The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 09, 1982
Filed:
Apr. 14, 1980
Raymond A Ellestad, Rialto, CA (US);
Finn Sveen, Redlands, CA (US);
Bear Medical Systems, Inc., , CA (US);
Abstract
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 a low volume flow of air in the sensor tube past the thermistor assembly at a high velocity, so that a very small effort to breathe will draw a limited volume of air past the thermistor assembly at a high velocity, causing rapid cooling. The air will flow past the thermistor assembly in a first direction in response to an inhalation effort, and in a second direction in response to an exhalation effort. A heating element is arranged in the tube so that a first temperature-related voltage change is produced across the thermistor assembly when air flow is in the first direction, and a second such temperature-related voltage change is produced when air flow is in the second direction. The first voltage change resulting across the thermistor assembly is utilized to signal a patient effort to inhale and to command the ventilator to furnish an appropriate response, while the second voltage change, signaling an exhalation effort, is used to block such a response.