Catheter flow sensor system and breathing measurements in rabbit

A catheter flow sensor system is developed to directly measure the breathing characteristics in small bronchi. The flow sensor is fabricated on a 15-μm thick biocompatible parylene HT film. The film is mounted inside the surface of a thermal shrinkable tube. Finally, a handling tube is connected to one end of the fabricated sensor. A guide tube and a fiberscope are used to insert the sensor into a rabbit bronchus. The fore-end position of the guide tube is confirmed from images taken by the fiberscope. The sensor directly evaluates the breathing characteristics of rabbits having and not having a pneumothorax. The per-cycle flow volume for a rabbit having a pneumothorax is found to be only 70–77% of that for a rabbit not having one.