Abnormal breath sounds include:
The term “adventitious” breath sounds refers to extra or additional sounds that are heard over normal breath sounds. Sources differ as to the classification and nomenclature of these sounds, but most examiners commonly use the following terms to describe adventitious breath sounds.
• crackles (or rales)
• wheezes (or rhonchi)
• pleural friction rubs
Detection of adventitious sounds is an important part of the respiratory examination, often leading to diagnosis of cardiac and pulmonary conditions.
Crackles (or rales) are caused by fluid in the small airways or atelectasis. Crackles are referred to as discontinuous sounds; they are intermittent, nonmusical and brief. Crackles may be heard on inspiration or expiration. The popping sounds produced are created when air is forced through respiratory passages that are narrowed by fluid, mucus, or pus. Crackles are often associated with inflammation or infection of the small bronchi, bronchioles, and alveoli. Crackles that don't clear after a cough may indicate pulmonary edema or fluid in the alveoli due to heart failure or adult respiratory distress syndrome (ARDS).
Wheezes are sounds that are heard continuously during inspiration or expiration, or during both inspiration and expiration. They are caused by air moving through airways narrowed by constriction or swelling of airway or partial airway obstruction.
• Wheezes that are relatively high pitched and have a shrill or squeaking quality may be referred to as sibilant rhonchi. They are often heard continuously through both inspiration and expiration and have a musical quality. These wheezes occur when airways are narrowed, such as may occur during an acute asthmatic attack.
• Wheezes that are lower-pitched sounds with a snoring or moaning quality may be referred to as sonorous rhonchi. Secretions in large airways, such as occurs with bronchitis, may produce these sounds; they may clear somewhat with coughing. Visit EMTprep LungSoundSeries (Wheezes)
Pleural friction rubs are low-pitched, grating, or creaking sounds that occur when inflamed pleural surfaces rub together during respiration. More often heard on inspiration than expiration, the pleural friction rub is easy to confuse with a pericardial friction rub. To determine whether the sound is a pleural friction rub or a pericardial friction rub, ask the patient to hold his breath briefly. If the rubbing sound continues, its a pericardial friction rub because the inflamed pericardial layers continue rubbing together with each heart beat - a pleural rub stops when breathing stops. Visit EMTprep LungSoundSeries Pleural Rub Sounds
Stridor refers to a high-pitched harsh sound heard during inspiration.. Stridor is caused by obstruction of the upper airway, is a sign of respiratory distress and thus requires immediate attention.
If adventitious sounds are heard, it is important to assess:
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