Implantable catheter flow sensor with legs in air passage for laboratory animal

An implantable catheter flow sensor with legs for measuring the breathing characteristics of disease-model animals was developed. The unique feature of this sensor is the use of legs to fix the sensor to the inside wall surface of the air passage without preventing ciliary motion. Differently shaped legs were fabricated by application of a heat shrinkable tube. Prototype sensors was inserted into tubes with inner diameters ranging from 2.4 to 2.7 mm and successfully anchored to the inside surface by the legs. An evaluation of the relationship between the sensor output and the flow rate demonstrated that the sensor output against the flow rate obeyed King´s law. The sensor output variation with different inner tube diameters was suppressed to less than 3%.