1.8: Physical Assessment of the Respiratory Tract III: Percussion

The respiratory system, fundamental to life, consists of complex structures responsible for gas exchange. The percussion assessment is critical to understanding this system's health and functionality. This non-invasive assessment technique allows healthcare providers to evaluate the density or aeration of the lungs, thereby identifying potential abnormalities.

Percussion in Respiratory Assessment

Percussion evaluates underlying tissue composition with audible and tactile vibrations, distinguishing among air, fluid, and solid material. Performed on both the anterior and posterior thorax, it can detect changes in the resonance produced by healthy lung tissue. Dullness over the lung may indicate the replacement of air-filled lung tissue by fluid or solid tissue.

The procedure begins with the posterior thorax, across the top of each shoulder, locating the resonance overlying the lung apices. The process continues down the posterior thorax, percussing symmetric areas at 5 to 6 cm intervals. Bony structures such as scapulae or ribs are avoided during this process.

When percussing the anterior chest, begin in the supraclavicular area and progress downwards, one intercostal space at a time. Dullness noted to the left of the sternum between the third and fifth intercostal spaces is usual, as this is the location of the heart. Similarly, a normal span of liver dullness below the lung at the right costal margin is expected.

Diaphragmatic Excursion

An essential part of assessing percussion is evaluating diaphragmatic excursion, which changes position during inspiration and expiration. The diaphragm's range of motion can provide vital clues about lung health.

To evaluate the position and movement of the diaphragm, the patient is asked to take a deep breath and hold it while the maximum descent of the diaphragm is percussed. The distance between the areas of maximum descent during inhalation and exhalation indicates the extent of diaphragmatic motion.

Percussion Sounds

The percussion sounds vary based on the type and condition of the tissue being examined. Here are the typical sounds one might encounter:

• Resonance: A low-pitched sound heard over normal lungs.

• Hyperresonance: A loud, lower-pitched sound than normal resonance heard over hyperinflated lungs, such as in chronic obstructive pulmonary disease and acute asthma.

• Tympany: A drum-like, loud, empty-quality sound heard over a gas-filled stomach, intestine, or pneumothorax.

• Dull: A medium-intensity pitch and duration sound heard over areas of mixed solid and lung tissue, such as the top area of the liver, partially consolidated lung tissue (pneumonia), or fluid-filled pleural space.

• Flat: A soft, high-pitched sound of short duration is heard over very dense tissue where the air is not present, such as the posterior chest below the level of the diaphragm.

In conclusion, percussion is a valuable assessment tool for understanding the anatomy and functionality of the respiratory system. It provides vital insights into lung health and potential abnormalities within the system.

Begin the percussion assessment by positioning the patient upright and leaning forward with arms folded for the posterior chest examination.

Start percussing across the shoulder. Identify a zone of resonance about 5 centimeters above the lung apices.

Then, move downward, percussing symmetric areas every 5 to 6 centimeters, avoiding bony structures.

Next, shift to the anterior chest, initiating percussion in the supraclavicular area, then progressing downward intercostally.

To observe diaphragmatic excursion, ask the patient to inhale deeply. Percuss and mark the transition from resonance to dullness at maximum diaphragm descent.

Next, ask the patient to exhale fully and percuss again to find the dullness level, and measure the distance between the two marks to determine diaphragmatic motion.

Finally, interpret the percussion sounds heard.

Resonance : a low-pitched sound over normal lung tissue.

Hyperresonance : a loud, lower-pitched sound over hyperinflated lungs.

Tympany : a drum-like, loud, hollow sound over a gas-filled pneumothorax.

Dull : a medium-pitched sound over lung tissue.

Flat sound : a soft, high-pitched sound over the diaphragm.