Diagnostic bronchoalveolar lavage

The idea of washing the bronchi to empty their contents belongs to Klin and Winternitz (1915), who performed BAL in 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, pulmonary gangrene, foreign bodies in the respiratory tract. Galmay in 1958 used massive lavage for postoperative atelectasis, aspiration of gastric contents and the presence of blood in the respiratory tract. Broom in 1960 performed bronchial lavage through an endotracheal tube. Then double-lumen tubes began to be used.

In 1961, QN Myrvik et al. used airway lavage in an experiment to obtain alveolar macrophages, which can be considered the birth of an important diagnostic method - bronchoalveolar lavage. The first study of lavage fluid obtained through a rigid bronchoscope was undertaken by RI Keimowitz (1964) to determine immunoglobulins. TN Finley et al. (1967) used a Meter balloon catheter to obtain secretions and study them in patients with chronic obstructive pulmonary disease. In 1974, HJ Reynolds and HH Newball were the first to obtain fluid for study during fibrobronchoscopy performed under local anesthesia.

Bronchoalveolar lavage is an additional test to establish the nature of the lung disease. Bronchoalveolar lavage is a procedure in which the bronchoalveolar region of the respiratory tract is washed with isotonic sodium chloride solution. It is a method of obtaining cells and fluid from deep within the lung tissue. Bronchoalveolar lavage is necessary 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 in patients with unclear or diffuse lung changes on chest radiography. Diffuse interstitial lung diseases present the greatest challenge to clinicians because their etiology is often unknown.

Indications for bronchoalveolar lavage are both interstitial infiltrations (sarcoidosis, allergic alveolitis, idiopathic fibrosis, histiocytosis X, pneumoconiosis, collagenoses, carcinomatous lymphangitis) and alveolar infiltrations (pneumonia, alveolar hemorrhage, alveolar proteinosis, eosinophilic pulmonitis, obliterating bronchiolitis).

Unclear changes may be of 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 studies. For example, even in normal lavage fluid, there is a high probability of detecting various disorders. In the future, bronchoalveolar lavage is potentially used to establish the degree of disease activity, to determine the prognosis and the necessary therapy.

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

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

The procedure is performed as follows. The bronchoscope is brought to the mouth of the subsegmental bronchus. Sterile isotonic sodium chloride solution, heated to a temperature of 36-37°C, is used as lavage fluid. The fluid is instilled 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, since alveolar macrophages stick to its walls.

Usually 20-60 ml of liquid are administered repeatedly, for a total of 100-300 ml. The volume of the resulting wash is 70-80% of the volume of the administered physiological 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 Nikiforov's mixture, and then stained according to Romanovsky. At least 500-600 cells are counted under a light microscope using oil technology, 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, as it contains cellular debris, a large number of neutrophils, intracellular enzymes and other elements of tissue decay. Therefore, to study the cellular composition of BAL, it is necessary to take a wash from the lung segments adjacent to the destruction.

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

Bronchoalveolar lavage is a simple, noninvasive, and well-tolerated test. There has been only one published report of a patient who died with acute pulmonary edema and septic shock following bronchoalveolar lavage. The authors speculate that the rapid deterioration of this patient's condition was due to a massive release of inflammatory mediators, resulting in pulmonary edema and multiple organ failure.

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

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