A portable life support apparatus (1102) and particularly a respiratory support apparatus adapted to be easily mounted to a stretcher is disclosed. Prior devices that attach onto a stretcher are heavy and cumbersome and obstruct access to the patient. Accordingly, there is a great need for a portable emergency support device that overcomes the weight, size, positioning, and other portability disadvantages. One aspect relates to a portable life support device including at least one ambient gas inlet (14); a conditioned gas outlet (30); an oxygen concentrator (26,28) fluidly connected between the at least one gas inlet and the gas outlet, and a ventilator (44) fluidly connected downstream from the oxygen concentrator. A further aspect is directed to a portable life support apparatus in the form of a portable respiratory support apparatus (1102) capable of exploiting both ambient air and expired gas as oxygen sources, wherein the oxygen generator (20) and ventilator (10) are arranged end to end to provide a longitudinal profile that can thus be compactly secured to a stretcher or other similar emergency transport vehicle.