LUNG-CHEST AUSCULTATION- CLINICAL GUIDE
Auscultation is an art of medicine, and requires practice before mastering it. In today's blog, we are going to discuss about Auscultation of Lungs under the section- Respiratory system examination. With auscultating chest, one simply tries to discover further signs of respiratory diseases which are sometimes diagnostic of a lung disease. But what is the auscultation placement for stethoscope and what are we actually going to hear, that is the major scenario here.
|Auscultation of Lungs under Respiratory examination|
Under this page, we will uncover Placement of stethoscope for auscultation of lungs, including anterior lobe, middle lobe and posterior lobe; normal breath sounds including bronchial, vesicular and bronchovesicular sounds; adventitious sounds like rales, crepitations, wheeze, stridor, crackles, etc., and reveal some important tests like whispering pectoriloquy, egophony and bronchophony.
Let's start this wide topic from here:
LOCATIONS FOR AUSCULTATION - STETHOSCOPE PLACEMENT
We have two lungs, which we divide in 3 zones, making it 6 places to auscultate in front and 6 points to auscultate at back. Following are the zones for lung auscultations :-
Each zone corresponds with a lobe of lung. Right lung has 3 lobes- Anterior, middle and posterior; while the left lung has 2 lobes- Anterior and posterior plus lingula that relates with almost middle lobe. These zones are auscultated for abnormalities and therefore, we can pin-point the pathology to specific lobe(s).
|LOCATIONS FOR AUSCULTATION - STETHOSCOPE PLACEMENT|
|Lobes FOR AUSCULTATION - STETHOSCOPE PLACEMENT|
NORMAL BREATH SOUNDS
Normal breath sounds include:
1. Bronchial sound
2. Vesicular sound
3. Bronchovesicular sound
You can also read our post on NORMAL BREATH SOUNDS.
ADVENTITIOUS BREATH SOUNDS
The Adventitious breath sounds or abnormal sounds that are heard during auscultation are clues to greater diagnosis. Following adventitious sounds are often heard in lung auscultation :-
1. Crepitations- Also known as Crackles or Rales, these are high-pitched sounds like crackles in a fireplace.
2. Wheezes- Whistling sounds with musical tone, can be low or high pitched.
3. Rhonchi- These are low-pitched wheezes heard both in inspiration and expiration, and rattle-like or snoring.
4. Stridor- High pitched sounds heard during inspiration, often doesn't require stethoscope.
5. Pleural rub- These are heard as hair rubbing or walking on snow, heard during both inspiration and expiration.
Read our post on Adventitious sounds on lung auscultation (coming soon).
There are some other tests which are performed while auscultation of lungs and these tests are performed as follows and have a reasonable significance :-
1. Bronchophony- It is also known as bronchiloquy.
Technique- Ask the patient to repeat a word, like "ninety-nine" while auscultating the zones of chest and back simultaneously. This produces vibrations which are heard through stethoscope. Observe the vocal resonance of the patient.
Interpretation- Normally, the patients sound is gentle,indistinct and hard to understand on stethoscope during auscultation. But if there is positive bronchophony, there is loudness of voice over the affected lobe. Causes of bronchophony- Consolidation (eg.pneumonia), fibrosis, interstitial lung disease, lung cancer.
2. Egophony- Or Aegophony
Technique- Ask the patient to say "E" in a prolonged fashion like "eeeeee" while auscultating the zones of chest and back simultaneously. Focus on the stethoscope for the sound made.
Interpretation- In normal lungs, it is heard as E only due to clear transmission of sound through clear lungs. However, positive egophony occurs when the word "E" is heard as "A" like "aaaaaa". This transition of E to A is due to dampening effect of sound transmission that occurs due to Consolidation, Pleural effusion or Fibrosis of lung lobe(s).
3. Whispered pectoriloquy- or Whispering pectoriloquy
Technique- Ask the patient to whisper a word, like "ninety-nine" while auscultating the zones of chest and back simultaneously. Observe the vocal resonance of the patient.
Interpretation- Normally, whispered words are very hard to understand on stethoscopes. However, clearly heard words indicate Positive Whispered pectoriloquy. It occurs due to lung cancer or lung consolidation.
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