Abstract: Techniques described herein can identify usage information for sensors. In one example, an anesthesia device can include a processor to obtain usage information from a first flow sensor coupled to the anesthesia device. The processor can also determine the usage information exceeds a predetermined limit and generate an alert indicating the first flow sensor is to be replaced.

Abstract: The thermal time of flight signal guard overcomes the leakage crosstalk problem encountered in prior art systems by eliminating the leakage currents in the flow transducer before they reach the temperature sensors. This is accomplished by the installation of a conductive strip into the fluid flow path, interposed between the temperature sensors and the heat source. The conductive strip intercepts any errant leakage currents that are generated by the heat source and carried by moisture which accumulates on the walls of the fluid flow path to the temperature sensor. The signals that pass through the fluid flow conduit past the conductive strip to the temperature sensors are the thermal tracer signals. Therefore, the temperature sensors operate in a leakage current free environment and the signals produced by the temperature sensors are devoid of leakage current noise.