Simultaneous Airflow and Pressure Measurements Based on Pitot Tube for Evaluation of Expired Air Inside Lung Airway

In this study, we propose a novel sensor probe system consisting of a basket forceps and two pressure sensors to simultaneously measure the expiratory airflow and the static pressure inside the pulmonary airway. A Pitot tube mechanism using two pressure sensors is introduced in the system for measuring both the physical quantities. Small fiber-optic pressure sensors with 0.3 mm diameter were utilized, and both the airflow rate and the static pressure characteristics were evaluated for obtaining the calibration curves. Finally, the proposed sensor system was implemented to measure both the airflow and pressure in an artificial ventilator and an experimental animal. The measurement of expired airflow and static pressure inside the airway of a rat with the diameter of 1.8 mm were demonstrated.