Auscultation in Human Physiology

Auscultation is a diagnostic procedure where the physician listens to sounds within the body to detect certain conditions or defects, such as pregnancy or heart valve malfunctions. Originally, auscultation was performed by placing the ear directly on the abdomen or chest, but mainly, it has been practised with a stethoscope in 1819, since the invention of that instrument.

This is the simple auscultation definition.

About the Auscultation Technique

This technique is based on the characteristic sounds produced, in the head and anywhere else, by the abnormal blood circuits; in the joints by the roughened surfaces; intestinal disturbances or an active foetus can cause pain in the lower arm, and intestinal disturbances or an active foetus can cause pain in the abdomen. However, it is employed most commonly in diagnosing diseases of the lungs and heart.

The heart sounds mainly consist of two separate noises taking place when the two sets of heart valves close. Either the partial obstruction of these valves or the blood leakage through them because of the imperfect closure results in the turbulence of blood current, causing prolonged, audible noises known as murmurs. In certain congenital abnormalities of the blood vessels and heart in the chest, the murmur can be continuous.

Often, murmurs are particularly diagnostic for the diseases of the individual heart valves; it means they sometimes reveal which heart valve is causing the ailment. Similarly, modification of the heart's sound quality may reveal weakness or disease of the heart muscle. Also, auscultation is useful in determining the irregular rhythm types of the heart and in discovering the sound peculiar to the pericardium inflammation, the sac surrounding the heart.

In addition, auscultation meaning reveals the modification of sounds that are produced in the sacs and air tubes of the lungs during breathing when these particular structures are diseased.

Auscultogram

Auscultation sounds can be depicted using symbols to produce an auscultogram. It can be used in cardiology training.

Mediate and Immediate Auscultation

Mediate auscultation is the auscultation medical term for listening to the body’s internal sounds using an instrument (the mediate), generally a stethoscope. It differs from immediate auscultation, which involves pressing the ear against the body.

Doppler Auscultation

In the 2000s, it was demonstrated that Doppler auscultation using the hand-held ultrasound transducer enables the auscultation of blood flow and valvular movements sound that are undetected during the cardiac examination using a stethoscope. The Doppler auscultation, which presented a sensitivity of 84 percent for the detection of aortic regurgitations, while the classic stethoscope auscultation presented a sensitivity of 58 percent. Furthermore, Doppler auscultation was superior in the impaired ventricular relaxation detection. Since the physics of Doppler auscultation and the classic auscultation are completely different, it has been suggested that both methods could complement each other.

The figure given below shows a student listening to her own heart using a hand-held doppler, which is one of the auscultation meanings.

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Auscultate Lung Sounds (Normal)

Vesicles are usually quiet during the inspiratory process, with a distinct pause before the louder expiratory phase. They are low-pitched and soft with a rustling quality during the inspiration, and they are even softer during the expiration. These are also the most frequently auscultated breath sounds, which can be heard through the majority of the lung surface. They have an inspiratory or expiratory ratio of 3:1 (or IE 3:1).

Bronchovesicular

These are heard over the 1st and second intercostal spaces, including the interscapular area. The expiratory and inspiratory phases last about the same amount of time. They are a pitch mixture of bronchial breath sounds and vesicular sound found near the alveoli and trachea.

Bronchial

Normally, these are heard over the manubrium. The phase of expiratory is greater than the inspiratory one. The expiratory pitch is high, and its intensity is loud. Tubular and hollow sounds are lower-pitched.

Tracheal

The tracheal sounds are heard over the trachea directly. Here, the inspiratory phases equal the expiratory phases. The sound is louder, and the pitch is very high.

Auscultate Lung Sounds (Abnormal)

Crackles

Crackles (or rales) are caused by excessive fluid (or secretions) in the airways. It is caused either by a transudate or an exudate. Exudate is because of lung infection, for example, pneumonia while transuding like congestive heart failure. A crackle takes place when a small pop of airway opens during the inspiration after collapsing because of loose secretions or the lack of aeration during the expiration (or atelectasis). Crackles are more common in inspiratory compared to in expiratory.

Crackles are discontinuous and high-pitched. They sound like the hair being rubbed together. There are three different types of crackles, which are fine, medium, and coarse.

• Coarse is usually early inspiratory, and typically, fine are late inspiratory.

• Medium crackles are soft, high-pitched, and very brief. It sounds like rolling a strand of hair between the two fingers. Fine crackles could suggest the interstitial process; for example, congestive heart failure, pulmonary fibrosis.

• Coarse crackles are more low-pitched, longer-lasting, and louder. They also indicate an excessive fluid on the lungs that could be caused by pulmonary oedema from chronic heart disease, aspiration, chronic bronchitis, and pneumonia.