A directional sensor for the detection of a very feeble effort to breathe on the part of a patient whose breathing needs are under the influence and control of a mechanical ventilator. A self-heated thermistor assembly is mounted in a small diameter sensor tube. A diaphragm and chamber arrangement provides...http://www.google.es/patents/US4357936?utm_source=gb-gplus-sharePatente US4357936 - Directional thermistor assist sensing
