Patent ID: 6951216

Claim:
Apparatus for altering the amount of CO 2 in breathing gases provided to a subject, the subject breathing in respiratory cycles each having an inspiratory phase in which inspiratory breathing gases are provided to the subject and an expiratory phase in which the subject exhales expiratory breathing gases, CO 2 being present in the expiratory breathing gases of the subject, said apparatus comprising: a conduit means having a flow path for providing inspiratory breathing gases to the subject during the inspiratory phases of the respiratory cycles and receiving expiratory breathing gases from the subject during the expiratory phases of the respiratory cycles; a gas component exchanger for taking up a quantity of CO 2 from gas passing through said exchanger and releasing CO 2 in gas passing through said exchanger; and means for selectively passing inspiration and expiration breathing gases in said conduit through said exchanger; the exchanger taking up CO 2 from the expiratory breathing gases in an expiratory phase and thereafter releasing CO 2 into the inspiratory breathing gases in an inspiratory phase to raise the concentration of CO 2 in the inspiration breathing gases provided to the subject.