications. Given the high cost of reserve drugs for the treatment of forms of tuberculosis with multiple drug resistance, it is advisable to expand the indications for the use of artificial pneumothorax. The imposition of pneumothorax usually leads to the cessation of the release of mycobacterium tuberculosis in a short time, the patient ceases to be dangerous to others.

Preparation for artificial pneumothorax

No special preparation of the patient is required before pneumothorax is imposed. In some cases, the administration of painkillers and desensitizing drugs is permissible.

The mechanism of the therapeutic effect of artificial pneumothorax

The use of artificial pneumothorax in the treatment of pulmonary tuberculosis is possible due to the elastic properties of the lung. A decrease in elastic traction and partial collapse of the lung lead to the collapse of the walls and the closure of caverns or cavities of destruction. In hypotensive artificial pneumothorax with lung collapse by 1/3 of the volume and negative intrapleural pressure, the amplitude of respiratory movements decreases, the affected area of the lung is in a state of relative rest, while at the same time it participates in gas exchange. An increase in pressure in the pleural cavity leads to a redistribution of blood flow and a shift in the zone of active perfusion from the lower parts of the lungs to the upper ones. This helps improve the delivery of drugs to the areas of greatest lung damage. Artificial pneumothorax leads to the development of lymphostasis, slows down the absorption of toxins, enhances phagocytosis, stimulates fibrosis and encapsulation of foci, and also stimulates reparative processes, resorption of infiltrative-inflammatory changes, healing of decay cavities with the formation of linear or stellate scars in their place. The therapeutic effect of pneumothorax is also based on other neuroreflex and humoral mechanisms.

Artificial pneumothorax technique

There are more than 200 different modifications of devices for artificial pneumothorax. The principle of operation of most of them is based on the law of communicating vessels: liquid from one vessel enters another and pushes out air, which, entering the pleural cavity, forms a gas bubble.

For everyday work, the APP-01 device is recommended. It consists of two communicating containers (500 ml each) with divisions for determining the volume of air (gas meter). They are connected to each other and to the pleural cavity through a three-way valve. Moving liquid from one container to another results in the displacement of air into the pleural cavity.

A necessary part of any device for the imposition of artificial pneumothorax is a water manometer. It allows the doctor to determine the location of the needle (in the pleural cavity, in the lung, in the blood vessel) and the pressure in the pleural cavity before the introduction of gas, during its introduction and after the end of the manipulation.

The pressure in the pleural cavity during inhalation is normally from -6 to -9 cm H2O, during exhalation - from -6 to -4 cm H2O. After the imposition of pneumothorax and the formation of a gas bubble, the lung should be collapsed by less than 1/3 of its volume, while it can participate in the act of breathing. After the introduction of air, the pressure in the pleural cavity increases, but it should remain negative: from -4 to -5 cm H2O during inhalation and from -2 to -3 cm H2O during exhalation.

If during the pneumothorax the needle is inserted into the lung or into the lumen of the bronchus, the manometer registers positive pressure. When the vessel is punctured, blood flows into the needle. If the needle is inserted into the soft tissues of the chest wall, there are no pressure fluctuations.

The process of treating tuberculosis by applying artificial pneumothorax consists of several stages:

• formation of a gas bubble;
• maintenance of artificial pneumothorax with the help of constant insufflations;
• cessation of insufflation and elimination of artificial pneumothorax.

To impose pneumothorax, the patient is placed on the healthy side, the skin is treated with a 5% alcohol solution of iodine or a 70% solution of ethyl alcohol. The chest wall is punctured in the third, fourth or fifth intercostal space along the mid-axillary line with a special needle with a mandrel. After puncturing the intrathoracic fascia and parietal pleura, the mandrel is removed, the needle is attached to a manometer, and the location of the needle is determined.

Gas administration is prohibited if there are no pressure fluctuations synchronous with respiratory movements or if there is no certainty that the needle is in a free pleural cavity. The absence of pressure fluctuations may be caused by needle blockage with tissue or blood. In such cases, the needle should be cleared with a stylet and the position of the needle should be changed. Stable negative pressure in the pleural cavity, changing depending on the breathing phase, indicates the correct position of the needle in the pleural cavity. During the initial formation of a gas bubble, 200-300 ml of air is administered, with repeated ones - 400-500 ml. The initial and final readings of the manometer, as well as the amount of air administered, are recorded in the protocol. The entry is made as a fraction: the numerator indicates the pressure during inhalation, the denominator - the pressure during exhalation. Example: IP dex (-12) / (-8); 300 ml (-6) / (-4).

During the first 10 days after the imposition of artificial pneumothorax, insufflations are performed at intervals of 2-3 days; after the formation of a gas bubble and collapse of the lung, the intervals between insufflations are increased to 5-7 days, and the amount of gas administered is increased to 400-500 ml.

After pneumothorax is applied, its effectiveness, the feasibility of continuing treatment, and the possibility of correction must be assessed. These issues are resolved within 4-8 weeks from the moment of pneumothorax application. The optimal pulmonary collapse is considered to be the minimal decrease in lung volume at which pneumothorax provides the necessary therapeutic effect.

Variants of formed artificial pneumothorax

Complete hypotensive pneumothorax - the lung is uniformly collapsed by 1/3 of its volume, intrapleural pressure on inhalation is (-4)-(-3) cm H2O, on exhalation (-3)-(-2) cm H2O. Functional parameters are preserved.

Complete hypertensive pneumothorax - the lung is uniformly collapsed by 1/2 of its volume or more, intrapleural pressure is positive, the lung does not participate in breathing. It is used to stop bleeding.

Selective positive pneumothorax - collapse of the affected areas of the lung, intrapleural pressure (-4)-(-3) cm H2O during inhalation. (-3)-(-2) cm H2O during exhalation, the affected areas of the lung are straightened and participate in breathing.

Selectively negative pneumothorax - collapse of healthy parts of the lung without collapse of the affected areas, stretching of the cavity by adhesions, threat of rupture. Requires surgical correction.

Factors Affecting the Outcome of Artificial Pneumothorax

The main reason for the ineffectiveness of artificial pneumothorax is pleural adhesions and unions that prevent the full collapse of the affected areas of the lung and the healing of cavities. Adhesions are formed in the majority (up to 80%) of patients with pulmonary tuberculosis. The following types of pleural adhesions are distinguished: ribbon-shaped, fan-shaped, funnel-shaped, planar. Modern surgical technologies using videothoracoscopy allow for the effective and safe separation of such adhesions. Contraindications to videothoracoscopy are extensive (more than two segments) dense adhesions of the lung with a difficult wall (separation of adhesions is technically difficult).

Videothoracoscopic correction of artificial pneumothorax is performed under general anesthesia. A necessary condition for the operation is separate intubation of the bronchi with "switching off" the operated lung from ventilation. In some cases, artificial ventilation can be used instead of "switching off" the lung. A videothoracoscope is inserted into the pleural cavity and a thorough revision of the lung is performed. Adhesions and adhesions are separated using special instruments (coagulators, dissectors, scissors). The operation is completed by installing drainage (for 24 hours) to control hemostasis and aerostasis. The effectiveness of artificial pneumothorax correction is monitored using CT or X-ray examination.

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Collapse therapy

Four main methods are used in the treatment of pulmonary tuberculosis: anti-tuberculosis chemotherapy, homeostasis correction (regime, diet, symptomatic treatment), collapse therapy and surgical treatment. Collapse therapy is treatment using the creation of artificial pneumothorax or artificial pneumoperitoneum.

In recent years, there has been a decrease in the effectiveness of treatment with modern chemotherapeutic drugs due to the emergence of multidrug-resistant mycobacteria strains, so in some cases the treatment strategy must be revised. In case of intolerance to anti-tuberculosis drugs and multiple drug resistance of tuberculosis pathogens, the role of collapse therapy increases. In some cases, collapse therapy is the only method of treatment, sometimes it allows preparing the patient for surgery. In modern conditions, the economic factor should also be taken into account: collapse therapy methods are accessible, inexpensive and effective.

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Contraindications to artificial pneumothorax

There are general and specific contraindications to the imposition of artificial pneumothorax.

General contraindications:

• age over 60 years and under 10 years.
• respiratory failure grades II-III;
• chronic lung diseases (COPD, bronchial asthma);
• severe damage to the cardiovascular system, circulatory disorders;
• some neurological and mental illnesses (epilepsy, schizophrenia, drug addiction).

The clinical form of the disease, the prevalence and localization of the process, the presence of complications determine specific contraindications. It is technically impossible or ineffective to impose artificial pneumothorax in the presence of pronounced pleuropulmonary adhesions and the absence of a free pleural cavity, with the loss of elastic properties of the lung tissue as a result of inflammation with the development of fibrosis or cirrhosis. Such changes are detected in:

• caseous pneumonia;
• widespread disseminated pulmonary tuberculosis;
• fibrous-cavernous tuberculosis:
• cirrhotic tuberculosis;
• exudative or adhesive tuberculous pleurisy;
• tuberculous empyema of the pleura;
• tuberculosis of the bronchi;
• tuberculoma.

The presence of caverns with dense fibrotic walls, localization of caverns in the basal parts of the lung, large (over 6 cm in diameter) blocked, subpleurally located caverns are contraindications to the imposition of artificial pneumothorax.

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Complications of artificial pneumothorax

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Complications associated with the imposition of artificial pneumothorax

• traumatic lung injury (2-4%):
• subcutaneous or mediastinal emphysema (1-2%);
• air embolism (less than 0.1%).

Puncture of the lung during the application of artificial pneumothorax is a fairly common complication. The most dangerous consequence of such damage is tension traumatic pneumothorax, which often occurs in patients with severe emphysema and in some cases may require drainage of the pleural cavity. After a puncture of the lung with a needle, patients note hemoptysis, which usually goes away without special treatment.

Another complication is subcutaneous or mediastinal emphysema, which develops as a result of needle displacement and gas entering the deep layers of the chest wall, the interstitial tissue of the lung or the mediastinum. A small amount of air in the soft tissues usually resolves on its own. In some cases, pneumothorax is called "insatiable": despite frequent introduction of large volumes of air, it is quickly resolved. However, in most cases, these patients manage to create a gas bubble of sufficient size.

The most serious complication is air embolism caused by gas entering the blood vessels, which requires a complex of resuscitation measures. The patient suddenly loses consciousness, breathing becomes hoarse or stops. With a massive influx of air into the systemic circulation, especially into the coronary arteries or vessels of the brain, a fatal outcome may occur. The most effective method of treating massive air embolism is HBO.

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Complications arising from the maintenance of artificial pneumothorax

• pneumopleurisy (10-12%);
• rigid pneumothorax (5-7%);
• atelectasis (3-5%).

Pneumopleurisy develops with excessive gas administration or as a result of pathogenic microorganisms entering the pleural cavity. To eliminate pleurisy, fluid is evacuated from the pleural cavity, antibiotics are used in combination with glucocorticoids, and the frequency and volume of insufflations are reduced. In case of prolonged (more than 2-3 months) persistence of exudate, progression of the adhesive process with the formation of encapsulated pleurisy or empyema, treatment with pneumothorax should be interrupted.

Long-term collapse of lung tissue with irritation of the pleura by gas leads to a gradual loss of elasticity of the lung tissue and the development of pleural and lung sclerosis. Early signs of rigid pneumothorax: sinus pleurisy, limited mobility of the collapsed lung and thickening of the visceral pleura. When introducing a small volume of air into the pleural cavity, the manometer registers significant pressure fluctuations. In such cases, the intervals between insufflations should be lengthened and the volume of gas introduced should be reduced.

The development of atelectasis is associated either with “overblowing” or with damage to the bronchus; it is necessary to reduce the size of the gas bubble.

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