A method of carrying out bronchoalveolar lavage in patients with massive obstruction of bronchial secretions. Bronchoalveolar lavage in dogs and cats Indications and contraindications for BAL

Diagnostic capabilities of bronchoalveolar lavage

M.V. Samsonova

The introduction into clinical practice of fibrobronchoscopy and the technique of bronchoalveolar lavage (BAL), which makes it possible to obtain bronchial lavages (BS) and bronchoalveolar lavages (ALS), has significantly expanded the diagnostic capabilities in pulmonology. Thanks to the BAL technique, it became possible to use a whole range of cytological, bacteriological, immunological, biochemical and biophysical methods. These studies contribute to the correct diagnosis of oncological diseases and disseminated processes in the lungs, and also make it possible to assess the activity of the inflammatory process in the bronchoalveolar space.

BAL technique

BAL is performed with fibrobronchoscopy under local or general anesthesia. The bronchoscope is inserted into the lobar bronchus (usually the middle lobe of the right lung), the bronchial tree is flushed with a large amount of saline heated to 37 ° C. After washing, the solution is completely aspirated from the bronchial tree.

The bronchoscope is inserted into the mouth of the segmental bronchus, occluding it. A polyethylene catheter is passed through the biopsy channel of the bronchoscope and through it 50 ml of saline is injected into the lumen of the segmental bronchus, which is then completely aspirated. The resulting portion of fluid is a bronchial washout. Then the catheter is advanced 6-7 cm deep into the segment

Maria Viktorovna Samsonova -

doct. honey. sciences, head. lab. Pathological Anatomy Research Institute of Pulmonology, Roszdrav.

of the lung bronchus and fractionally inject 4 portions of 50 ml of saline, which are completely aspirated each time. These mixed portions constitute the bronchoalveolar lavage.

Research methods for BS and ALS

The main research methods for BS and ALS include biochemical and immunological examination of the supernatant, as well as the study of cell sediment. At the same time, the viability of BS and ALS cells, a cytogram are calculated, cytochemical studies of cells, as well as a cytobacterioscopic assessment are performed. Recently, a method has been developed for calculating the macrophage formula of ALS in various diseases of the bronchopulmonary system. The study of BAL fluid also allows one to assess the state of the surfactant system of the lungs by measuring the surface tension and studying the phospho-lipid composition of the surfactant.

The bronchial portion of the BAL fluid is used for qualitative and quantitative microbiological studies. In addition, changes in the cellular composition of BS can be used to determine the severity of the inflammatory response in the bronchial tree.

bronchial epithelium 5-20%

including

columnar epithelium 4-15% squamous epithelium 1-5%

alveolar macrophages 64-88% neutrophils 5-11%

lymphocytes 2-4%

mast cells 0-0.5%

eosinophils 0-0.5%

The normal cytogram of the alveolar portion of the BAL fluid (Fig. 1) is shown in table. 1.

Diagnostic value of the study of BS and ALS

The study of BS and ALS has the greatest diagnostic value for assessing the degree of inflammation in the tracheobronchial tree, with lung tumors and alveolar proteinosis.

Cytological examination of ALS has a high diagnostic value only in some lung diseases. Such nosologies include X histiocytosis, in which Langerhans cells appear (in their cytoplasm, characteristic X-bodies are determined by electron microscopy, according to the immunophenotype, these are CE1 + cells). With the help of ALS, it is possible to confirm the presence of pulmonary hemorrhage. The study of ALS is also shown when verifying alveolar proteinosis, which is characterized by the presence of extracellular substance (Fig. 2), which is well defined using light (PIC reaction) and electron microscopy. In this disease, BAL is not only a diagnostic, but also a therapeutic procedure.

Rice. 1. Normal cellular composition of ALS. Coloring according to Romanovsky. x400.

In pneumoconiosis, ALS studies can only confirm exposure to a dust agent. Specific diagnostics of beryllium disease can be carried out by studying the functional proliferative activity of ALS cells in response to the action of beryllium salts. With asbestosis in ALS, one can find asbestos bodies (Fig. 3) in the form of characteristic fibers - both extracellular and intracellular. These bodies are asbestos fibers with hemosiderin, ferritin, and glycoprotein aggregated on them; therefore, they stain well when carrying out the PIC reaction and Perls staining. It is extremely rare that asbestos bodies are found in persons who have had unprofessional contact with asbestos, while the concentration of such particles in ALS does not exceed 0.5 in 1 ml. Pseudo-asbestos bodies can also be found in ALS - with pneumoconiosis associated with exposure to dust from coal, aluminum, fiberglass, etc.

In patients with immunodeficiency states (in particular, HIV infection), BALF is the method of choice for detecting pathogens of infectious lung lesions. The sensitivity of BAL fluid in the diagnosis of pneumocystis infection (Fig. 4), according to some data, exceeds 95%.

In other diseases, the study of ALS is not highly specific, but it can provide additional information, which is evaluated in conjunction with clinical, radiological, functional and laboratory data.

With diffuse alveolar hemorrhage (DAH), which occurs in various diseases, free and phagocytosed erythrocytes and siderophages can be found in ALS (Fig. 5). ALS serves as an effective method for detecting DAK even in the absence of hemoptysis, when the diagnosis of this condition is extremely difficult. DAK should be differentiated from acute respiratory distress syndrome (ARDS),

in which siderophages also appear in ALS.

As part of the differential diagnosis of idiopathic fibrosing alveolitis (ELISA), cytological examination of ALS makes it possible to exclude other interstitial lung diseases. Thus, a moderate increase in the proportion of neutrophils and eosinophils in ALS does not contradict the ELISA diagnosis. A significant increase in the percentage of lymphocytes and eosinophils is not typical for ELISA, and in these cases, one should think about other alveolitis (exogenous allergic, medicinal or professional).

Cytological examination of ALS serves as a sensitive method in the diagnosis of exogenous allergic alveolitis (EAA). A high percentage of lymphocytes, the presence of plasma and mast cells, as well as “dusty” macrophages, in combination with anamnestic and laboratory data, makes it possible to diagnose EAA. The appearance of eosi-

Table 1. Normal cytogram of ALS

Cellular composition of ALS Non-Smoking Smokers

Cytosis, cell number x106 / ml 0.1-0.3> 0.3

Alveolar macrophages,% 82-98 94

Lymphocytes,% 7-12 5

Neutrophils,% 1 - 2 0.8

Eosinophils,%<1 0,6

Mast cells,%<1 <1

Rice. 2. Extracellular substance in ALS with alveolar proteinosis. Coloring according to Romanovsky. x400.

nophils or giant multinucleated cells (Fig. 6). Among the lymphocytes, cells with the immunophenotype C03 + / C08 + / C057 + / C016- predominate. It should be remembered that several months after the onset of the disease, along with T-suppressors, the number of T-helpers begins to increase. Additional research methods make it possible to exclude other diseases in which there is an increase in the proportion of lymphocytes in ALS, such as diffuse connective tissue diseases, medicinal alveolitis (LA), obliterating bronchiolitis with organizing pneumonia (OBOP), silicosis.

In sarcoidosis, an increase in the proportion of lymphocytes in ALS is also noted, and sarcoidosis is characterized by a

Rice. 4. Pneumocystis jiroveci in ALS. Coloring according to Romanovsky. x400.

Rice. 5. Siderophages in ALS. Perls staining. x100.

www.atmosphere-ph.ru

Rice. 6. EAA: increased proportion of eosinophils, neutrophils, lymphocytes in ALS, giant multinucleated cell. Coloring according to Romanovsky. x200.

Rice. 7. “Amiodarone lung” (LA): macrophages with foamy cytoplasm in ALS. Coloring according to Romanovsky. х1000, oil immersion.

Rice. 8. Lymphocytic type of ALS cytogram. Coloring according to Romanovsky. х1000, oil immersion.

the ratio of T-helpers and T-suppressors (С04 + / СЭ8 +) is higher than 3.5 (the sensitivity of this trait is 55-95%, specificity is up to 88%). Giant multinucleated cells (a type of foreign body cell) can also be found in ALS in patients with sarcoidosis.

Rice. 9. Neutrophilic type of ALS cytogram. Coloring according to Romanovsky. х1000, oil immersion.

With medicinal alveoli

max morphological changes in the lungs can be varied, often observed alveolar hemorrhagic syndrome or OBOP. An increase in the proportion of eosinophils and neutrophils may be noted in the ALS cytogram, but most often in PA

Table 2. Examples of the use of cytological analysis of ALS for differential diagnosis (according to OgeP M. et al., 2000)

Cytogram indicators

ALS and their assessment

Clinical examples of ALS cytogram

Cytosis, x104 / ml 29 110 100 20 64

Macrophages,% 65.8 18.2 19.6 65.7 41.0

Lymphocytes,% 33.2 61.6 51.0 14.8 12.2

Neutrophils,% 0.6 12.8 22.2 12.4 4.2

Eosinophils,% 0.2 6.2 7.0 6.8 42.2

Mast cells,% 0.2 1.0 0.2 0.3 0.4

Plasmacytes,% 0 0.2 0 0 0

CO4 + / CO8 + ratio 3.6 1.8 1.9 2.8 0.8

Bacterial culture - - - - -

The most probable diagnosis of sarcoidosis EAA LA ELISA OEP

Probability of correct diagnosis *,% 99.9 99.6 98.1 94.3 Not calculated

* Calculated using a mathematical model. Legend: OEP - acute eosinophilic pneumonia.

There is an increase in the percentage of lymphocytes, among which, as a rule, CD8 + cells predominate. A very high content of neutrophils in ALS occurs when taking the antidepressant nomifensine (the proportion of neutrophils can reach 80%, followed by a decrease and a simultaneous increase in the number of lymphocytes). With amiodarone LA (“amiodarone lung”), specific changes in ALS occur in the form of the appearance of a large number of “foamy” macrophages (Fig. 7). This is a very sensitive, but not very specific sign: the same macrophages can be found in other diseases (EAA, OBOP), as well as in patients taking amiodarone in the absence of alveolitis (amiodarone increases the content of phospholipids, especially in phagocytes).

In other cases, when BAL does not reveal highly specific signs of any disease, this method allows you to limit the differential diagnostic search (Tables 2 and 3) to the framework of a certain group of nosological units with one or another type of al-veolitis:

Lymphocytic (increase in the proportion of lymphocytes, Fig. 8): sarcoidosis, hypersensitivity pneumonitis, post-radiation pneumonia, ELISA, chronic infectious process in the lungs, AIDS, silicosis, Sjogren's syndrome, Crohn's disease, carcinomatosis, drug pneumopathies;

Neutrophilic (an increase in the proportion of neutrophils, Fig. 9): scleroderma, dermatomyositis, acute infectious process in the lungs, sarcoidosis in malignant course, asbestosis, medicinal al-veolite;

Eosinophilic (an increase in the proportion of eosinophils, Fig. 10): angiitis Cher-dzha-Strauss, eosinophilic pneumonia, drug alveolitis;

Mixed (Fig. 11): tuberculosis. histiocytosis.

When diagnosing lung cancer, the BAL method has the advantage of

Table 3. Cytological indicators of ALS in normal conditions and their changes in various pathologies (according to the data of OreP M. et al., 2000)

Alveolar macrophages Lymphocytes Neutrophils Eosinophils Plasmacytes Mast cells CD4 + / CD8 + ratio

Normal values

Non-smokers 9.5-10.5 * 0.7-1.5 * 0.05-0.25 * 0.02-0.08 * 0 * 0.01-0.02 * 2.2-2.8

85-95% 7,5-12,5% 1,0-2,0% 0,2-0,5% 0% 0,02-0,09%

Smokers 25-42 * 0.8-1.8 * 0.25-0.95 * 0.10-0.35 * 0 * 0.10-0.35 * 0.7-1.8

90-95% 3,5-7,5% 1,0-2,5% 0,3-0,8% 0% 0,02-1,0%

Noninfectious Diseases

Sarcoidosis T = = / T - = / T T / = / 4

EAA "Foamy" MF TT T = / T +/- TT 4 / =

Medicinal "Foamy" MF TT T T +/- TT 4 / =

alveolitis

IFA T T / TT T - T =

OBOP "Foamy" MF T T T - / + = / T 4

Eosinophilic T = TT +/- = / T 4

pneumonia

Alveolar "Foamy" MF T = = - N. d. T / =

proteinosis

Diseases of the connection - T = / T = / T - = / T T / = / 4

body tissue

Pneumoconiosis VKV (particles) T T = / T - = / T T / = / 4

Diffuse alveo- Coloring = / T T = / T - N. d. =

lary bleeding on Fe: +++

ARDS Coloring for Fe: + Т ТТ Т - = / Т 4 / =

Malignant tumors

Adenocarcinoma = = = - = =

Cancer lymphangitis T T / = T / = - / + T / = 4 / =

Hemoblastosis T T T - / + T 4 / =

And infections

Bacterial VKB (bacteria) = TT T - N. d. =

Viral VKB T T T - N. d. T / =

Tuberculosis VKV (mycobacteria) T = T - T =

HIV VKV T T T / = - N. d. 4

Designations: MF - macrophages, VKV - intracellular inclusions; indicator: T - increased; TT - significantly increased; 4 -decreased; = / T - not changed, rarely increased; T / = / 4 - can be increased, decreased or not changed; Т / ТТ - increased, rarely significantly increased; T / = - increased, rarely not changed; 4 / = - lowered, rarely not changed; = - not changed; - No; - / + - are rare; +/- meet; N. d. - there is no data.

* Data are presented in absolute numbers x104ml-1.

before sputum examination in relation to the detection of tumor cells, since the material can be

radiated from the lobe or segment where the tumor is localized. BAL is more likely to

to diagnose peripheral tumors, including bronchioloalveolar cancer (Fig. 12).

Rice. 10. Eosinophilic type of ALS cytogram, Shar-co-Leiden crystals. Coloring according to Romanovsky. x200.

Rice. 11. Mixed type of ALS cytogram: increased proportion of lymphocytes, neutrophils, eosinophils. Coloring according to Romanovsky. х1000, oil immersion.

Rice. 13. ALS in chronic bronchitis: the presence of cylindrical ciliated cells, neutrophils, an accumulation of coccal flora. Coloring according to Romanovsky. х1000, oil immersion.

Rice. 14. Mycobacterium tuberculosis in ALS. Coloring according to Tsilu-Nil-sen. х1000, oil immersion.

Rice. 15. Pseudomycelium of the fungus Candida albicans in ALS. Coloring according to Romanovsky. x200.

The cytobacterioscopic method makes it possible to identify and semi-quantitatively estimate the content of bacteria (Fig. 13), mycobacteria (Fig. 14) and fungi (Fig. 15) in ALS. These results (bacteria can be Gram differentiated) serve as the basis for the appointment of appropriate antibiotic therapy before obtaining the results of bacteriological research. In casuistic

Rice. 16. Significant increase in the number of neutrophils in ALS, numerous protozoa such as amoebas. Coloring according to Romanovsky. x200.

The study of ALS makes it possible to assess the degree of activity of the inflammatory process in infectious diseases and the effectiveness of the therapy. A low degree of inflammation activity is characterized by an increase in the proportion of neutrophils in ALS within 10%,

medium - up to 11-30%, high - more than 30%.

The use of histochemical methods for studying BAL fluid cells is possible with their high viability (more than 80%).

Conclusion

When assessing the changes identified in BS and UAS, certain rules should be followed and the following should be remembered:

The revealed changes are characteristic only for the studied segment, therefore, they must be treated with caution if the process is not diffuse;

The revealed changes are characteristic for a given moment in time;

Since the lungs are simultaneously affected by many factors (smoking, pollutants, etc.), it is always necessary to exclude the possibility of the influence of these factors on the development of pulmonary pathology.

Chernyaev A.L., Samsonova M.V. Pathological anatomy of the lungs: Atlas / Ed. Chuchalina A.G. M., 2004.

Shapiro N.A. Cytological diagnosis of lung diseases: Color atlas. T. 2.M., 2005.

Baughman R. P. Bronchoalveolar Lavage. St. Louis, 1992.

Costabel U. Atlas of Bronchoalveolar Lavage. L., 1998.

Drent M. et al. // Eur. Resp. Monograph. V 5. Mon. 14. Huddersfield, 2000. P. 63.

Books of the publishing house "ATMOSPHE

Amelina E.L. et al. Mucoactive therapy /

Ed. A.G. Chuchalin, A.S. Belevsky

The monograph summarizes modern ideas about the structure and functioning of mucociliary clearance, its disorders in various respiratory diseases, research methods; the main medicinal and non-medicinal methods of correcting mucociliary clearance in bronchopulmonary pathology are considered. 128 p., Ill.

For general practitioners, therapists, pulmonologists, medical students.

The idea of ​​flushing the bronchi to empty the contents belongs to Klin and Winternitz (1915), who performed BAL for experimental pneumonia. In the clinic, bronchoalveolar lavage was first performed by Yale in 1922 as a therapeutic manipulation, namely for the treatment of phosgene poisoning in order to remove abundant secretions. Vincente Garcia in 1929 used from 500 ml to 2 liters of fluid for bronchiectasis, gangrene of the lung, foreign bodies of the respiratory tract. Galmay in 1958 used massive lavage for postoperative atelectasis, aspiration of gastric contents and the presence of blood in the airways. Broom in 1960 performed bronchial lavage through an endotracheal tube. Then they began to use double-lumen tubes.

In 1961, Q.N. Myrvik et al. In the experiment, lavage of the airways was used to obtain alveolar macrophages, which can be considered the birth of an important diagnostic method - bronchoalveolar lavage. For the first time, the study of lavage fluid obtained through a rigid bronchoscope was undertaken by R.I. Keimowitz (1964) for the determination of immunoglobulins. T.N. Finley et al. (1967) used a balloon catheter Meter to obtain secretion and study it in patients with chronic obstructive pulmonary disease. In 1974 H.J. Reynolds and H.H. Newball first received fluid for examination during a fiberoptic bronchoscopy performed under local anesthesia.

Bronchoalveolar lavage is an additional study to determine the nature of the lung disease. Bronchoalveolar lavage is a procedure in which the bronchoalveolar region of the respiratory tract is flushed with isotonic sodium chloride solution. This is a method of obtaining cells and fluids from deeply located parts of the lung tissue. Bronchoalveolar lavage is essential for both basic research and clinical purposes.

In recent years, the frequency of pathological processes, the main symptom of which is increasing shortness of breath, has increased significantly.

Diagnostic bronchoalveolar lavage is indicated for patients who have unclear changes in the lungs, as well as diffuse changes, on chest x-ray. Diffuse interstitial lung diseases pose the greatest challenge to clinicians, as their etiology is often unknown.

Indications for bronchoalveolar lavage are both interstitial infiltration (sarcoidosis, allergic alveolitis, idiopathic fibrosis, histiocytosis X, pneumoconiosis, collagenosis, carcinomatous lymphangitis), and alveolar proteolytic infiltration (pneumonia, alveolar bronchitis)

Unclear changes can be infectious, non-infectious, malignant etiology. Even in cases where lavage is not diagnostic, its results can suggest a diagnosis, and then the doctor's attention will be focused on the necessary further research. For example, even in a normal lavage fluid, there is a high probability of detecting various violations. In the future, bronchoalveolar lavage is potentially used to determine the degree of disease activity, to determine the prognosis and necessary therapy.

Every year, bronchoalveolar lavage is increasingly used in the treatment of various lung diseases such as cystofibrosis, alveolar microlithiasis, alveolar proteinosis, lipoid pneumonia.

After examining all the bronchi, the bronchoscope is inserted into the segmental or subsegmental bronchus. If the process is localized, then the corresponding segments are washed; in diffuse diseases, fluid is injected into the bronchi of the middle lobe or reed segments. The total number of cells obtained by washing these sections is higher than by lavage of the lower lobe.

The procedure is performed as follows. The bronchoscope is brought to the orifice of the subsegmental bronchus. A sterile isotonic sodium chloride solution heated to a temperature of 36-37 ° C is used as a lavage liquid. The liquid is installed through a short catheter inserted through the biopsy channel of the bronchoscope, and immediately aspirated into a siliconized container. It is not recommended to use a regular glass cup, as alveolar macrophages adhere to its walls.

Usually 20-60 ml of liquid is injected repeatedly, only 100 - 300 ml. The volume of the resulting flush is 70-80% of the volume of the injected saline solution. The resulting bronchoalveolar lavage is immediately sent to the laboratory, where it is centrifuged at 1500 rpm for 10 minutes. Smears are prepared from the sediment, which, after drying, are fixed with methyl alcohol or a Nikiforov mixture, and then stained according to Romanovsky. In a light microscope using oil technology, at least 500-600 cells are counted, differentiating alveolar macrophages, lymphocytes, neutrophils, eosinophils and other cells.

Bronchoalveolar lavage taken from the site of destruction is not suitable for studying the pathogenetic mechanisms of the disease, since it contains cellular detritus, a large number of neutrophils, intracellular enzymes and other elements of tissue decay. Therefore, to study the cellular composition of ALS, it is necessary to take a wash from the lung segments adjacent to destruction.

ALS containing more than 5% of bronchial epithelium and / or 0.05 x 10 cells in 1 ml is not analyzed, since, according to studies by W. Eschenbacher et al. (1992), these indicators are typical for lavages obtained from the bronchi, and not from the bronchoalveolar space.

Bronchoalveolar lavage is a simple, non-invasive, and well-tolerated test. There was only one press report about a patient who died with acute pulmonary edema and septic shock due to bronchoalveolar lavage. The authors suggest that the lightning-fast deterioration of this patient's condition is associated with the massive release of inflammatory mediators, resulting in pulmonary edema and multiple organ failure.

Most of the reports of complications of bronchoalveolar lavage are associated with complications during bronchoscopy or depend on the volume and temperature of the injected fluid. Complications associated with BAL fluid include coughing during the procedure, and transient fever a few hours after the examination. The overall complication rate of bronchoalveolar lavage does not exceed 3%, rises to 7% when transbronchial biopsy is performed, and reaches 13% when an open lung biopsy is performed.

Microbiological and immunological studies of BS and ALS should be carried out in the same volume as the examination of sputum, and for similar indications. The greatest diagnostic value of BS and ALS is acquired when assessing the level of inflammation in the tracheobronchial tree, with lung tumors and with pulmonary proteinosis. At present, biochemical and immunological studies of the supernatant of BS and ALS are being carried out, as well as the study of the cell sediment. In this case, the viability of BS and ALS cells, cytogram are calculated, cytochemical studies of BAL cells are carried out, as well as cytobacterioscopic assessment. Recently, a method has been developed for calculating the macrophage formula of BAL fluid in various diseases of the bronchopulmonary system. The study of BAL fluid makes it possible to assess the state of the surfactant system of the lungs by measuring the surface tension and studying the phospholipid composition of the surfactant.

Bronchial portion of bronchoalveolar lavage used for qualitative and quantitative microbiological studies. In addition, changes in the cellular composition of BS can be used to determine the severity of the inflammatory response in the bronchial tree. According to the recommendations of the European Society of Pulmonology, the following composition of BS is characteristic of the norm:

It has a high diagnostic value only for some lung diseases. Interstitial diseases, in which the study of the cellular composition of ALS may be useful, include histiocytosis X, in which Langerhans cells appear, which have characteristic X-bodies in the cytoplasm, determined by electron microscopic examination (according to the immunophenotype, these are CD1 + cells). Using ALS, it is possible to confirm the presence of pulmonary hemorrhage. The study of ALS is indicated for the diagnosis of alveolar proteinosis, which is characterized by the presence of extracellular substance, which is well determined using light (PIC reaction) and electron microscopy. In this disease, BAL is not only a diagnostic, but also a therapeutic procedure.

With interstitial lung disease caused by inhalation of dust particles, using an ALS study, it is only possible to confirm exposure to a dust agent. Specific diagnostics of beryllium disease can be carried out by studying the functional proliferative activity of ALS cells in response to the action of beryllium salts. With asbestosis in ALS, you can find silicate bodies in the form of characteristic fibers - the so-called "glandular" bodies. Such asbestos bodies are asbestos fibers with hemosiderin, ferritin, glycoprotein aggregated on them. Therefore, they stain well when carrying out the PIC reaction and the Pearls stain. The described fibers in the flush can be detected both outside and intracellularly. It is extremely rare that asbestos bodies can be found in persons who have had unprofessional contact with asbestos, while the concentration of such particles in ALS will not exceed 0.5 ml. Pseudo-asbestos bodies, described for pneumoconiosis associated with exposure to coal, aluminum, fiberglass, etc., can also be found in ALS.

Bronchoalveolar lavage is the method of choice when it is necessary to obtain material from the lower parts of the lungs in patients with immunosuppressive conditions. At the same time, the effectiveness of the study for the detection of infectious agents has been proven. Thus, according to some data, the sensitivity of BAL in the diagnosis of pneumocystis infection exceeds 95%.

For other diseases, ALS study It is not highly specific, but it can provide additional information in a complex of clinical, radiological, functional and laboratory data. So, with diffuse alveolar bleeding in ALS, free and phagocytosed erythrocytes and siderophages can be detected. This condition can occur in various diseases, ALS is an effective method for detecting diffuse bleeding even in the absence of hemoptysis, when the diagnosis of this condition is extremely difficult. It should be remembered that diffuse alveolar bleeding should be differentiated from diffuse alveolar damage - adult respiratory distress syndrome, in which siderophages also appear in the lavage.

One of the most serious differential diagnostic problems- diagnostics of idiopathic fibrosing alveolitis. When solving this problem, cytological examination of ALS makes it possible to exclude other interstitial lung diseases. Thus, an increase in the proportion of neutrophils and eosinophils in ALS does not contradict the diagnosis of idiopathic alveolitis. A significant increase in the number of lymphocytes is not typical for this disease; in these cases, one should think about exogenous allergic alveolitis or other medicinal or professional alveolitis.

Cytological examination of ALS is a sensitive method in the diagnosis of exogenous allergic alveolitis. A high percentage of lymphocytes, the presence of plasma and mast cells, as well as foamy macrophages, in combination with anamnestic and laboratory data, make it possible to diagnose this nosology. Eosinophils or giant multinucleated cells may appear in ALS. Among the lymphocytes, cells with the CD3 + / CD8 + / CD57 + / CD16- immunophenotype prevail. However, it should be remembered that in the late phase of the disease, several months after the onset of the disease, along with suppressors, the number of T-helpers begins to grow. Other research methods make it possible to exclude other diseases in which there is an increase in lymphocytes - collagen diseases, drug pneumonitis, obliterating bronchiolitis with organizing pneumonia or silicosis.

With sarcoidosis an increase in the proportion of lymphocytes was also noted, however, it was shown that the ratio of helpers and suppressors (CD4 + / CD8 +) above 4 is typical for this nosological form (the sensitivity of this feature is, according to different authors, from 55 to 95%, the specificity is up to 88% ). Giant multinucleated cells of the "foreign body" type can also be found in ALS patients with sarcoidosis.

With medicinal alveolitis morphological changes in the lungs can be varied, often observed alveolar hemorrhagic syndrome or obliterating bronchiolitis with organizing pneumonia. In the cellular composition of ALS, an increase in eosinophils, neutrophils, lymphocytes is noted, sometimes a combined increase in these cells is possible. However, most often with medicinal alveolitis, an increase in lymphocytes is described, among which, as a rule, suppressor cytotoxic cells (CD8 +) predominate. An extremely high content of neutrophils occurs, as a rule, when taking the antidepressant nomifensine, especially in the first 24 hours. In this case, the proportion of neutrophils in ALS can reach 80%, followed by a decrease within 2 days to 2%, while the proportion of lymphocytes in the washout increases ... Similar observations are described for exogenous allergic alveolitis. When taking amiodarone and the development of drug alveolitis (the so-called "amiodarone lung"), specific changes in ALS occur, characterized by the appearance of a large number of foamy macrophages. This is a very sensitive, but not very specific sign: the same macrophages can be found in other diseases, including exogenous allergic alveolitis and obliterating bronchiolitis with organizing pneumonia. The same macrophages can be found in people taking amiodarone, but without the development of alveolitis. This is due to the fact that this substance increases the content of phospholipids, especially in phagocytes.

Lynelle R. Johnson DVM, PhD, Dip ACVIM (Internal Medicine)

University of California, USA

Basic Provisions

Tracheal collapse is most common in overweight, small breed dogs. Sometimes this pathology occurs in young large dogs.

Tracheal collapse most often occurs in the dorso-ventral direction. It is preceded by weakening and thinning of the cartilaginous rings of the trachea, as a result of which there is a prolapse of the posterior wall of the trachea into its lumen.

Collapse of the cervical trachea most often occurs on inspiration, and collapse of the thoracic trachea on expiration.

The best diagnostic method is visual inspection of the airways. Bronchoscopy can collect air samples from the deep airways.

The collapse of the trachea is a consequence of the irreversible pathology of the cartilaginous rings of the trachea. Treatment includes keeping the upper and lower airways in good condition.

Dogs with shortness of breath and severe cough associated with collapse of the cervical trachea are indicated for surgical intervention and replacement of the tracheal site with damaged cartilage rings.

Introduction

Tracheal collapse is quite common in veterinary practice. It causes cough and airway obstruction in small breed dogs. Sometimes this pathology occurs in young dogs of large breeds. Although the reasons for the development of tracheal collapse are not fully known, it is believed that this pathology is a consequence of congenital abnormalities, in particular, a genetic disorder of chondrogenesis. Tracheal collapse often develops due to chronic airway disease, cartilage degeneration, trauma and lack of innervation of the tracheal muscle (musculus trachealis dorsatis). Most often, the collapse of the trachea develops in the dorsoventral direction with the prolapse of a weak dorsal tracheal membrane into the lumen of the trachea.

Recognizing tracheal collapse in a clinical setting is fairly straightforward. Identifying the degree of difficulty in breathing in an animal, factors contributing to increased cough, and early intervention help to select the appropriate treatment for the patient, which improves the outcome of the disease and reduces the likelihood of severe complications.

Physiology and pathophysiology

The walls of the trachea are reinforced with 30-45 rings of hyaline cartilage. The ends of the cartilage formations are fastened on the dorsal side of the trachea to form a complete ring (Figure 1). The tracheal rings are connected to each other by annular ligaments. From the inside, the trachea is lined with pseudo-stratified, ciliated and columnar epithelium. In the upper respiratory tract, Goblet cells are found in the epithelial layer, producing mucus lining the epithelium. This mucus and the ciliated apparatus of epithelial cells are part of the lung's defense mechanism from damage.

The trachea is a unique structure: in its cervical region, the internal pressure is atmospheric, while in the thoracic region it is negative (corresponding to the pressure in the pleural cavity) (Figure 2a). On inspiration, the chest expands, and the diaphragm shifts towards the abdominal cavity. As a result, the volume of the pleural cavity increases, and the pressure in it decreases (Figure 26). A wave of reduced pressure is transmitted through the respiratory tract, as a result of which air enters the lungs. As you exhale, the pressure in the pleural space increases and the pressure gradient forces air out of the airways. In healthy animals, tracheal cartilage rings completely prevent significant changes in the diameter of the trachea during the phases of the respiratory cycle.

In dogs with tracheal collapse, the cartilage rings lose their elasticity and lose their ability to prevent changes in tracheal diameter during breathing due to pressure fluctuations. In some small breed dogs with tracheal collapse, an insufficient number of chondrocytes, a decrease in the content of chondroitin sulfate and calcium in the cartilage of the airways are detected. It is believed that the lack of glycoproteins and glucosaminoglycans causes a significant decrease in the amount of bound water in the cartilage tissue, drying out and thinning of the cartilage. The pathological changes found in the airway cartilage in dogs with tracheal collapse can be associated with both impaired chondrogenesis and degeneration of hyaline cartilage. The reason for the insufficient number of chondrocytes can be both genetic factors and deviations in nutrition.

In sick dogs, tracheal collapses occur in different parts of the trachea, depending on the phase of the respiratory cycle (Figure 2, b and c). Weakened cartilaginous rings in the cervical trachea lose their ability to withstand negative pressure during inspiration, which is why the trachea collapses (collapse) in the dorso-ventral direction. With repeated or permanent collapses, the cartilaginous rings are deformed, while stretching the dorsal wall of the trachea. This wall sags into the lumen, irritates the opposite wall, causing damage and inflammation of the tracheal epithelium. Due to inflammation, mucus secretion increases, and the number of cells that produce mucoid mucus increases. The amount of mucopurulent secretion can be so great that a film is formed, similar to that formed in diphtheria. All this causes a cough in the patient, disrupts the work of the ciliated apparatus of the respiratory tract and significantly increases the risk of infection.

Picture 1.

Endoscopic picture of a normal trachea. C-shaped cartilage rings are visible, the ends of which are connected by a dorsal tracheal membrane (in this photo- up). Blood vessels are visible through the respiratory epithelium.

In many sick dogs, collapses involve not only the cervical, but also the thoracic trachea, the main bronchi, and even the small airways. With intense exhalation or coughing, positive pressure appears in the pleural cavity, which is transmitted to the respiratory tract. Therefore, collapses of the thoracic airways usually occur during exhalation (Figure 2, c). It is not known whether the number of chondrocytes in the cartilage rings of the thoracic trachea is decreased in dogs with tracheal collapse. Sometimes in dogs, generalized collapses of the entire thoracic respiratory tract are also found.

Anamnesis and symptoms of the disease

Most often, tracheal collapse occurs in dogs of small and dwarf breeds: Chihuahua hua. Pomeranian, toy poodles, Yorkshire terriers, Maltese lapdogs and pugs. The age of dogs that first show signs of the disease ranges from 1 to 15 years. However, most often the disease manifests itself in adulthood. No sexual predisposition to the disease has been identified. Tracheal collapse is also rare in young large breed dogs such as golden retrievers or Labrador retrievers.

Most dogs with tracheal collapse have severe coughing fits for a long time. In general, pet owners describe this cough as "dry", "booming", gradually increasing. Owners often point out that the dog's coughing spells start after eating or drinking. As a result, some dogs begin to vomit, animals may choke on food, and even vomiting may occur. In some cases, such attacks of coughing develop so sharply that the owners have a situation that a foreign body has entered the dog's trachea. The cough gradually becomes paroxysmal and is accompanied by secondary damage to the airways. Shortness of breath develops, breathing rate increases, physical endurance decreases. With an increase in the load on the respiratory system (for example, due to physical activity, increased temperature or humidity of the environment), signs of respiratory failure are observed. Often, after intratracheal intubation, the severity of clinical symptoms increases. Exacerbation of symptoms can also be caused by physical exertion or a sharp jerk of the collar. Pet owners, fearing the deterioration of their pets, often limit their physical activity. As a result, many dogs become overweight and have a significant decrease in exercise tolerance. According to the author's observations, it is in overweight dogs that the load on the respiratory system is especially high. In obese animals, the severity of the clinical symptoms of tracheal collapse (especially cough) is very pronounced. However, according to the literature, among dogs undergoing surgery for tracheal collapse, only 9% were severely obese (4).

In the presence of collapse of the cervical trachea in dogs, inspiratory dyspnea is observed. The animal puffs heavily, drawing in air with difficulty. Auscultation reveals stridor and other large bubbling rales in the airways. Such auscultatory symptoms are characteristic of collapse of the cervical trachea and concomitant paralysis of the larynx. With the development of edema of the sacs of the larynx, symptoms of upper airway obstruction may appear. It manifests itself in the form of a transient "everting" cough and high inspiratory pressure.

Figure 2a. Sections of the trachea and the pressure that acts on individual sections of the respiratory tract: the cervical trachea is exposed to atmospheric pressure, and the thoracic- pleural.

Figure 26. On inspiration, the diaphragm expands and shifts back. As a result, the pressure in the pleural cavity becomes negative. A negative pressure wave is transmitted through the respiratory tract and causes atmospheric air to enter the lungs. In dogs with tracheal collapse, the trachea loses its elasticity and ability to withstand pressure changes. As a result, when inhaling, it falls in the dorso-ventral direction.

Figure 2c. With forced expiration or coughing, pleural pressure becomes positive. This allows the airway to open in the chest. However, if the cartilage rings are not rigid enough, collapse occurs.

When a dog develops chronic bronchitis, aggravated by collapses of the cervical or thoracic trachea, the cough becomes hard, becomes permanent, and is accompanied by sputum production. Rarely, dogs with collapsed cervical or thoracic trachea have transient hypoxemia leading to syncope. These fainting spells often occur during coughing fits. However, in some dogs syncope is secondary due to the development of pulmonary hypertension and hypoxia.

Clinical examination

Dogs with collapsed trachea appear healthy at rest. Even during bouts of coughing, their condition is not alarming. Any dog ​​showing signs of systemic illness should be examined for abnormalities that cause coughing fits (heart failure, pneumonia, respiratory neoplasms). A thorough general clinical examination will clarify the cause of the cough and identify concomitant diseases.

Figure 3.

Respiratory X-ray of a 10-year-old Yorkshire Terrier on inspiration. The dog had coughing fits, shortness of breath, cyanosis for 2 months. The radiograph obtained in the lateral projection shows the collapse of the cervical trachea, extending up to the entrance of the trachea into the chest. The thoracic aorta is slightly dilated. X-ray image courtesy of Dr. Anne Babr)

The examination of the respiratory system should begin with careful auscultation and careful palpation of the trachea and larynx. The presence of palpable sacs of the larynx indicates a dysfunction of this organ. According to some researchers, this dysfunction develops in 20-30% of dogs with tracheal collapse (5, 6). Turbulization of the air flow in the narrowed part of the trachea leads to the generation of characteristic sounds that are heard during auscultation of the trachea. In some dogs with collapsed trachea, the trachea is extremely sensitive, so extreme care should be taken to prevent stimulation of an attack during examination. Palpation of the trachea in some cases of collapse reveals excessive compliance or softness of its cartilaginous rings.

In dogs with uncomplicated large airway collapse, breathing sounds in the lungs are often unchanged. However, it can be difficult to conduct an auscultatory examination in such cases due to shortness of breath, rapid breathing and obesity (as a result of which the respiratory sounds are muffled). In addition, strong noises in the upper airways drown out weak bronchoalveolar sounds. Pathological noises in the lungs (wheezing and whistling) often make it possible to diagnose the nature of the pathology. Wheezing in the lungs usually indicates the passage of air through fluid-filled alveoli or mucus-blocked airways. Mild wheezing on inspiration may be a sign of pulmonary edema; harder and louder wheezing is common in dogs with pneumonia and pulmonary fibrosis. Whistles are longer sounds, usually heard on exhalation. They are typical for animals with chronic bronchitis. A characteristic sign of the defeat of the small airways is also the tension of the abdominal press during exhalation.

Small breed dogs often have heart valve failure. As a result, heart murmurs make it especially difficult to diagnose the cause of cough with auscultation. Usually, tachycardia is observed with congestive heart failure. In diseases of the respiratory tract, the heart rate usually persists, but severe sinus arrhythmia develops. Under stress on the respiratory system, and in such animals, tachycardia may appear, which significantly complicates the diagnosis. It is especially difficult to diagnose the disease in small dogs suffering from congestive heart failure and pathologies of the trachea and bronchi. In such cases, an X-ray examination is indicated.

Diagnostics

Although the diagnosis of tracheal collapse can be made on the basis of anamnesis and clinical symptoms, a general clinical examination of the sick animal is necessary to determine concomitant diseases and prescribe individual treatment. For the diagnosis of concomitant diseases, it is recommended to do a complete blood count, including the determination of the number of cells and biochemical parameters of serum, and a urinalysis.

Imaging methods

To clarify the diagnosis of collapse of the trachea and identify concomitant diseases of the lungs and heart, the use of radiography is shown. Usually, radiographs are obtained in standard projections, but radiographs in the ventrodorsal projection during inhalation and exhalation are better. On radiographs obtained with a full breath, collapse in the cervical trachea is clearly visible. In this case, the thoracic region of the trachea can be expanded (Figure 3, 4a). Collapse of the main bronchi, thoracic trachea, or a combination is usually seen on full expiratory radiographs. The cervical part of the trachea is inflated at the same time (Figure 46).

The accuracy of the diagnosis increases if a coughing attack is provoked during an X-ray examination. Unfortunately, it is difficult to correctly interpret airway dynamics from static radiographs. According to some studies, X-ray diffraction patterns reveal tracheal collapse in only 60-84% of cases (4, 5). Radiographic imaging of the trachea is often difficult due to overlapping images of the esophagus or cervical muscles. In such cases, during X-ray examination, it is effective to use a non-standard projection, from the bottom up. This projection allows you to identify dormant areas in the cervical trachea, although it can be difficult to correctly direct the X-ray beam. During mass fluoroscopic examinations in dog kennels, cases of transient airway collapses can be detected. The same method can be used to identify the phase of the respiratory cycle at which collapses develop.

Figures 4. Respiratory radiographs of a 13-year-old Poodle with long-term coughing fits.

4a. Inspiratory X-ray. The cervical and thoracic trachea are free. The main bronchi are also free, although the diameter of the left bronchus is somewhat smaller.

46. ​​Exhalation X-ray. The collapse of the thoracic trachea is clearly visible. The collapse also involves the main bronchi and airways distal to the sternum.

Recently, ultrasound has been used to diagnose tracheal collapse (7). When the ultrasound source is located on the neck, it is possible to examine the diameter of the lumen of the cervical trachea and document the dynamics of its change during the respiratory cycle. In cases where it is impossible to do fluoroscopy, ultrasound is prescribed as the most appropriate method for diagnosing tracheal collapses. Unfortunately, ultrasound is usually only effective for cervical tracheal collapse. In addition, it does not allow the diagnosis of concomitant inflammation and infection of the lower respiratory tract.

In small-breed dogs, due to their physique or obesity, it can be difficult to detect abnormalities in the tissues of the lungs and heart on x-rays. For example, in overweight dogs, fatty deposits in the chest and mediaspia can give a misleading picture of infiltrates and lungs. Accumulation of fat in the pericardium and limited lung mobility associated with obesity can be misleading about the presence of cardiomegaly. Thus, changes in interstitial density and heart size in dogs with tracheal collapse should be interpreted carefully. If an animal has a heart murmur, special attention should be paid to the examination of the heart contour - hypertrophy of the left atrium is possible due to compression by the left bronchus. Ventrolorsal radiographs can not only examine the condition of the dog's heart and lungs, but also assess the degree of its obesity. The owner of the dog should be sure to point out the thick fat layer covering the chest. This will help convince him of the need to reduce the animal's weight.

Obtaining samples from the respiratory tract

To obtain samples from the respiratory tract, either flushing (lavage) of the trachea or bronchoscopy is used. Both of these procedures require anesthesia. However, it is very useful to conduct them, as it allows you to obtain fluid samples from the lower parts of the respiratory tract for cytological or bacteriological examination. Using these methods, it is possible to diagnose airway infection and assess the contribution of inflammatory reactions to the observed clinical symptoms. A thorough examination of the upper respiratory tract is necessary before lavage or bronchoscopy is performed. Upper airway obstruction can exacerbate symptoms associated with tracheal collapse. When examining the upper respiratory tract, special attention should be paid to the state of the larynx function, the length of the soft palate and the absence of swelling of the sacs of the larynx.

For tracheal lavage, it is most convenient to use the transoral approach (see Protocol 1). With this approach, there is less risk of damage to the cartilaginous rings of the trachea and mucous membranes. To facilitate intubation, it is best to use general anesthesia or strong salative drugs. Thin sterile intratracheal probes should be used to minimize mucosal irritation. When passing the probe into the trachea, care must be taken not to contaminate the samples obtained with bacterial microflora and cells of the mucous membrane of the upper respiratory tract. The probe cuff is not required for this procedure. The obtained lavage samples must be sent for bacteriological cultivation to detect aerobic bacteria. Cultures for Mycoplasma infection can also be done.

The interpretation of the results of bacteriological tests is greatly facilitated after a cytological examination of the lavage. For example, in healthy dogs, the pharynx is not sterile, which is why bacteriological examination in lavage crops can reveal the growth of bacteria (8) (Table 1). When detecting squamous cells of the oral cavity and bacteria in the lavage Simonsiella in the course of histological examination, the growth of these bacteria and mycoplasmas can also be expected in bacteriological cultures. Bacteriological cultivation of lavage in dogs with tracheal collapses usually reveals many bacteria of different species (Table 1). However, the role of bacterial infection in the development of clinical symptoms of this disease is still unclear.

Results of bacteriological study of microflora of healthy dogs and dogs with tracheal collapses

Severity of tracheal collapse

Grade I	The cartilaginous rings of the trachea keep the ring structure almost normal. There is a slight deflection of the dorsal tracheal membrane into the lumen of the trachea, which reduces the diameter of this lumen by no more than 25%.
Grade II	The cartilage rings are flattened. Due to the deflection of the stretched dorsal tracheal membrane, the diameter of the tracheal lumen is reduced by about 50%.
Grade III	The cartilaginous rings are very flattened. The muscles of the tracheal membrane touch the inner part of the rings. The diameter of the lumen of the trachea is reduced by 75%.
Grade IV	The muscles of the tracheal membrane completely overlap the lumen of the trachea. In severe cases, the tracheal lumen becomes double.

To obtain samples of the microflora that populates the lower respiratory tract, it is better to use bronchoscopy. With the help of a bronchoscope, samples can be obtained without the risk of contamination with bacteria from the upper respiratory tract. In addition, bronchoscopy can confirm the diagnosis of tracheal collapse in cases where X-ray and fluoroscopy data do not allow a firm conclusion to be made. Bronchoscopy makes it possible to directly assess the location and degree of weakening of the damaged cartilaginous tracks of the trachea or bronchi (Table 2). which characterize the severity of the collapse of the trachea, which is especially important in preparation for surgery. Bronchoscopy also allows you to investigate the dynamics and nature of damage, identify areas of inflammation and irritation of the mucous membranes, confirm or deny the diagnosis of collapse of the thoracic trachea. Thus, bronchoscopy is one of the most effective methods for assessing the role of airway disease in the development of pulmonary failure.

Protocol for obtaining tracheal lavage in dogs

- Give the dog an oxygen mask for preoxygenation.

- Introduce a sedative to examine the structure and function of the upper respiratory tract. Observe the functioning of the larynx while breathing. Normally, in dogs, arytenoid cartilage moves to the side during inhalation.

— Intubate the animal with a thin sterile endotracheal probe. During intubation, ensure that the probe does not touch the pharynx while entering the airway.

- Insert a thin polypropylene sterile catheter into the airway through the tube to the level of the sternum (you can use a tube for parenteral nutrition). The length of the catheter should be such that the level of the 4th rib can be reached.

- Introduce 4-6 ml of sterile saline through the catheter using a syringe. While aspirating the injected fluid, induce a cough or massage the dog's chest to increase the amount of lavage being sucked out.

- Repeat saline infusion and aspiration if necessary. You need to get 0.5-1 ml of lavage. Lavage should be sent for bacteriological (including determination of the presence of mycoplasmas) and cytological examination.

- Before completing the procedure, inject 1 ml of 1% lidocaine solution into the tracheal catheter. This will weaken the cough reflex.

- If necessary, place the patient in an oxygen chamber.

When preparing dogs for airway examinations, they must be preoxygenated for 5 minutes. before starting anesthesia. A variety of methods can be used for anesthesia. The purpose of anesthesia in this case is to prevent a cough reflex and damage to the endoscope during bronchoscopy. When choosing an anesthesia method, one should focus on the general health of the dog and the characteristics of the anesthetic used (its side effects). Since most dogs with tracheal collapse are small breeds, brochoscopes no larger than 4.5-5 mm are preferred. Sometimes the dog is so small that it is impossible to use anesthetic gas anesthesia and it is impossible to pass a bronchoscope through the intratracheal tube. In this case, the dog should be extubated during bronchoscopic examination of the trachea and lower respiratory tract when using anesthetic gas anesthesia.

For bronchoscopy, the dog should be laid with its back up, and a small pillow should be placed under the chin. To fix the mouth in an open position during the procedure, 2 large mouth dilators are used. First, a bronchoscope is used to examine the larynx and upper respiratory tract. After its introduction into the trachea, the degree and dynamics of its collapse is determined (Figure 5). With the help of marks on the remaining part of the bronchoscope outside, it is possible to determine the length of the collapsed section of the trachea or the number of cartilaginous rings, the structure of which is disturbed. After the introduction of a bronchoscope into the retrosternal part of the respiratory tract, the main bronchi are examined. Healthy bronchi are open and have a circular or elliptical section

(Figure 6). The diameter of the airways during breathing should change slightly, and the amount of secretions in them should be minimal. In dogs with generalized airway collapses, the shape of these airways is variable. In addition, they clearly show the closure of these lumens even with unforced breathing (Figure 7).

Bronchoalveolar lavage (BAL) should be collected from all dogs undergoing bronchoscopy. It is obtained with the help of a bronchoscope and sent for examination in order to detect infection with bacteria or mycoilases, as well as signs of inflammation. Based on the results of bacteriological and histological examination of the obtained BAL fluid, the animal can be prescribed appropriate antibiotic therapy and / or anti-inflammatory treatment (9). To obtain BAL fluid, a bronchoscope is carefully inserted into the small bronchi and 10-20 ml of sterile saline is injected through its biopsy canal. Suction of the injected liquid can be carried out manually, with special care, or by using a mechanical suction with a sample trap. Usually it is possible to suck out 40-60% of the volume of the injected fluid. Normally, BAL contains about 300 leukocytes per ml, of which 70-80% are alveolar macrophages, 5-6% are lymphocytes. 5-6% for neutrophils and 5-6% for eosinophils. A sign of an inflammatory reaction is a significant increase in the number of neutrophils. The fact of infection can be established on the basis of the detection of septic neutrophils and the presence of phagocytosed bacteria in the cells.

Figure 5. II-III degree. A sterile rubber catheter was used to provide oxygen during bronchoscopy. The cartilaginous rings are flattened, as a result of which the dorsal part of the trachea (under the mark in the picture) is stretched.

Image courtesy of JeffD. Bay, DVM. MS, University of Missouri, Columbia. USA

Bronchoscopy in dogs with tracheal collapse is a risky procedure. The risk of complications is especially high in obese dogs, which are characterized by hypersensitivity of the trachea. To reduce the risk of complications, the animal should be removed from anesthesia slowly, providing an oxygen-enriched environment. Before removing the bronchoscope, 1 ml of 1% lidocaine solution can be injected into the distal trachea. This will weaken the cough reflex.

Drug treatment

If the dog has severe dyspnea associated with airway obstruction, the stress of the diagnostic test should be minimized. In such cases, to remove the animal from a dangerous state, it is necessary to place it in an oxygen chamber and apply mild sedatives. For example, subcutaneous administration of butofanol (0.05-1 mg / kg) and acepromazine (0.01-0.1 mg / kg) every 4-6 hours allows not only to calm the dog down, but also to stop his coughing attack. It should be noted that the use of these drugs in combination requires some caution, as it can cause a sharp drop in blood pressure. At the beginning of use, the minimum dosage of drugs should be used to determine the sensitivity of this animal to them. If undesirable consequences do not occur, in the future, if necessary, the dosage can be increased. If the dog has severe tracheal inflammation or laryngeal edema, a single dose of a short-acting, anti-inflammatory corticosteroid should be given.

Long-term therapy for tracheal collapse in dogs should be aimed at weakening those factors that can provoke an increase in the clinical symptoms of the disease. Unfortunately, there are no specific methods of treating metabolic disorders in the cartilaginous tissue of the tracheal rings, so the risk of exacerbation of the disease in a sick dog persists throughout its life. Antibiotic therapy should be given if respiratory tract infection is detected. The choice of antibiotics is carried out on the basis of determining the sensitivity of the sown microflora of the patient to them. If infection with mycoplasma is detected, antibiotics that are effective against microorganisms lacking a cell wall should be used. Doxyiclin, chloramphenicol and enrofloxacin are most effective in this case. A 7-10 day course of antibiotics is usually sufficient to sterilize the airways, but in the presence of pneumonia, the duration of antibiotic therapy can be from 3 to 6 weeks.

With severe tracheitis, short-term treatment with corticosteroid drugs is necessary. Usually, the patient is given prednisone or prednisolone at doses of 0.5 mg / kg / day for 3-7 days. If the dog has chronic bronchitis against the background of tracheal collapses, a longer course of corticosteroid therapy is prescribed. The drugs are used in high dosages. After the inflammation has been relieved and the infection has been eliminated, cough medications are prescribed. Its suppression is necessary to interrupt the cycle of repeated airway injuries. Usually, suppression of cough in dogs with tracheal collapse requires narcotics. It is possible to effectively suppress cough with the help of hydrocolon (0.22 mg / kg 2-3 times a day) or butorphanol (0.55-1.1 mg / kg if necessary), used per os(ten). At the beginning of the course, the dosage of these drugs is selected for each dog individually in such a way as to achieve the maximum suppression of cough noreceptors do not belong to bronchodilators, but they cause dilatation of small airways and facilitate air exchange in them during exhalation. As a result, the likelihood of collapse of the thoracic trachea is reduced. Special pharmacokinetic studies of various forms of theophylline have shown that two long-acting theophylline preparations produced by different companies ensure the maintenance of a sufficiently high concentration of the drug in the blood of dogs for a long time. Conventional forms of theophylline can also be effective, but their effectiveness is much lower than that of the aforementioned sustained-release drugs. For tracheal collapse in dogs, β-adrenergic receptor agonists are also used: terbutaline (1.25-5 mg / kg<гол- 2-3 раза вдень) и альбутерол (50 мкг/кг 3 раза в день). Следует помнить, что применение бронхорасширяющих средств любого типа может привести к побочным эффектам, например, повышенной нервозности и возбудимости животных, тахикардии, желудочно-кишечным расстройствам.

Diet therapy is indicated for all dogs with tracheal collapse. Losing body weight, for example, significantly reduces the stress on the respiratory system. To achieve this goal, animals are usually switched to ready-made, low-calorie diets that provide approximately 60% of the energy requirements of healthy dogs. The ideal rate of weight loss (2-3% of body weight per week) allows the owner to quickly normalize the dog's weight. It is also helpful to gradually increase the animal's physical activity - this makes it easier and faster to achieve normal body weight. It should be noted that it is better to reduce physical activity in hot and humid weather to a minimum, and replace the collar with a harness. This will avoid a sudden exacerbation of the disease.

Surgery

In case of collapses of the cervical trachea, prosthetics of the affected cartilage rings are effective. Surgical intervention is indicated in cases where therapeutic treatment is ineffective or, due to respiratory failure in animals, weakening of conditioned reflexes and fainting are observed. Surgical intervention significantly weakens the clinical symptoms: the cough disappears, breathing becomes freer. One study found that dog owners were generally happy with the outcome of surgery, even if postoperative laryngeal paralysis required a tracheostomy.

For dogs with upper airway obstruction, surgical removal of the cause of the obstruction is necessary. For example, shortening the soft palate and freeing the arytenoid cartilage of the larynx has been shown to alleviate clinical symptoms in tracheal collapses.

Tracheal collapses are common in small breed dogs and require long-term treatment. Sick animals are shown to reduce body weight and use anti-cough drugs. In each specific case, it is also important to identify and eliminate concomitant diseases of the upper and lower respiratory tract, complicating the course of collapses of the trachea.

And a therapeutic medical procedure, involving the introduction of a neutral solution into the bronchi and lungs, its subsequent removal, the study of the state of the respiratory tract and the composition of the extracted substrate.

In the simplest cases, it is used to remove excess mucus in the airways and then study their condition. Liquid removed from the patient's lungs can also be the subject of research.

Technique

BAL is performed under local anesthesia by introducing an endoscope and special solutions through the nasal airways (and less often through the mouth). The patient's spontaneous breathing is not impaired. The researcher is gradually studying the state of the bronchi and lungs, and then the washings: in the microbiological, the causative agents of tuberculosis, pneumocystosis can be identified; with biochemical - changes in the content of proteins, lipids, disproportions in the ratio of their fractions, disturbances in the activity of enzymes and their inhibitors.

Lavage is made on an empty stomach, at least 21 hours after the last meal.

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Diagnostic value

Most important for the diagnosis of sarcoidosis (mediastinal form with no radiological changes); disseminated tuberculosis; metastatic tumor processes; asbestosis; pneumocystosis, exogenous allergic and idiopathic fibrosing alveolitis; a number of rare diseases. It can be successfully used to clarify the diagnosis and with limited pathological processes in the lungs (for example, malignant tumors, tuberculosis), as well as with