The process in which listening to lung sounds with the help of stethoscope is known as lung auscultation. It is a technique to evaluate the chart assessment and inspection.
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| Lung Auscultation |
Stethoscope
In 1816, Stethoscope was first invented by René-Théophile Hyacinthe Laennec. It is used to listen the sounds from heart, lungs or intestines and help to determine the cause if there is any breathing difficulty such as in case of asthma or pneumonia. It is covenient and safe with no radiations.
Parts of Stethoscope
- Ear pieces
- Eartube
- Tubing
- Headset
- Stem
- Chestpiece
- Diaphragm
- Bell
Precautions during Auscultation
According to essentials of Cardiopulmonary Physical Therapy
- If patient comes with poor balance then prevent patient from falling
- Prevent patient from becoming dizzy
- Maintain appropriate draping of patient, especially in female
- If auscultation sounds are very faint or distant, then recheck the sounds again by reminding the patient to take deep breaths or to breathe in and out through mouth.
With this auscultation process, the abnormal sounds like wheezes, crackles or the areas of consolidation can be easily identified.
Lung Sounds
Firstly, knowing about lung sounds helps to improve observational skills.
Mainly lung sounds divided into 2 types
- Normal (Vesicular)
- Adventitious (Abnormal breath sounds)
Normal (Vesicular)
It occurs when vocal cords vibrate during inhalation and exhalation. These are soft and low pitch sounds which heard primarily during inspiration, prominent at top of lungs and centrally
In normal sound, expiration is shorter and quieter than inspiration
There are also different breath sounds which are normal and auscultated at different points like at tracheobronchial tree.
The bronchial breath sounds (tubular sounds) are loud and high pitched sounds. The third one is bronchovesicular which is normal breath sound heard over the junction of mainstem bronchi with segment bronchi. These bronchovesicular sounds are actually softer version of bronchial sound. It can also be heard posteriorly between two scapulas.
How these normal lung sounds produced?: through turbulence of airflow in airways.
Adventitious (Abnormal breath sounds)
There are 2 types of adventitious sounds:
- Continuous (wheezes) or (rhonchi)
- Discontinuous (crackles) or (rales)
Further Divisions of adventitious breath sounds
Wheeze and Rhonchi
Wheeze is continuous adventitious lung sound, with constant pitch and varying duration. The term rhonchi as low pitch adventitious sound still commend by some researchers. But ATS-ACCP recommends referring to all continuous adventitious sounds as wheezes and specifying whether they
are high pitched or low pitched.
They are most common during expiration, and related to airways obstruction i.e. bronchospasm or when secretions are narrowing the airways.
There are two main causes of wheezing including lung diseases e.g COPD and asthma. Other causes include allergies, bronchitis, emphysema or pneumonia.
During bronchodilator treatment, these wheezes diminished or change in pitch.
Crackles (Rales)
The crackles are discontinuous adventitious sounds. It sounds like brief bursts of popping bubbles and is commonly heard during inspiration. Crackles are associated with obstructive respiratory disorders and may result from sudden opening or closing of airways or due to any movement in secretions during inspiration and expiration. Some researchers or clinicians still use the term rales.
Crackle sounds can be heard in the following conditions:
- Atelectasis
- Pulmonary edema
- Fibrosis
- Compression from Pleural effusion
Pleural Rub
Pleural rub sound auscultated at the level of lower lateral chest areas and occurs with each inspiration and expiration. This sound is an indication of pleural inflammation and it’s like two pieces of leather or sandpaper rubbing together.
Chest X-ray zones
There are four zones
- Apical Zone: above the clavicles
- Upper Zone: below the clavicles
- Mid Zone: level of hilar structures
- Lower Zone: Bases
Positions to Hear Sounds
- Tracheal: Over the trachea (above the sub clavicular notch)
- Bronchial: Over the manubrium
- Bronchovesicular: 1st and 2nd intercostal spaces, next to sternum and between scapula.
Patient’s Position
Patient’s position for auscultation is sitting in a chair or on the side of bed. It is important to consider a patient’s clinical condition and comfort, because some patients can tolerate the position of 45° angle.
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