Device and method for blood treatment with single needle operation

A device for blood treatment in a single-needle operation, comprising:

• a blood treatment unit including an inlet and an outlet;
• an extracorporeal blood circuit including a blood supply line leading to the inlet of the blood treatment unit and a blood return line departing from the outlet of the blood treatment unit;
• a blood container configured to collect blood in the extracorporeal circuit, the blood container having a closed-off volume;
• a pump configured to convey blood in the extracorporeal circuit to the blood container;
• and
• a gas container configured to store gas, the gas container having a closed-off volume,
• wherein
• the closed-off volume of the blood container is connected, via a first connection path having a valve for interrupting the connection, to the closed-off volume of the gas container in such a way that, in an arterial phase, gas expelled from the blood container during the filling of the blood container is transferred to the gas container, and
• the closed-off volume of the blood container is connected, via a second connection path having a gas compressor, to the closed-off volume of the gas container in such a way that, for the purpose of emptying the blood container in a venous phase, gas stored in the gas container is transferred by the gas compressor to the blood container,
• so that blood can be fed to the extracorporeal blood circuit in the arterial phase and blood can be removed from the extracorporeal blood circuit in the venous phase.

A method for blood treatment in a single-needle operation, wherein blood is conveyed through the blood treatment unit in an extracorporeal blood circuit, comprising:

• during an arterial phase, producing a connection, via a first connection path, between a blood container having a closed-off volume, and a gas container having a closed-off volume, and conveying blood to the closed-off volume of the blood container, whereby gas expelled from the closed-off volume of the blood container is transferred via the first connection path into the closed-off volume of the gas container, so that a pressure is built up in the gas container;
• and
• during a venous phase, producing a connection, via a second connection path, between the closed-off volume of the gas container and the closed-off volume of the blood container, and conveying gas stored in the closed-off volume of the gas container to the closed-off volume of the blood container, the blood contained in the closed-off volume of the blood container thereby being expelled,
• wherein, during the blood treatment, changing-over continuously takes place between the arterial phase, in which the volume of the blood container is filled with blood up to an upper change-over point, and a venous phase, in which the blood container is emptied to a lower change-over point,
• so that blood is fed to the extracorporeal blood circuit in the arterial phase and blood is carried away from the extracorporeal blood circuit in the venous phase.