Patent ID: 6863067

Claim:
A tubing system for use in an anesthetic system, said tubing system comprising: a unit for adsorption and desorption of gaseous anesthetic; an expiration branch adapted for respiratory communication with a respirating subject, said expiration branch being disposed upstream of said unit for adsorption and desorption of gaseous anesthetic; and a gas volume exchanger connected in said expiration branch, said gas volume exchanger comprising an inlet and outlet, a first chamber disposed between the inlet and the outlet, a second chamber disposed between the inlet and the outlet, a switching valve for selectively placing one of said first chamber or said second chamber in fluid communication with said inlet and said outlet to form a flow path between said inlet and said outlet, and a controller for controlling switching of said switching valve dependent on respiration of said subject for isolating a carbon dioxide-free volume of gas in said first chamber at a beginning of expiration while allowing flow of expiratory gas through said second chamber, and for communicating said carbon dioxide-free volume of gas to said unit during a latter part of expiration, for making said carbon dioxide-free gas available during a next inspiration for flushing said unit of carbon dioxide without involvement of a carbon dioxide filter.