Body plethysmography is a very meaningful study of lung function. Read when to do the exam and how it works!


The Bodyplethysmografie, also called whole body plethysmography, is a test procedure to check lung function. In contrast to spirometry, it is largely independent of the cooperation of the patient, which is why it is well suited for children, for example. Read here how body plethysmography works and which lung function values ​​the doctor can measure.

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  • How does body plethysmography work?

  • Bodyplethysmography: evaluation

How does body plethysmography work?

In body plethysmography, the patient sits in a closed, airtight cabin, about the size of a telephone booth. He breathes through a mouthpiece into a measuring apparatus outside the booth. Breathing movements change the pressure in the lungs. Among other things, this can be used to calculate the pressure in the alveoli (alveolar pressure).

A computer can calculate additional values ​​from the various measured parameters and display them in a diagram. An important advantage of whole body plethysmography over spirometry is that it provides reliable results even in less able-to-co-operate patients. Because the measurement results are not dependent on the air flow in the measuring apparatus. In addition, body plethysmography can also be used to calculate those lung volumes that the patient does not actively use during breathing, for example residual air remaining after exhaling in the airways (functional residual capacity).

Determination of oxygen diffusion capacity

In addition, the doctor can often determine the so-called diffusion capacity of the lung via the apparatuses of a body plethysmography. This is the ability of the lungs to absorb or release oxygen. The patient receives a specially composed test air containing a small amount of carbon monoxide (CO). The patient inhales the CO via the test air and it enters the blood via the lungs. There it binds, similar to oxygen, to the red blood pigment hemoglobin.

From the amount of CO remaining in the exhaled air, it is now possible to easily calculate the amount of carbon monoxide absorbed. Diseases in which the gas exchange capacity of the lung is reduced, for example, pulmonary fibrosis or anemia (anemia).

Bodyplethysmography: evaluation

Following the body plethysmography, the doctor evaluates the results using the diagram created. Of course, the patient no longer has to stay in the measuring cabin. The diagrams are often referred to as breathing loops because of their shape. Some diseases, such as COPD, already show quite characteristic forms of the breathing loop that the doctor explains to the patient. Depending on what the diagnosis is, the doctor discusses after Bodyplethysmografie In addition, the possible therapeutic options and the importance of the disease for the patient.

For these diseases, the examination is important

  • asthma
  • COPD
  • House dust allergy
  • emphysema
  • pleurisy

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