초록 ▼

A detector for determining the volume and volumetric changes of respiratory gases in a closed circuit anaesthesia circuit having a bellows ventilator. The device includes a first sensor positioned with respect to the bellows for detecting and indicating when the bellows assumes a given expanded posi

A detector for determining the volume and volumetric changes of respiratory gases in a closed circuit anaesthesia circuit having a bellows ventilator. The device includes a first sensor positioned with respect to the bellows for detecting and indicating when the bellows assumes a given expanded position in a bellows housing indicative of the given volume of respiratory gas in the circuit. A second sensor detects and indicates when the bellows assumes an expanded position indicative of the greater amount of expansion than that corresponding to the given expanded position. During respiratory cycles of the patient, indications from the first sensor in the absence of indications from the second sensor indicates that the volume of gas in the closed circuit anaesthesia circuit is not changing, but is remaining at that corresponding to the given expanded position of the bellows. Indications from both the first sensor and the second sensor indicates that the degree of expansion of the bellows is greater than that corresponding to the given expanded position and hence the volume of gas in the closed circuit anaesthesia circuit has increased. The absence of indications from both the first and second sensors indicates that the degree of expansion of the bellows is less than that corresponding to the given expanded position and that the volume of gas in the closed circuit anaesthesia circuit has decreased.

대표청구항 ▼

[ What is claimed is:] [1.]1. A ventilator for ventilating a subject with breathing gas, said ventilator comprising:a breathing circuit containing breathing gas for the subject, a portion of the breathing gas being respired by the subject, said portion being provided from the breathing circuit to th

[ What is claimed is:] [1.]1. A ventilator for ventilating a subject with breathing gas, said ventilator comprising:a breathing circuit containing breathing gas for the subject, a portion of the breathing gas being respired by the subject, said portion being provided from the breathing circuit to the subject during inspiration and received in the breathing circuit from the subject during expiration, said breathing circuit having means for recirculating breathing gas within the circuit for operating the breathing circuit in a closed circuit mode;a bellows assembly for said breathing circuit, said bellows assembly comprising:a housing;a bellows positioned in said housing and coupled in fluid communication with said breathing circuit, said bellows receiving a quantity of breathing gas corresponding to the respired breathing gas from said breathing circuit during expiration by the subject to expand the bellows in the housing, said bellows being compressed in said housing to re-circulate breathing gas in said breathing circuit and to supply breathing gas comprising the respired portion of the breathing gas to the subject during inspiration by the subject, said bellows being movable in said housing during the expansion and compression in a path of movement extending between spaced end points in said housing, said bellows being movable in a first direction along the path of movement upon compression and returning in a second direction, opposite to the first direction, upon expansion, said bellows repetitiously assuming an expanded position in said housing in accordance with the volume of the respired breathing gas received in said breathing circuit from the subject and the amount of breathing gas present in the breathing circuit, said expanded position being intermediate said end points;a ventilation driver coupled to said housing for alternately creating pressure in said housing for compressing said bellows to provide breathing gas in the breathing circuit to the subject as the respired breathing gas portion and relieving pressure in said housing for allowing said bellows to expand to receive a quantity of breathing gas in the breathing circuit corresponding to the respired portion of the breathing gas; andsensor apparatus for determining that the volume of the respired portion of the breathing gas corresponds to a desired volume and for determining whether the amount of breathing gas in the breathing circuit has increased or decreased with respect to a given amount of breathing gas, said sensor comprising:a first sensor positioned along the path of movement of said bellows at a first point intermediate said end points which corresponds to the expanded position of said bellows when the desired volume of gas is being respired by the subject with the given amount of breathing gas in the breathing circuit, said first sensor detecting and providing an indication when said bellows is present in said housing at said first point; anda second sensor positioned along the path of movement of said bellows at a second point intermediate said end points, said second point being incrementally spaced from said first point in said second direction of movement of said bellows, said second sensor detecting and providing an indication when said bellows is present in said housing at said second point;said first and second sensors being positioned along the path of movement of said bellows such that both said first and second sensors detect and provide indications when said bellows is at said second point,an indication from said first sensor in the absence of an indication from said second sensor indicating that the volume of the respired portion of the breathing gas corresponds to the desired volume and the given amount of breathing gas is present in the breathing circuit, repetitious indications from said first sensor in the absence of indications from said second sensor indicating that the amount of breathing gas in the breathing circuit is generally not changing, indications from both said first sensor and said second sensor indicating that the amount of breathing gas in the breathing circuit is greater than the given amount, and the absence of indications from both said first sensor and said second sensor indicating that the amount of breathing gas in the breathing circuit is less than the given amount.