Auscultation of the lungs

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The respiratory sounds used for diagnosis of diseases of the lungs and is part of the physical examination . In medicine, auscultation means listening to organs with a stethoscope . As part of the auscultation of the lungs, breathing sounds and background noises can be distinguished. The breath sounds can be divided into physiological or normal and pathological or abnormal breath sounds. Noise from the lungs is always pathological.

Physiological breath sounds

Breathing sounds are caused by turbulent air flow. In contrast, the laminar air flow is noiseless. The normal breathing sounds are divided into central and peripheral breathing sounds. The mechanism of creation is the same. They differ in their spectral composition . This is influenced by the transmission distance and the sound-conducting medium.

  • The central breathing sound was formerly also called bronchial breathing or bronchial breathing sound . It is audible through the central airways as a loud, medium to high frequency noise both when inhaling and exhaling .
  • The peripheral respiratory sound was formerly known as vesicular ( vesicles breathing ) or vesicular breath sounds called and created not as previously thought in the alveoli (alveoli). Its origin is also in the central airways, but it is dampened by the lung tissue and is therefore rather quiet and low-frequency. It can be heard at rest, especially during inhalation and at the beginning of exhalation.

Pathological breath sounds

The abnormal breathing sound is caused by either abnormal sound conduction or abnormal sound generation. In the case of abnormal sound generation, the breathing noise is either too quiet, as is found with hypoventilation , or too loud, as occurs with hyperventilation or structural changes in the bronchial tree.

  • Bronchial breath sounds : The sound of breathing is increased when the attenuation is reduced, as is the case with pneumonia or a collapsed lung ( atelectasis ) in the upper lobe of the lung. In healthy people, the breathing noise can only be heard centrally above the windpipe; if it can be auscultated in the periphery, this is considered pathological.
  • Attenuated respiratory sound (engl .: attenuated breath sounds ): Toned is the breathing sound by either enlarged transmission distance, as is the case hyperinflation (eg. Asthma and emphysema ) is the case, or by enhancing the damping factors such. B. in pneumothorax , pleural effusion , pleural rind or lower lobe atelectasis.

Breathing sounds are not to be confused with pulmonary background noises ( see below ).

Pulmonary noise

Pulmonary background noises arise from diseases of the respiratory organs or organs that affect breathing. The classification is based on a historically based designation, which is based on the pathological dissection findings of the sick.

Discontinuous background noise

Discontinuous background noise when inhaling

Discontinuous background noises (formerly damp or non-musical rattle / background noises) can be further subdivided into coarse to fine-bubble rattle noises. Depending on their consistency and localization in the small to large airways, mucus and secretion bubbles trigger noises that are roughly comparable to the sound of the rising and bursting bubbles when opening a lemonade can. Coarse-bubble rattling noises are caused by secretions in the larger airways such as the windpipe and bronchi , while fine- bubble rattling noises are caused by secretions in the smaller airways such as the small bronchi and alveoli .

A special form is the crackling rattle ( sclerosiphony ). It's a sound that can be compared to splashing hot oil in a pan or ripping open a Velcro fastener . It is found in pulmonary fibrosis .

Continuous background noise

Stridor on inhalation and exhalation
Wheezing on inhalation

Continuous background noises (formerly called dry or musical rattling / background noises) are stridor , humming, whistling and wheezing. Constrictions of the airways due to viscous secretions, usually in connection with swelling of the mucous membrane , trigger an accelerated flow that generates audible vibrations of the air column in the airways. They sound more melodic than discontinuous background noises.

  • Humming ( rhonchi ) is a low-frequency noise that is caused by irregular, changing coatings and floating mucus threads in the large airways. If you blow between two sheets of paper that are held together, a humming sound is produced, which stops when the airflow stops.
  • Whistling / wheezing (English wheeze ). Whistling is a high-frequency sound that occurs due to severe constriction of the airways from mucus or contraction of airways. Whistling occurs in everyday life when a gas is emptied with a squeaky sound from a reservoir with a narrow outlet. Wheezing is the orchestral sounding of breathing air, which escapes into the large airways, obstructed by narrowed smallest airways (bronchioles). Whistling and wheezing are often used synonymously . This breathing sound is typical of bronchial asthma and certain forms of chronic obstructive pulmonary disease (COPD). A distinction is made between expiratory wheezing (during exhalation, which occurs with left heart decompensation, bronchial asthma and exacerbated COPD) and inspiratory wheezing during inhalation.
  • Stridor is a flow noise that is audible through the windpipe when you inhale or exhale and that can be carried out through the mouth. A stridor occurs when there is a narrowing of the larynx or trachea.

Web links

literature

  • SURFmed Update 2010, Guidelines Medicine of Switzerland, Philippe Furger.
  • Klaus Holldack, Klaus Gahl: Auscultation and percussion. Inspection and palpation. Thieme, Stuttgart 1955; 10th, revised edition, ibid 1986, ISBN 3-13-352410-0 , pp. 77-98.

Individual evidence

  1. ^ Jörg Braun: Lungs. In: Jörg Braun, Roland Preuss (Ed.): Clinic Guide Intensive Care Medicine. 9th edition. Elsevier, Munich 2016, ISBN 978-3-437-23763-8 , pp. 285-310, here: p. 286.