초록 ▼

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 p

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.

대표청구항 ▼

In a respiratory ventilator of the type having means for providing a respiratory assist cycle for a patient, a mechanism for controlling said assist cycle providing means, comprising: breathing conduit means adapted for fluid communication with the breathing passages of said patient; a sensing tube

In a respiratory ventilator of the type having means for providing a respiratory assist cycle for a patient, a mechanism for controlling said assist cycle providing means, comprising: breathing conduit means adapted for fluid communication with the breathing passages of said patient; a sensing tube in fluid communication with said breathing conduit means and receptive to patient-induced respiratory pressures therein, said sensing tube having a restricted-diameter passageway therethrough which is subject to said patient-induced respiratory pressures; pressure-sensitive means coupled to said sensing tube and in fluid communication with said passageway, for generating a high velocity, low volume flow of gas through said passageway in a first direction in response to an inhalation-induced pressure sensed through said sensing tube, and in a second direction in response to an exhalation-induced pressure sensed through said sensing tube, the velocity and volume of said flow of gas being determined, at least substantially in part, by the restricted diameter of said passageway; fluid flow sensing means in said passageway for producing a first electrical output signal having a first predetermined output level in response to a flow of gas in said first direction and a second electrical output signal having a second predetermined output level different from said first predetermined output level in response to a flow of gas in said second direction; and control means, responsive to said first and second electrical output signals, for actuating said assist cycle providing means in response to said first electrical output signal, and blocking the actuation of said assist cycle providing means in response to said second electrical output signal.