CDC researchers have developed a novel acoustic whole body plethysmograph (AWBP) that allows measurement of tidal volume in lab animals, independent of gas compression in the lung. This system provides particular advantages over the traditional whole body plethysmograph (WBP) when measuring model animals with increased gas compression due to increased airway resistance or increased acceleration in the breathing pattern.

Measurement of tidal volume in conscious, unrestrained mice has traditionally been performed using WBP. An animal is placed in a chamber where pressure changes due to respiration are observed, which are then related to tidal volume. Although the effects of gas compression on the WBP signal of normal mice may be negligible, gas compression in mice with altered breathing pattern and/or increased airway resistance can produce significant errors in the measurement of tidal volume. A major advantage of this novel AWBP technology is the ability to measure the tidal volume signal independent of gas compression. This is particularly useful when measuring mice that have been exposed to a respiratory irritant or toxin that increases airway resistance or the frequency content of the breathing pattern. Further, with slight hardware and software modifications the system may also be used to measure specific airway resistances.