Lung Sounds can indicate to clinicians what is occurring in the lungs. They assist in diagnosis and treatment.
There are two types of lung sounds auscultated (heard): Normal and Abnormal (Adventitious).
There are 8 types of lung/breath sounds:
Vesicular breath sounds are low pitched and soft with a rustling quality during inspiration and are softer during expiration. These are the most common lung sounds, generally heard over the most of the lung surface. They have an inspiration/expiratory ratio of 3 to 1 or I:E ratio of 3:1.
2. Crackles-Fine (Rales)
Fine crackles are popping, quick, discontinuous breath sounds that are high-pitched. Fine crackles are also related to the sound of wood burning in a fireplace, or Velcro being pulled apart or cellophane being crumpled in your hand.
Crackles, formerly termed rales, can be auscultated in both phases of breathing. Early inspiratory and expiratory crackles are the hallmark indication of chronic bronchitis. Late inspiratory crackles may mean CHF (Congestive Heart Failure), pneumonia or atelectasis.
3. Crackles-Coarse (Rales)
Coarse crackles are discontinuous, brief, popping lung sounds. Compared to fine crackles they are louder, lower in pitch and last longer. They make a clear bubbling sound. You can simulate this sound by rolling strands of hair between your fingers near your ear.
Wheezes are adventitious/abnormal lung sounds that are continuous with a musical quality. Wheezes can be low or high pitched. Lower pitched wheezes have a moaning or snoring quality. High pitched wheezes may have an auscultation sound similar to squeaks.
The degree of airway obstruction generally corresponds to the proportion of the respiratory cycle occupied by the wheeze.
Wheezes are caused by narrowing of the airways.
5. Rhonchi-Low Pitched Wheezes
Low pitched wheezes (rhonchi) are continuous, heard on both inspiratory and expiratory phases and are low pitched adventitious/abnormal lung sounds that are similar to wheezes. They often have a rattle-like, gurgling quality.
Rhonchi occur in the bronchi, larger airways. Rhonchi are heard in the chest wall where bronchi occur, not over any alveoli. Rhonchi typically clear after coughing.
Bronchial breath sounds are hollow, tubular sounds that are lower pitched. They can be auscultated over the trachea where they are considered normal.
There is a distinct pause in the sound between inspiration and expiration. I:E ratio is 1:3 .
7. Pleural Rubs
Pleural rubs are continuous or non-continuous, grating or creaking sounds. The sound has been described as similar to a leather-on-leather type or the sound of walking on fresh snow. Coughing will not change the sound. They are caused by two inflamed surfaces sliding by one another, such as in pleurisy.
During auscultation, pleural rubs can usually be localized to a particular place on the chest wall..
Because these sounds occur whenever the patient’s chest wall moves, they appear on inspiration and expiration. Pleural rubs stop when the patient holds her breath. If the rubbing sound continues while the patient holds a breath, it may be a pericardial friction rub.
I:E ratios are equal. These are normal lung sounds in the mid-chest or in the posterior chest between the shoulder blades. They exhibit a mix of the pitch of the bronchial lung sounds heard over the trachea and the alveoli as with the vesicular sound. They have an I:E ratio of 1:1.
With time and a lot of practice you will become an expert at listening to lung sounds and clinical diagnosis related to those lung sounds. You will become a valuable member of the healthcare team and your expertise will be valued immensely.