Abstract: A valve for an anaesthetic rebreathing system includes a valve body, a selector member situated within the valve body and a relief valve which forms an integral part of the valve. The valve can be converted from a Mapleson A to a Mapleson D configuration and from a Mapleson A or D configuration to a Mapleson E configuration.

Abstract: A valve for an anaesthetic rebreathing system includes a valve body and a valve closure member situated within the valve body. The valve can be converted between a Mapleson A and a Mapleson D configuration. The valve body includes a fresh gas inlet, a fresh gas outlet, a fresh gas conduit in communication with the fresh gas inlet and the fresh gas outlet, an expired gas inlet/outlet port, a waste gas outlet, an expired gas conduit in communication with the expired gas inlet/outlet port and the waste gas outlet, a reservoir bag inlet/outlet port and a reservoir bag conduit in communication with the reservoir bag inlet/outlet port. All the conduits converge at a node within which the valve closure member is operable to isolate the expired gas inlet/outlet port and the waste gas outlet from the reservoir bag inlet/outlet port in a first position thereof and to isolate the fresh gas inlet and the fresh gas outlet from the reservoir bag inlet/outlet port in a second position thereof.