The HSE pneumotachometer PTM is a transducer for airflow measurement on rodents. The main feature of the new design is the small dead space. This ensures a good gas exchange in acute experiments. In combination with the silicon rubber tubing and the tracheal cannula the PTM is used for acute experiments (Intubation or tracheotomy). It is also designed for respiratory flow measurement on isolated lung of rats, guinea pigs or mice.
These pneumotachs are made of transparent perspex, which allows good viewing of the inside during the experiment. It also makes these units easier to clean. The flow resistance consists only of straight boring and also is easy to clean.
The transparent design allows easy detection of any mucus that comes up into the PTM during the experiment. This prevents measurement errors caused by artificial increases of the airway resistance due to pneumotach obstruction. In addition the perspex has low heat transfer properties compared to metal so that heating is not needed to prevent condensation of the moisture in the expired air.
The basic principle of the transducer is the generation of a pressure proportional to the airflow across a flow resistance. For the measurement of the pressure we recommend the Validyne differential pressure transducer type DP 45-14.
Calibration:
The PTM type 378/X are only calibrated approximately. The values in the technical specifications are only nominal values and are subject to change in the range of manufacturing tolerance. Volume calibration (injection of a specific volume using a calibrated syringe and integration of the flow signal) must be performed for each experiment.