or when he has nervous trembling, or diseases of the respiratory muscles, etc. Interrupted breathing over a limited part of the lung indicates difficult passage of air from small bronchi to the alveoli in this region and uneven unfolding of the alveoli. Interrupted breathing indicates pathology in fine bronchi and is more frequently heard at the apices of the lungs during their tuberculosis infiltration.
Bronchial breathing/respiration (laryngotracheal respiration)
Respiratory sounds known as bronchial or tubular breathing arise in the larynx and the trachea as air passes through the vocal slit. As air is inhaled, it passes through the vocal slit to enter wider trachea where it is set in vortextype motion. Sound waves thus generated propagate along the air column throughout the entire bronchial tree. Sounds generated by the vibration of these waves are harsh. During expiration, air also passes through the vocal slit to enter a wider space of the larynx where it is set in a vortex motion. But since the vocal slit is narrower during expiration, the respiratory sound becomes louder, harsher and longer. This type of breathing is called laryngotracheal (by the site of its generation).
Bronchial breathing is well heard in physiological cases over the larynx, the trachea, and at points of projection of the tracheal bifurcation (anteriorly, over the manubrium sterni, at the point of its junction with the sternum, and posteriorly in the interscapular space, at the level of the 3rd and 4th thoracic vertebrae). Bronchial breathing is not heard over the other parts of the chest because of large masses of the pulmonary tissue found between the bronchi and the chest wall.
Bronchial breathing can be heard instead of vesicular (or in addition to the vesicular breathing) over the chest in pulmonary pathology. This breathing is called pathological bronchial respiration.
It is conducted to the surface of the chest wall only under certain conditions, the main one being duration of the pulmonary tissue when the alveoli are filled with effusion (acute lobar pneumonia, tuberculosis, etc.), with blood (lung infarction), or due to compression of the alveoli by air or fluids accumulated in the pleural cavity, and compression of the lung against its root (compression atelectasis). In such cases the alveolar walls do not vibrate, while consolidated airless pulmonary tissue becomes a good conductor of sound waves in laryngotracheal respiration to the surface of the chest wall. Lungs may be consolidated due to replacement of the inflated pulmonary tissue by connective tissue (pneumosclerosis, carnification of the lung lobe, which sometimes occurs in acute lobar pneumonia, etc.).
Depending on degree of induration, its size and location in the lung, pathological bronchial breathing may have different intensity and pitch. If induration is large and superficial, loud bronchial breathing is heard as if near the ear. Bronchial breathing can be heard in acute lobar pneumonia at its
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second stadium (affection of the entire lobe of the lung). Especially soft and low sounds are heard inpatients with compression atelectasis.
Pathological bronchial breathing can be heard if an empty cavity is formed in the lung (abscess, cavern) and it is communicated with the bronchus. Consolidation of pulmonary tissue round the focus facilitates conduction of sound waves of laryngotracheal respiration to the surface of the chest wall, the more so that sound is intensified in the resonant cavity at the moment of air passage from narrow bronchus the air is set in vortex motion.
Depending the origin there are three types of pathological bronchial respiration:
1) Infiltrative type arises in consolidation of a pulmonary tissue (II stages of acute lobar pneumonia, infarct of lungs, tuberculosis),
2) Cavitary type is auscultated above superficially posed smooth-bore lumen of the big diameter connected with a bronchus (an abscess, a tubercular cavern, bronchiectasias with an appreciable distention of bronchi), 3) Atelectatic type - it is observed in compression atelectasis (exsudative pleurisy of 1,5-3 litres), is auscultated at a column on high bound of a dullness where is compressiated lung, rarely passes for lin. axillaries
anterior.
Amphoric respiration arises in the presence of a smooth-wall cavity (not less than 5-6 cm in diameter) communicated with a large bronchus. Sounds of this kind can be produced by blowing over the mouth of an empty glass or clay jar. This altered bronchial breathing is there called amphoric (Gk amphoeus jar).
Metallic respiration differs from both bronchial and amphoric. It is loud and high, and resembles the sound produced when a piece of metal is struck. Metallic respiration is heard in open pneumothorax when the air of the pleural cavity communicates with the external air.
Stenotic respiration is exaggerated laryngotracheal breathing which is heard in cases with narrowed trachea or large bronchus (due to a tumour); it is heard mainly ay points where physiological bronchial breathing is normally heard.
Bronchovesicular or mixed respiration is heard in lobular pneumonia or infiltrative tuberculosis, and also in pneumosclerosis, with foci of consolidated tissue being seated deeply in the pulmonary tissue and far from one another. Mixed breathing, when the inspiration phase is characteristic of vesicular breathing and the expiration phase of bronchial breathing, is often heard in such cases instead of weak bronchial breathing.
Adventitious sounds (additional respiratory sounds)
Adventitious sounds are rales, crepitation, and pleural friction.
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Rales arise in pathology of the trachea, bronchi, or if a cavern is formed in the affected lung. Rales are classified as dry (rhonchi) and moist rales.
Dry rales, or rhonchi, may be due to various causes. The main one is constriction of the lumen in the bronchi. Constriction may be total (in bronchial asthma), non-uniform (in bronchitis), or focal (in tuberculosis or tumour of the bronchus). Dry rales can be due to (1) spasms of smooth muscles of the bronchi during attacks of bronchial asthma; (2) swelling of the bronchial mucosa during its inflammation; (3) accumulation of viscous sputum in the bronchi which adheres to the wall of the bronchus and narrows its lumen; (4) formation of fibrous tissue in the walls of separate bronchi and in the pulmonary tissue with subsequent alteration of their architectonics (bronchiectasis, pneumosclerosis); (5) vibration of viscous sputum in the lumen of large and medium size bronchi during inspiration and expiration: being viscous, the sputum can be drawn (by the air stream) into threads which adhere to the opposite walls of the bronchi and vibrate like strings.
Dry rales are heard during inspiration and expiration and vary greatly in their loudness, tone and pitch. According to the quality and pitch of the sounds produced, dry rales are divided into sibilant rales (high-pitched and whistling sounds ,or ronchi sibilantes) and sonorous rales (low-pitched and sonoring sounds, or ronchi sonori). High-pitched rales are produced when the lumen of the small bronchi is narrowed, while low-pitched sonorous rales are generated in stenosis of medium caliber and large caliber bronchi or when viscous sputum is accumulated in their lumen.
Propagation and loudness of dry rales depend on the size of the affected area in the bronchial tree, on the depth of location of the affected bronchi, and the force of the respiratory movements. When the walls of a medium size and large bronchi are affected to a limited extent, rhonchi are insignificant and soft. Diffuse inflammation of the bronchi or bronchospasm arising during attacks of bronchial asthma is attended by both high-pitched sibilant and low-pitched sonorous rales which vary in tone and loudness. These rhonchi can be heard at a distance during expiration. If rhonchi are due to accumulation of viscous sputum in the bronchi, during deep breathing (or immediately after coughing) they can be either intensified or weakened, or else disappear altogether for a short time.
Moist rales are generated because of accumulation of liquid secretion (sputum, edematous fluid, blood) in the bronchi through which air passes. Air bubbles pass through the liquid secretion of the bronchial lumen and collapse to produce the specific cracking sound. This sound can be simulated by bubbling air through water using a fine tube. Moist rales are heard during both the inspiration and expiration, but since the air velocity is higher during inspiration, moist rales will be better heard at this respiratory phase.
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Depending on the caliber of bronchi where rales are generated, they are classified as fine, medium and coarse (large) bubbling rales. Fine bubbling rales are generated in fine bronchi and are percepted by the ear as short multiple sounds. Rales originating in the finest bronchi and bronchioles are similar to crepitation from which they should be differentiated (see below). Medium bubbling rales are produced in bronchi of a medium size and coarse bubbling rales in large caliber bronchi, in large bronchiectases, and in pulmonary cavities (abscess, cavern) containing liquid secretions and communicating with the large bronchus. Large bubbling rales are characterized by a lower and louder sound.
Moist rales originating in superficially located large cavities (5—6 cm and over in diameter) may acquire a metallic character. If segmentary bronchiectases or cavities are formed in the lung, rales can usually be heard over a limited area of the chest. Chronic bronchitis or marked congestion in the lungs associated with failure of the left chambers of the heart is as a rule attended by bilateral moist rales of various calibers, which occur at the symmetrical points of the lungs.
Depending on the character of the pathology in the lungs, moist rales are subdivided into consonating or crackling, and non-consonating or bubbling rales. Consonating moist rales are heard in the presence of liquid secretions in the bronchi surrounded by airless (consolidated) pulmonary tissue or in lung cavities with smooth walls surrounded by consolidated pulmonary tissue. The cavity itself acts as a resonator to intensify moist rales. Moist consonating rales are heard as if just outside the ear. Consonating rales in the lower portions of the lungs suggest inflammation of the pulmonary tissue surrounding the bronchi. Consonating rales heard in the subclavicular or subscapular regions indicate tuberculosis infiltration or cavern in the lung.
Non-consonating rales are heard in inflammation of bronchial mucosa (bronchitis) or acute edema of the lung due to the failure of the left chambers of the heart. The sounds produced by collapsing air bubbles in the bronchi are dampened by the "air cushion" of the lungs as they are conducted to the chest surface.
Crepitation
As distinct from rales, crepitation originates in the alveoli. Some authors erroneously classify these sounds as crepitant and subcrepitant rales. Crepitation is a slight crackling sound that can be imitated by rubbing a lock of hair. The main condition for generation of crepitation is accumulation of a small amount of liquid secretion in the alveoli. During expiration, the alveoli stick together, while during inspiration the alveolar walls are separated with difficulty and only at the end of the inspiratory movement. Crepitation is therefore only heard during the height of inspiration. In other words, crepitation is the sound produced by many alveoli during their simultaneous reinflation.
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Crepitation is mainly heard in inflammation of the pulmonary tissue, e.g. at the first (initial) and third (final) stages of acute lobar pneumonia, when the alveoli contain small amounts of inflammatory exudate, in infiltrative pulmonary tuberculosis, lung infarction, and finally in congestions that develop due to insufficient contractile function of the left-ventricular myocardium or in marked stenosis of the left venous orifice of the heart. Crepitation can be heard in the inferolateral portions of the lungs of aged persons during first deep inspirations, especially so if the patient was in the recumbent position before auscultation. The same temporary crepitation can be heard in compressive atelectasis. During pneumonia, crepitation is heard over longer periods and disappears when a large amount of inflammatory secretion is accumulated in the alveoli or after its complete resolution.
By its acoustic properties, crepitation can often resemble moist fine rales that are produced in fine bronchi or bronchioles filled with liquid secretion. Differentiation of moist rales from crepitation is of great diagnostic importance. Persistent crepitation may indicate pneumonia while fine nonconsonating rales suggest bronchitis.
Differential-diagnostic signs of these rales and crepitation are as follows: moist fine rales are heard during both inspiration and expiration; they can be intensified or disappear after coughing, while crepitation can only be heard at the height of inspiration; it does not change after coughing.
Pleural friction sounds (murmur)
In physiological conditions visceral and parietal layers of the pleura are constantly "lubricated" by pleural fluid and are therefore smooth. Their friction during breathing is noiseless. Various pathological conditions alter the physical properties of the pleural surfaces and their friction against one another becomes more intense to generate a peculiar adventitious noise, known as the pleural friction sound. Fibrin is deposited in inflamed pleura to make its surface rough; moreover, cicatrices, commissures, and bands are formed between pleural layers at the focus of inflammation. Tuberculosis and cancer are also responsible for the friction sounds.
Pleural friction sounds are heard during both inspiration and expiration. The sounds are differentiated by intensity, or loudness, length, and site over which they are heard. During early dry pleurisy the sounds are soft and can be imitated by rubbing silk or fingers in the close vicinity of the ear. The character of pleural friction sound is altered during the active course of dry pleurisy. It can resemble crepitation or fine bubbling rales (sometimes crackling of snow). In pleurisy with effusion, during the period of rapid resorption of exudate, the friction sound becomes coarser due to massive deposits on the pleural surfaces. This friction (to be more exact, vibrations of the chest) can be even identified by palpation of the chest.
The time during which pleural friction sound can be heard varies with diseases. For example, in rheumatic pleurisy pleural friction is only heard
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