Pressure plethysmograph.
21 C.F.R. § 868.1750
in effectEffective: 2024-07-01(a) Identification. A pressure plethysmograph is a device used to determine a patient's airway resistance and lung volumes by measuring pressure changes while the patient is in an airtight box.
(b) Classification. Class II (performance standards).
Source: eCFRURL: https://www.ecfr.gov/api/versioner/v1/full/2024-07-01/title-21.xmlFetched: 7/26/2026