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Fast integrated flow plethysmograph for small mammals.

Authors
Type
Published Article
Journal
Journal of applied physiology: respiratory, environmental and exercise physiology
Publication Date
Volume
50
Issue
5
Pages
1104–1110
Identifiers
PMID: 7228761
Source
Medline
License
Unknown

Abstract

The accurate measurement of a forced vital capacity (FVC) maneuver in a small mammal requires that the plethysmograph in use have good response characteristics at high frequencies. We develop, on a theoretical basis, the behavior of zeroth-order (pressure type), first-order (flow type without inertance), and second-order (flow type with inertance) plethysmogrphs. The actual frequency response of a mouse-sized plethysmograph is then presented, and a technique for improving its response characteristics is described. A flat amplitude response (within 3% of a reference flow taken as truth) was obtained for sinusoidal inputs below 240 Hz. A phase lag with respect to the reference flow equivalent to a simple time delay of 1.4 ms was observed up to 150 Hz. A typical FVC curve for a mouse is shown, and criteria are provided for designing similar plethysmographs suitable for use with larger animals.

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