an expandable and compressible donor reservoir with an outer wall, an inner volume for retaining a volume of oxygen, and at least one orifice for allowing a passage of oxygen into and out of the inner volume, wherein the outer wall of the donor reservoir comprises a shell formed from a lightweight, flexible foil;

a supply conduit adapted to receive oxygen from a source of oxygen wherein the supply conduit has a first end for supplying oxygen to the donor reservoir and a second end for being fluidically connected to the source of oxygen;

an ambient pressure conduit adapted to supply oxygen along a fluid path from the donor reservoir to a recipient wherein the ambient pressure conduit has a first end in fluidic communication with the donor reservoir for receiving oxygen from the donor reservoir and a second end for being fluidically connected to the recipient;

an inflation detection system operable to detect a first condition wherein the donor reservoir is inflated with oxygen to a predetermined state of inflation and a second condition wherein the donor reservoir is below the predetermined state of inflation; and

a valve system for being disposed between the source of oxygen and the donor reservoir wherein the valve system is operative when in a closed condition to prevent oxygen from flowing from the source of oxygen and into the donor reservoir when the donor reservoir is in the first condition, wherein the valve system is operative in an open condition to permit oxygen to flow from the source of oxygen and into the donor reservoir when the donor reservoir is in the second condition, and wherein the valve system and the inflation detection system are operative to maintain the volume of oxygen in the donor reservoir substantially at ambient pressure.