Inhalation anaesthesia delivery system and method

An inhalation anesthesia delivery system, comprising:

• a fresh gas feeding arrangement connected to a breathing circuit;
• a monitor device;
• a control device;
• and
• an interface unit;
• wherein the interface unit is configured to be used to input at least two set target gas concentration values including at least a set target end tidal oxygen (EtO2) concentration value and a set target end tidal volatile anesthetic agent concentration value;
• the fresh gas feeding arrangement is configured to deliver a desired concentration of gas including at least a desired concentration of oxygen to the breathing circuit;
• the monitor device is configured to monitor and measure at least two expired gas concentration values including an expired end tidal oxygen (EtO2) concentration value and an expired end tidal volatile anesthetic agent concentration value by analyzing expiration gases in the breathing circuit;
• the control device is configured to receive the at least two set target gas concentration values including the target end tidal oxygen (EtO2) concentration value and the set target end tidal volatile anesthetic agent concentration value from the interface unit, receive the at least two expired gas concentration values from the monitor device, and to provide the desired concentration of gas including at least the desired concentration of oxygen (O2) to the breathing circuit via the fresh gas feeding arrangement;
• and
• the control device is further configured to control the at least two expired gas concentration values by comparing at least the measured expired end tidal oxygen (EtO2) concentration value with the set target end tidal oxygen (EtO2) concentration value and the measured expired end tidal volatile anesthetic agent concentration value with the set target end tidal volatile anesthetic agent concentration value, and changing the desired concentration of gas including the desired concentration of oxygen delivered to the breathing circuit accordingly to meet the at least two set target gas concentration values;
• wherein, when the measured at least two expired end tidal concentration values are about equal to the at least two set target gas concentration values, the control device is further configured to reduce fresh gas flow to minimize consumption of the volatile anesthetic agent.