Wireless Stent Flow Sensor System for the Evaluation of Breathing Airflow in the Airway of Experimental Animals

Abstract

A wireless stent flow sensor system was developed to evaluate the changes in breathing characteristics in the airways of experimental animals caused due to drug administration under free movement conditions for drug development. The system was composed of a stent flow sensor, a signal conditioning module, and a PC module. To develop the stent flow sensor, a tube flow sensor and a stent structure were separately fabricated, and they were interlocked at the connection area formed on both elements. The analog sensor outputs were converted into digital outputs with a sampling frequency of 1.0 kHz in a signal conditioning module and transmitted to a PC module through Bluetooth Low Energy 5.0 operated at 2.4 GHz, as the wireless communication. The stent flow sensor and the signal conditioning module were operated using a 165-mAh battery. A simulation experiment was conducted using a plush doll after obtaining calibration curves. A transparent tube was used as the airway and it was placed inside the doll, and an artificial ventilator designed for a small experimental animal was connected to the tube. The stent flow sensor fixed inside the tube was connected to the airway tube, and the signal conditioning module was placed on the back of the neck of the doll. The stent flow sensor output was successfully transmitted to the PC module through Bluetooth. It was demonstrated that the system developed in this study can measure the breathing airflow with a tidal volume accuracy of less than 3.7%.