Integration of catheter flow sensor onto tracheal intubation tube system

A MEMS flow sensor was integrated into the tracheal intubation tube system to avoid the misguided insertion of the tube into the esophagus. MEMS technology was used to fabricate a thermal flow sensor onto a flexible polyimide film, and then a heat shrinkable tube was used as packaging to mount it on the inside surface of the tube to produce a catheter flow sensor configuration. The catheter flow sensor was integrated into the inside of the slip joint by using an adapter produced using a molding process. The relationship between the sensor output and the flow rate was evaluated, and closely-matched sensor outputs for both the forward and backward flows were obtained. The tracheal tube in the developed system was inserted into the air passage of a rabbit, and the air flow passing through the tube was directly measured by the integrated catheter flow sensor in real-time. We believe that a doctor can easily evaluate whether the tube is inserted into the bronchi or the esophagus when using our system.