RATS - additional respiratory sounds due to narrowing of the airways or the presence of pathological contents in them. There are wet and dry rales.
Wet rales are formed as a result of foaming by a stream of inhaled air of a fluid (exudate, transudate, blood, etc.) located in the airways or in pathological cavities of the lungs. As a rule, they are better heard in the inspiration phase; depending on the caliber of the bronchi or the volume of the cavities containing the liquid, they can be small-, medium- and coarse-bubble. Small bubbling rales resemble the noise of gas bubbles in a glass of sparkling water, medium and large bubbles are the sound of bursting air bubbles blown into the water through a straw, respectively, with a very narrow or wider clearance. Small bubbling rales are most often heard with focal pneumonia, pulmonary infarction, beginning pulmonary edema (congestive rales), sometimes in the acute phase of bronchiolitis. With pneumonia, wheezing is heard over a limited area of the lung, does not disappear and does not change after coughing and changing body position; with pulmonary edema, moist rales are determined on both sides or over the lowest parts of the lungs, depend on the position of the body, disappear after the application of diuretics. With bronchiolitis, wheezing is sonorous, scattered, changes after coughing, usually combined with dry wheezing. Mid-bubbling rales are determined over pathological cavities that are small (lung abscesses, bronchiectasis), as well as with developed pulmonary edema, when the transudate reaches the level of small and medium bronchi. The so-called cracking rales, resembling the cracking of torn matter, which are more often caused by the sticking of collapsed alveolar passages in the foci of pneumosclerosis, around the site of atelectasis, in the areas of pulmonary fibrosis (with sarcoidosis, lung beryllosis, etc.), are also usually referred to as medium bubbling rales. Coarse bubbling rales are heard over relatively large cavities containing fluid and connected to the bronchus (cavity, abscess), as well as with the accumulation of transudate or liquid sputum in the lumen of large bronchi.
Dry rales always indicate a narrowing of the lumen of the bronchi, which may be due to deformation of their walls (with pneumosclerosis), compression by the tumor, but often inflammatory or allergic edema of the mucous membrane, presence of lumps or threads of viscous sputum in the lumen of the bronchi and bronchospasm (with bronchitis, bronchial asthma ); usually heard on exhalation (rarely in the inspiratory phase). Dry rales have a musical timbre, can be humming, buzzing (in the presence of viscous sputum in the large and medium bronchi), wheezing (with bronchospasm, narrowing of the small bronchi). The abundance and nature of dry wheezing changes significantly after coughing. In bronchial asthma, dry rales are often heard from a distance, have a rich timbre color (“harmonium plays”). Listening to dry wheezing in dynamics is used not only in diagnostics, but also to assess the effect of bronchodilators and expectorants.