Microchannel-type Air Detective Sensor using the Change of Dielectric Constant for Medical Applications

Air embolism can be a potentially fatal complication of surgical procedures when air or sub-atmospheric is introduced under pressure into a body cavity. For the diagnosis and the treatment of air embolism quickly and efficiently, we have developed the air detector using microstructure capacitive sensor. The sensor consists of micro-channel on Pyrex 7740 glass with upper and lower electrodes which function as a capacitor. For air sensing, we designed air detection system with air control equipment, capacitance-tofrequency (C-F) signal processing and conversion circuit and LabVIEW monitoring system. In experiments with the system, the proposed system showed a frequency difference depending on the amount of air in the micro-channel of the sensor.