Device for exchanging substances between blood and at least one gas/gas mixture

A device for mass transfer between blood and at least one gas/gas mixture, comprising a first chamber configured for flow of blood therethrough and in which a first bundle of mass-permeable hollow fibers is disposed around an axially extending first core element, the device being configured for flow of a gas/gas mixture through the first bundle of hollow fibers and for flow of blood around the first bundle of hollow fibers, and a second chamber configured for flow of blood therethrough and in which a second bundle of mass-permeable hollow fibers is disposed around an axially extending second core element, the device being configured for flow of a gas/gas mixture through the second bundle of hollow fibers and for flow of blood around the second bundle of hollow fibers, the second chamber being disposed so as to follow the first chamber in a direction of the blood flow, wherein:

• the first and second chambers are disposed next to one another with a spacing between respective central axes of the first and second core elements;
• the first and the second chambers include a connecting region in an axial end region by which respective interior portions of the first and the second chambers configured for the flow of blood therethrough are connected, and
• a respective annular space is disposed around each of the first and second bundles of hollow fibers in the respective first and second chambers at the axial end region including the connecting region, the two annular spaces overlapping at the connecting region.