Chapter 4:	Examination of the Chest
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Auscultation

The next step in evaluating the patient’s chest auscultation, the process of listening for bodily sounds. Chest auscultation involves the use of a stethoscope to enhance transmission, and it takes place over the thorax to identify normal or abnormal lung sounds.

The patient, who is being examined sitting upright in a relaxed position, is instructed to breathe a bit more deeply than usual through an open mouth. Their inhalation should be active, and exhalation passive. The RCP should proceed with the auscultation in a systematic manner, examining all lobes on the anterior, lateral, and posterior chest. Beginning at the base, the RCP should compare sides, and work toward the lung apexes. At least one full ventilatory cycle should be evaluated at each stethoscope position.

Correct techniques for performing chest auscultation include:

• Placing the stethoscope’s bell or diaphragm directly against the chest wall

• Keeping the stethoscope’s tubing free from contact with any objects during auscultation

• Turning off any radio or television in the room

• If patient’s chest hair is thick, wet it prior to auscultation

• Ask alert patients to sit up; roll comatose patients on side to auscultate posterior lobes

The most common errors to be avoided during chest auscultation include:

• Listening to breath sounds through the patient’s bed clothes

• Attempting to auscultate in a noisy room

• Permitting the stethoscope’s tubing to rub against bed rails or patient’s clothing

• Misinterpreting chest hair sounds as adventitious lung sounds

• Auscultating only the areas that are convenient to get to

Numerous types of breath sounds can be heard when ausculating over the lungs. Normal breath sounds are generated mainly by the turbulent of air in the larger airways. The turbulent flow creates audible vibrations, producing sounds that are transmitted through the lung and chest wall. Normal lung tissue acts as a filter that primarily passes muffled low-frequency sounds. Normal breath sounds are "breezy" in quality, heard mainly on inspiration, and somewhat faint.

Bronchial breath sounds are considered to abnormal sounds when they are heard over peripheral lung regions. When lung tissue becomes consolidated and increases in density, as it does in pneumonia or atelectasis, the filtering effect is lost. Diminished sounds occur when the intensity of the sound at the site of the larger airways is reduced, or when sound transmission through the lung or chest wall is decreased. The intensity of the sound is reduced with shallow or slow breathing patterns. Chronic airflow obstruction markedly reduces sound intensity throughout all lung fields. Shallow breathing patterns also contribute to decreased breath sounds in COPD patients.

Some of the abnormal breath sounds that may be heard by the RCP during chest auscultation include:

• Wheezes and rhonchi--Wheezes and some rhonchi are vibrations caused by air flowing rapidly through a narrowed airway. Bronchospasm, mucosal edema, or foreign objectives can constrict the airway’s diameter. The pitch of the wheeze is related to the extent of airway narrowing. The greater the narrowing, the higher the pitch. Low-pitched, continuous rhonchi are frequently associated with the excessive presence of secretions in the airways. Some findings regarding the significance of expiratory wheezing include:

patients with chronic airway obstruction who wheeze are more likely to show improvement after bronchodilator administration than those who don’t wheeze;

less intensive wheezing is associated with a wide range of obstructive defects, while more intensive wheezing indicates moderate to severe airway obstruction;

polyphonic wheezing (multiple notes) suggests many obstructed airways, such as with asthma.

• Crackles (rales)--Crackles are discontinuous, bubbling or popping sounds produced when airways pop open as air travels through fluid or small airways. Crackles can also be heard in patients without excess secretions. These occur when collapsed airways pop open during inspiration. While inspiratory crackles are considered abnormal, they can occur in normal individuals in certain situations. Crackles produced by the sudden opening of peripheral airways are called late-inspiratory crackles, and are most common in patients with respiratory diseases that reduce lung volume, including pneumonia, pulmonary edema, fibrosis, and atelectasis.

• Voice sounds--Vocal resonance should be assessed if chest inspection, palpation, percussion, or auscultation suggests any abnormalities. The patient is instructed to repeat the numbers "1, 2, 3" or "99" while the RCP uses a stethoscope to listen over the sides of the chest wall. The three types of vocal sounds heard are:

• Bronchophony--an increase in intensity and clarity of vocal resonance; is indicative of increased lung tissue density.

• Epophony--increased intensity of voice, with a nasal or bleating character; indicative of a compressed lung above a pleural effusion.

• Whispering pectoriloquy--high-frequency vibrations created when patients are asked to whisper "1, 2, 3) while the RCP listens over the lung periphery with a stethoscope; helpful in finding small or patchy areas of lung consolidation.

• Pleural friction rub--creaking or grating sound occurring when pleural surfaces are inflamed, and the roughened edges rub together during breathing; found in patients with pleurisy.