Leaving aside the indisputable role of endoscopy in the differential diagnosis of diseases manifested by obstructive syndrome, identifying their development with asthma – foreign bodies, neoplasms, congenital malformations of the tracheo-bronchial tree, etc., – it should be emphasized that opinions on the advisability of bronchoscopy in patients with asthma diverge.
Some authors, attaching great importance to the pathogenetic endobronchial inflammation and have already widely used bronchoscopic sanitation therapy since the 60s, indicate the high efficiency of the method. Others cautiously approach this issue, referring to the insecurity of bronchoscopy in bronchial asthma.
Along with this, from the standpoint of the modern understanding of bronchial asthma as chronic persistent inflammation of the respiratory tract, timely recognition and adequate treatment of the inflammatory process in the bronchi is extremely important. All this justifies the need for a clear definition of the role and place of bronchoscopy, the limits and prospects of its diagnostic and therapeutic capabilities in bronchial asthma.
Bronchoscopy is one of the most informative methods for diagnosing the pathological process in the lower respiratory tract. More than 30 years of experience in bronchological studies in asthma in children, which has a clinic of childhood diseases MMA named after THEM. Sechenov, allows you to formulate indications for bronchoscopy in bronchial asthma, in the determination of which we highlight the diagnostic and therapeutic aspects.
Diagnostic bronchoscopy is indicated:
1) with a therapeutically resistant obstructive syndrome, when it is necessary to exclude the presence of an additional obstruction of ventilation of an irreversible nature (foreign body, neoplasm, malformations of the tracheo-bronchial tree)
A child of 9 years old with clinical diagnoses: bronchial asthma, moderate course. Diagnosis after bronchoscopy: congenital malformation – double aortic arch, vascular stenosis of the trachea.
2) when coughing purulent-mucous sputum to clarify the nature and extent of endobronchial inflammation.
Therapeutic bronchoscopy for bronchial asthma aims to improve the ventilation function of the bronchi and pulmonary gas exchange and is carried out:
1) in patients with copious secretion, when there is a risk of stagnation of the contents of the bronchi and obstructive obstruction;
2) with lung atelectasis;
3) with purulent endobronchitis;
4) with therapy-resistant asthmatic status with a risk of asphyxiation.
Contraindications for bronchoscopy are acute inflammatory and infectious diseases, heart failure, disorders of the blood coagulation system, intolerance to anesthetics and drugs for general anesthesia. However, these contraindications can be relative if bronchoscopy is used when there is a risk of asphyxiation due to tracheobronchial obstruction (foreign bodies, tumors, congenital malformations of the lungs).
The use of bronchoscopy to diagnose bronchial asthma is always in great doubt, because visually detectable changes in the mucous membrane are nonspecific and are present in various obstructive and non-obstructive lung diseases. Our long-term observations indicate that a constant endoscopic sign of atopic bronchial asthma is edema of the bronchial mucosa; it is detected in 94% of the examined children. The greatest intensity of edema is noted in the onset of the disease, and, as histological studies have shown , exudation is not limited only to the mucous membrane itself, it penetrates deep into the bronchial wall, exfoliating muscle bundles. The color of the mucous membrane varies from pale with a slight cyanotic hue to bright red. Redness of the mucous membrane due to the accession of infection. Secretory disorders depend on the phase of the disease and were determined in 88% of patients. A visible narrowing of the lumen of the bronchi is observed in childhood in 70% of the examined children with asthma. The immediate cause of obstructive syndrome in young children should be considered swelling and hypersecretion .
Child 3 years old, diagnosis: bronchial asthma.
Child 6 years old. Diagnosis: asthma, post-attack period.
Thickening of bronchial spurs (the place of division of the bronchi) and marked folding of the mucous membrane, which are a manifestation of prolonged bronchospasm and thickening of the hyaline membrane of the bronchi, are characteristic of children who are long-term and seriously ill with bronchial asthma.
In addition to visual assessment, the results of laboratory studies of substrates obtained during endoscopy are decisive in clarifying the nature of endobronchitis. Detection in aspirate of a large number of neutrophils and pathogenic microbes in etiologically significant concentrations is in favor of an infection that stimulates bronchoconstriction and suffocation in bronchial asthma. Visually detectable diffuse edema, secretion of light pus without impurities, containing a large amount of eosinophils, Charcot-Leiden crystals, Curshman spirals, with some caution, allow talking about allergic, abacterial inflammation.
A difficult diagnostic problem is bronchial asthma in young children, since many diseases of the lower respiratory tract are accompanied by symptoms similar to bronchial asthma. Investigation of the function of external respiration and tests for hypersensitivity of the bronchi in this group of patients are difficult to perform and are not carried out in practice. This leads to a delayed diagnosis, delays the duration of anti-asthma therapy and worsens the outcome of the disease, which expands the indications for bronchoscopy in this category of patients.
To confirm or exclude the allergic etiology of endobronchial inflammation can bronchoscopy with a biopsy of the mucous membrane from the lower respiratory tract with a differential diagnostic purpose. According to our data, the most typical changes in bronchial asthma during histological and histochemical studies of bronchial biopsy samples were edema of the mucous membrane and muscle bundles, thickening and homogenization of the basement membrane, and its corrugation. Electron microscopic and histochemical studies noted an increase in the collagen content in the basement membrane. Our later studies showed that the cellular composition of mucosal infiltrate in bronchial asthma is characterized by a significantly larger number of IgE, IgA producing cells, degranulated mast cells and eosinophils per 1 mm2 than with non-obstructive bronchitis.
The main objectives of bronchoscopy in the treatment of bronchial asthma are:
1) the elimination of obstructive disorders of bronchial obstruction;
2) suppression of the activity of the infectious and inflammatory process in the lower respiratory tract by direct exposure to antibiotics on the etiologically significant microbial flora.
The tactics of the therapeutic effect, the volume and nature of the bronchological benefit depend on the phase of the course of the disease, the severity of the obstructive syndrome and the resulting respiratory failure. With exacerbation of bronchial asthma of mild to moderate severity, bronchial lavage (BL) is sometimes carried out – washing the bronchi with fractional injections of 15-20 ml (or more, depending on the age of the child) of warm saline into the lobar and segmental bronchi with subsequent aspiration of the contents. At the end of the procedure, the intrabronchial administration of antibiotics is logically justified if the role of the infectious factor in maintaining bronchoconstriction in suffocation is proved. Optimization of endobronchial antibiotic therapy is achieved by the original antibiotic administration regimen developed in our clinic. With purulent endobronchitis with a high degree of activity of bronchial infection, the course of treatment includes 3-5 procedures for 3 weeks.
The question of the effectiveness and safety of bronchoscopy in severe exacerbation of bronchial asthma, turning into an asthmatic status, seems extremely difficult. On the one hand, in the development of the terminal state and the genesis of death in patients with asthmatic status, acute respiratory failure, caused by blockage of the terminal bronchi by dense clots of mucus, comes to the fore. On the other hand, instrumental intervention at certain stages in this particular category of patients can be complicated by bronchospasm and laryngospasm, therefore there is a high risk of hypoxic disorders that pose a threat to the patient’s life. In this regard, the use of BL with prolonged attacks of suffocation and severe respiratory failure is a therapeutic dilemma, in which qualified anesthetists, resuscitators, bronchologists and clinicians experienced in treating patients with bronchial asthma should participate.
The accumulation of experience in the use of bronchoscopy in patients in status asthmaticus is still ongoing. Therefore, issues of increasing the effectiveness and safety of bronchoscopy, as well as clarifying the indications and contraindications for its use in asthmatic status, remain relevant.
Methodological aspects of bronchoscopy in bronchial asthma.
In order to increase therapeutic efficacy and reduce the risk of possible complications, certain principles must be followed.
Firstly, it concerns the choice of apparatus and method of anesthesia. With an exacerbation of a mild degree in school-age children who are emotionally stable and contact with a doctor, bronchoscopy can be performed under local anesthesia with a fibro-bronchoscope. With exacerbation of moderate to severe asthma, regardless of the patient’s age, the optimal conditions for the implementation of full bronchial lavage, good oxygenation and sufficient elimination of carbon dioxide throughout the procedure are ensured only with the use of a rigid injection bronchoscope and anesthesia with myo-relaxants with continuous mechanical ventilation.
Secondly, before the upcoming bronchoscopy, it is advisable to saturate the patient’s body with liquid, rehydration, as this helps soften the bronchial clots and increases the effectiveness of bronchoaspiration.
Patients in severe exacerbation and in asthmatic status need intensive medical and infusion therapy, since even a temporary weakening of bronchospasm and hypoxemia reduces the risk of bronchological intervention. Lavage of the bronchi in this group of patients is a resuscitation aid and should be carried out in the intensive care unit by experienced specialists.