Pneumotachographs (Pneumotachs)

Pneumotachs are used in conjunction with flow transducers to measure respiratory flow rates. Pneumotachs provide a resistance to flow. Flow through this resistance generates a differential pressure upstream versus downstream. This differential pressure is measured with a transducer. Pneumotachs are designed so the relationship between flow and differential pressure is linear across the desired flow range.

Screen Pneumotachs

Buxco incorporates screen pneumotachs in the design of our plethysmographs. Depending on the chamber design and version, each pneumotach may contain one to several screens. When replacing screens that have become fouled, always replace the same number of screens as have been removed. Buxco sells replacement pneumotach screens. We also sell maintenance kits that contain screens appropriate for your chambers.

As suggested, pneumotach screens can become fouled over time by fur, food dust, aerosol deposits, and other debris. Screen fouling can be minimized by making sure that fresh air enters through the pneumotach.

Halcyon™ Pneumotachs

Buxco's patented Halcyon pneumotachs greatly improve signal-to-noise ratios by quieting flow baselines. This can be especially important in noisy environments where foot traffic or ventilation is heavy and where door slams are frequent. Quiet baselines lead to easier calibrations, higher breath acceptance, improved monitoring when pulmonary function is compromised, and, ultimately, more reliable data. Halcyon pneumotachs also provide protection from dust, stabilizing chamber sensitivity.

Halcyon pneumotachs are being designed into most plethysmograph options.

In-line Pneumotachs

When studying larger animals, it may be impractical to use a plethysmograph chamber. In these and other situations it may be desirable to use an in-line pneumotach such as a Fleisch pneumotach. These pneumotachs work by the same principle but are placed directly in the inspiratory and/or expiratory line. Fleisch pneumotachs can be provided in a variety of sizes (flow ranges) covering mice to horses, with or without a thermistor to minimize breath condensation.

When appropriate, Buxco will include in-line pneumotachs in your proposal.