Health & Medical Medicine

Clinical Classification of Breath Sounds

Voice sounds are part of auscultation of the lungs.
Normally, voice sounds or vocal resonance is heard, but the syllables are indistinct.
They are elicited in the same manner as vocal fremitus.
Except that the doctor listens with the stethoscope.
Consolidation of the lung tissue produces three types of abnormal voice sounds.
Whispered pectoriloquy, in which the child whispers words and the Nurse hears the syllables.
Bronchophony, in which the child speaks words that are not distinguishable but the vocal resonance is increased in intensity and clarity.
Egophony, in which the child says "ee", which is heard as the nasal sound "ay" through the stethoscope.
Decreased or absent vocal resonance is caused by the same conditions that affect vocal fremitus.
Various pulmonary abnormalities produce adventitious sounds that are not normally heard over the chest.
They are not alterations of normal breath sounds but rather sounds that occur in addition to normal or abnormal breath sounds.
They are often referred to as the three "Rs" rales (from the French word meaning "rattle"), rhonchi, and rubs.
Considerable practice with an experienced Tutor is necessary to differentiate the various types of adventitious sounds.
Often it is best to describe the type of sound heard in the lungs rather than to try and label it correctly.
Rales result from the passage of air through fluid or moisture.
They are more pronounced when the child takes a deep breath.
Even though the sound may seems continuous, it is actually composed of several discrete sounds, each originating from the rupture of a small bubble.
The type of rales is determined by the size of the passageway and the type of exudates the air passes through.
They are roughly divided into three categories; fine, medium, and coarse.
Fine rales (sometimes called crepitant rales) can be simulated by rubbing a few strands of hair between the thumb and index finger close to the ear or by slowly separating the thumb and index finger after they have been moistened with saliva.
The result is a series of fine crackling sounds.
Fine rales are most prominent at the end of inspiration and are not cleared by coughing.
They occur in the smallest passageways, the alveoli and bronchioles.
Medium rales are not as delicate as fine rales and can be simulated by listening to the "fizz" from recently opened carbonated drinks of by rolling a dry cigar between the fingers.
They are prominent earlier during inspiration and occur in the larger passages of the bronchioles and small bronchi.
Coarse rales are relatively loud, coarse, bubbling, gurgling sounds that occur in the large airways of the trachea, bronchi, and smaller bronchi.
Often they clear partially during coughing.
They are frequently heard in dying patients because the cough reflex is depressed, allowing thick secretions to accumulate in the trachea and major bronchi and also because, they are so common when death is imminent.
Coarse rales are often called "the death rattle".
Rhonchi are sounds produced as air passes through narrowed passageways, regardless of the cause, such as exudates, inflammation, spasm, or tumor.
Rhonchi are continuous, since sound is produced as long as air is being forced past an obstruction.
Although they are often more prominent during expiration, they are usually present during both phases of respiration.
Rhonchi are classified according to pitch as sibilant or sonorous.
Sibilant rhonchi are high pitched, musical wheezing or sqeaking in character.
The wheezing quality is often more pronounced on forced expiration.
Sibilant rhonchi are produced in the smaller bronchi and bronchioles.
Sonorous Rhonchi are low pitched and often snoring or moaning in character.
They are produced in the large passages of the trachea and bronchi.
Like coarse rales, they can be partly cleared by coughing.
Some clinicians classify sonorous rhonchi as coarse rales, or vice versa.
The other adventitious sound of importance is the pleural friction rub.
Its sound can be simulated by cupping one hand to the ear and rubbing a finger of the other hand across the cupped hand.
The most common site for a friction rub to be heard is the lower antero- lateral chest wall (between the midaxillary and midcalvicular lines), the areas of the greatest thoracic mobility.
Breath sounds are of immense clinical importance in diagnostic processes.

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