Anesthesia rebreathing apparatus

Abstract

A general anesthesia rebreathing system comprised of a disposable portion adapted to be easily coupled to and decoupled from a permanent portion. The disposable portion includes conventional breathing tubing for coupling a source of fresh gas, as from an anesthesia machine, to a patient and in addition an overflow tube for coupling the patient end of the system to an overflow (pop-off) valve, preferably mounted on the machine and constituting part of the permanent portion. The overflow tube entrance is located close to the patient end of the system and in communication with the tubing which conveys expired gas to a reservoir, such as a conventional breathing bag, mounted at the machine end. The arrangement assures that the patient's initially expired dead space gas is conveyed by the tubing to the reservoir with subsequently expired alveolar gas being exhausted through the overflow tube and pop-off valve. By preferentially exhausting alveolar gas in this manner, the need for using CO.sub.2 absorber material within the system is minimized. For optimum performance, the pop-off valve is operable in two different modes, i.e. (1) as a manually controlled variable orifice and (2) as an automatically controlled valve responding to a positive control pressure. The source of control pressure is selectable by the attending anesthetist dependent on the type of ventilation being employed, i.e. spontaneous, manually assisted, or mechanically controlled.

Dependencies are inferred from the claim text.