3. Before using the stethoscope the student should listen carefully to patient's breathing.
Audible breathing at rest can be an important early sign of airways disease.
It may be caused by vibrations of airways tissues or secretions, or by turbulent flow due
to either to increased velocity of flow or to airways narrowing.
A variety of breathing sounds of diagnostic relevance can be detected by unaided
ear.They are
4. 1.Stertorous breathing:
This is due to vibrations of the soft tissues of the nasopharynx, larynx and
cheeks resulting from loss of muscle tone.
It may occur in coma from any cause and in some subjects during sleep(snoring)
2.Rattling breathing:
Due to vibration of mucus retained in the main airways.
This indicates ineffectual cough due to suppression of the cough reflex or
to general weakness.
3.Gasping,grunting and sighing:
These sounds are mainly due to increased velocity of
airflow and can be normal responses to a variety of physical and
emotional stimuli:exercise, pain, cold, fear, grief.When persistent,
however they mayreflect some form of chronic anxiety state.
5. 4.Hissing (Kussmaul's) breathing
is produced by the patient taking deep breaths through a nearly closed
This probably signifies hyperventilation without dyspnoea and therefore
reflex opening of the mouth during inspiration.
It is a sign of severe acidosis, as in diabetic ketosis, uraemia and salicylate
poisoning.
5.Wheezing:
Is usually louder on expiration than on inspiration and denotes narrowing of
bronchi as in asthma.
6. 6.Stridor:
is of lower pitch than wheeze and more closely resembles of a voice sound.It can
be stimulated by partial closure of the vocal chords while breathing deeply.
Unlike wheeze, stridor is at least as loud in inspiration as in expiration for two
reasons a)because it usually results from narrowing of the extrathoracic
airways(trachea or larynx) which are not subject to intrathoracic pressure
changes.b)because the narrowing is often due to rigid lesion such as tumour,
which prevents fluctuation in airways diameter during the respiratory cycle.
7. Auscultation must be carried out
with definite objectives in mind:
To determine whether the breath sounds are equal on the two sides.
To ascertain the character of the breath sounds.
To detect any added sounds and decide their nature, and whether they
are intra or extrapulmonary.
To compare the voice sounds over different parts of the lungs.
8. Auscultation is done all over the lungs front ,axillary regions and back- and sounds at
corresponding points on the two sides are compared.
Since breath sounds during quite breathing are insufficient for study the patient is asked to
breath deeply through open mouth.
The following points are noted
A)The type or character of breath sounds-whether vesicular or bronchial.
B)Intensity of breath sounds-whether diminished or absent.
C)Added or adventitious sounds-crepitation, rhonchi, pleural rub, etc.
D)Character of resonance.
9. Vesicular breath sounds
The vesicular breath sounds are produced by passage of air in the medium and large
bronchi;they get filtered and attenuated while passing through millions of air filled alveoli
before reaching the chest wall.
These sounds are heard during inspiration and expiration.
The inspiratory sound is low pitched and rustling in character, and is always longer than the
expiratory sound.
The expiratory sound which is softer and shorter, follows without a pause and is heard
during early part of expiration.
Normally, breathing over most areas of the chest is vesicular and most typically so in the
axillary and infrascapular regions.
10. Bronchial breath sounds
Bronchial breath sounds originate probably in the same medium and large bronchi, and
replace vesicular sounds when the lung tissue between them and the chest wall becomes
airless as a result of consolidation (as in pneumonia), tuberculosois, carcinoma and
fibrosis.
The bronchial breath sounds are loud, clear, hollow or blowing in character and of high frequencies.
The inspiratory sound becomes inaudible just before the end of inspiration while the expiratory
sound is heard throughout expiration.
Thus the bronchial breath sounds are loud and clear, the inspiratory and expiratory sounds being of
about same duration, and separated by a distinct pause.
11. Bronchial breath sounds can normally be heard over the following areas:
A)Trachea and larynx: The sounds are harsher and llouder than those heard over
diseased lungs.
B)Interscapular region and the apex of right lung: There is more of bronchial element
than vesicular in these regions because the trachea and bronchi come near to the
surface.
C)Bronchial breathing may also be heard in the interscapular, right infrascapular,and
over the lower cervical vertebrae.
12. Added sounds
Chest diseases can give rise to three kinds of added sounds:wheezes, crackles and
pleural friction.
Wheezes are due to the oscillation of airways and other tissues set into motion by
an impediment to airflow.
Fixed monophonic wheeze:
This is a single note of constant pitch, timing and site. It results from air passing at
high velocity through a localized narrowing of one airway.
Bronchial carcinoma is the commonest cause. Stridor is a special example of this
kind.
Random monophonic wheezes:
These are random single notes which may be scattered and overlapping throught
inspiration and expiration and are of varying duration, timming and pitch.
They signify widespread airflow obstruction, as in asthma or bronchitis.
13. Expiratory polyphonic wheeze:
This is a complex musical sound with all its component parts starting together and
continuing to the end of expiration.
It is probably due to expiratory dynamic compression of large central airways and is
audible at the mouth.
When unaccompanied by inspiratory wheezes it usually indicates emphysema in which
the central airways are narrowed by the positive pressure which has to be exerted to empty
the inelastic lungs.
Sequential inspiratory wheezes(squaks)
A series of sequential inspiratory sounds or sometimes a single sound, due to the opening
airways which had become abnormally apposed during the previous expiration
These tend to occur in deflated areas of lung and are therfore heard in various forms of
pumlonary fibrosis, especially fibrosing alveolitis.
14. Crackles:
Crackles result from the explosive equalization of gas pressure between two
airway compartments when a closed section between them suddenly opens.
Early inspiratory and expiratory crackles signify abnormal expiratory closure of
proximal intrapulmonary airways with re-opening later in expiration or early in
inspiration.
They tend to be scanty, low-pitched, audible at the mouth and unaffected by
posture.
They are usually indicative of bronchitis.
Late inspiratory crackles are generally due to restrictive conditions of the lung
resulting in expiratory closure of the small peripheral airways with re-opening at
the end of inspiration.
They are usually fine, profuse, high-pitched, in-audible at ht emouth and
with posture.
They are heard especially in patients with fibrosing alveolitis.pneumonia and
oulmonary oedema.
15. Pleural friction
Oscillations arising from frictional resistance between two layers of
inflamed or roughened pleura produce a creaking
sound:the pleural friction rub.
This tends to recur in the same part or parts of each respiratory
