pressure plethysmograph

pres·sure ple·thys·mo·graph

1. a plethysmograph applied to part of the body, for example, a limb segment, and arranged so that volume is measured during temporary application of sufficient pressure to the part to empty its blood vessels; 2. a body plethysmograph in which changes of body volume are measured in terms of the consequent changes in air pressure in the body plethysmograph.