Gas flow reversing element (1) for the use of a gas supply (14) under excess pressure, in particular inspiratory gases, for selectively generating a gas flow (8) from or to a line connector (6) which can in particular be connected to an airway of a patient, said gas flow reversing element (1) being designed as a main piece (2), the main piece (2) at least comprising an inflow region (9), a nozzle region (15) and a mixing region (16), and further a branching piece (3), the inflow region (9) connecting a pressure connector (4), for connection to the gas supply (14), to at least one closable outlet opening (5) arranged in the mixing region (16), and the branching piece (3) connecting the nozzle region (15) of the main piece (2) to the line connector (6), wherein a nozzle (7), particularly an injector nozzle, is configured and arranged in the nozzle region (15) in such a way that, a gas flow (8) flowing along a first flow path (20) through the main piece (2) from the pressure connector (4) subsequently through the inflow region (9), the flow region (28), the nozzle region (15) and through the nozzle (7) into the mixing region (16) to the outlet opening (5), with the outlet opening (5) opened, can generate a gas flow (8) in the branching piece (3) flowing along a second flow path (21) from the line connector (6) and subsequently through the branching piece (3), through the nozzle region (15) and through the mixing region (16) to the outlet opening (5), wherein the gas flow reversing element (1) further comprises a bypass (18) connecting the pressure connector (4) and the line connector (6) so that a gas flow (8) can flow along a third flow path (22) via the inflow region (9), the bypass (18) and the branching piece (3), wherein at least the bypass (18) and the flow region (28) are closable by at least one closing element (19), so that the gas flow (8) can bypass the nozzle (7) in the nozzle region (15) via the bypass (18) along the third flow path (22). The invention fur
