METHOD AND APPARATUS FOR SUPPLYING GAS MIXTURES TO AN IN VIVO RESPIRATORY SYSTEM

摘要

A homogenous mixture of a sedative gas and a respirating gas is supplied upon inspiratory demand to an in vivo respiratory system. The sedative gas is included in the mixture supplied to the in vivo respiratory system upon inspiratory demand essentially only if the respirating gas is simultaneously being supplied to the in vivo respiratory system. A sensor (24) detects an occurrence of negative pressure as an indication of inspiration in the in vivo respiratory system. A respirating gas supply valve (32) responsive to the sensor (24) communicates the respirating gas to the in vivo respiratory system. A second sensor detects the communication of the respirating gas to the in vivo system. A sedative gas supply valve operating in response with the second sensor allows sedative gas to be transmitted to the in vivo system along with the respirating gas in accordance with the detected supply of the respirating gas. In one embodiment the second sensor comprises a pressure to electric sensor (26) which upon detecting pressure associated with the supply of respirating gas actuates an electrically-operated sedative gas supply valve (34). In another embodiment the second sensor comprises fluidic circuitry wherein the supplied respirating gas is utilized to actuate a pneumatically-operated sedative gas supply valve (34').