You searched for: “body plethysmograph
body plethysmograph (s), body plethysmographs (pl) (nouns)
A body area that is used to measure lung volume and pressure.

This body plethysmograph device is used for studying alveolar pressures, lung volumes, and airway resistance. The patient sits or reclines in an airtight compartment and breathes normally.

The pressure of the body plethysmograph changes in the alveoli (tiny sac for holding air in the lungs) when it is alternated by the direction of motions in the compartment and are recorded automatically.