Pulmonary auscultation is a clinical technique to explore and evaluate the state of the respiratory system.
This procedure evaluates how the flow of air through the tracheobronchial tree behaves. This test provides information on the state of the lungs and the pleural space.
Pulmonary auscultation is carried out with a stethoscope, an acoustic device, which allows capturing the internal sounds of the body. It is also called a stethoscope. It works as an amplifier of acoustic impulses.
The first step in assessing respiratory conditions and their location is to perform pulmonary auscultation. This is a fundamental tool to specify, complement or initiate the diagnosis of various diseases.
Pulmonary auscultation techniques
To perform pulmonary auscultation, the patient’s collaboration is needed. This varies depending on the age and condition of the same. The most difficult situation occurs with infants because they often cry during the exam.
Each doctor follows a protocol to perform pulmonary auscultation. Usually, you start at the neck, examining the region on both sides.
Then the right and left side are examined, successively, placing the stethoscope on the back and front. All sectors must be covered, including the area under the armpits.
The patient is usually asked to breathe deeply through the mouth. Repeatedly this sucks and expires so that all the noises can be captured very clearly.
The usual thing is that pulmonary auscultation is performed while the patient is sitting in order to compare one lung with the other at the same point. Sometimes you are also asked to speak since the transmission of the voice also provides relevant information.
If the patient can not sit down, pulmonary auscultation should be performed while lying on the side. In this case, it is taken into account that the lung that most ventilates is the one that is in the bottom part.
For its part, the lung above is the one with the most volume of air. Because of this, when lying down, the one that is always listened to is the lung below.
Auscultation of noises in the lungs
During the breath, there are noises that are considered normal. These are those that correspond to a normal transit of air through the tracheobronchial tree. Such normal noises are the following:
- Tracheal noise. It is captured by placing the stethoscope on the neck, in front of the trachea. It is detectable during inspiration and expiration.
- Tracheobronchial noise. To detect it, the stethoscope is located between the first and second intercostal space. It is heard both in front of the thorax and in the interscapular region, in the back. What is examined there are the large bronchi.
- Pulmonary murmur. It is a soft and low-intensity noise, which is produced by the passage of air from the lung to the chest wall. To capture it the stethoscope is located on the back, the front, and the sides, while the patient inspires.
- Normal transmission of the voice. The patient is asked to say a few words and the stethoscope is placed in the trachea. The sound should be clear and strong and should become more tenuous as the stethoscope moves away.
Rather than offering an exact diagnosis, what these auscultations show are relevant data to determine the state of the respiratory system. They also allow establishing if there are signs of any pathology.
Noises that indicate conditions
During pulmonary auscultation, some sounds other than normal sounds may appear. The main abnormal noises are:
- Crackles. Low-intensity noise, similar to that produced when rubbing a lock of hair. Suggests the presence of poorly ventilated areas, inflamed or with fibrosis.
- Wheeze. They are sounds similar to a continuous whistle. They occur when there is obstruction of the airways.
- Roncus. They are a kind of snoring that suggests the presence of secretions in the bronchi.
- Blower breathing. It is also called a tubal murmur. The sound is similar to that produced when blowing through a narrow tube. It suggests the presence of pneumonia.
- Bronchophony or pectoriloquia. The voice is clearly heard, even by lung auscultation in the chest wall. It is also a symptom of pneumonia.
- Pleural rub. A sound similar to the rubbing of two leathers. They are a sign of inflammation in the pleura.
- Pleuritic murmur. Similar to blowing breath, but a little softer. Indicates pleural effusion.
- String or cornet. Similar to the sound that occurs when blowing a horn. It appears when there is obstruction of the larynx or stenosis of a part of the trachea.
- Tracheal rales. A wet sound, typical of conditions in which some secretions cannot be eliminated, in large bronchi and trachea.