Emptying a blood circuit after extracorporeal blood treatment

A control system for a blood treatment apparatus, the blood treatment apparatus comprising a fluid supply unit configured for installation of a dialyzer and a line set to thereby define a first flow circuit for conducting a fluid provided by the fluid supply unit through the dialyzer and back to the fluid supply unit, and to define a second flow circuit which is separated from the first flow circuit by a semi-permeable membrane of the dialyzer and comprises return and withdrawal lines for connection to a vascular system of a subject during a blood treatment session, said control system being configured to, subsequent to a termination of the blood treatment session:

• generate an instruction for an operator to connect the withdrawal line to a port of a container that holds a human-compatible fluid;
• operate the blood treatment apparatus, with the withdrawal line connected to the port, to push remaining blood in the second flow circuit into the vascular system of the subject through the return line while admitting the human-compatible fluid from the container into the withdrawal line;
• generate an instruction for the operator to disconnect the return line from the vascular system of the subject and re-arrange the second flow circuit to define a closed loop by connecting the return and withdrawal lines to be in fluid communication with the port of the container;
• and
• operate, in a draining phase with the closed loop including the return and withdrawal lines in fluid communication with the port of the container via a three-way manifold coupling unit, wherein the three-way manifold coupling unit comprises a first terminal fluidly connected to a first terminal connector and a second terminal fluidly connected to a second terminal connector, the blood treatment apparatus so as to first circulate residual liquid in the closed loop through the container and then to draw the residual liquid from the closed loop into the first flow circuit through the semi-permeable membrane of the dialyzer.

A method of operating a blood treatment apparatus that comprises a fluid supply unit and is configured for installation of a dialyzer and a line set to define a first flow circuit for conducting a fluid provided by the fluid supply unit through the dialyzer and back to the fluid supply unit, and to define a second flow circuit which is separated from the first flow circuit by a semi-permeable membrane of the dialyzer and comprises return and withdrawal lines for connection to a vascular system of a subject during a blood treatment session, said method comprising, subsequent to a rinseback procedure and while the withdrawal line is connected to a port of a container and when the return line has been disconnected from the vascular system of the subject:

• generating an instruction for re-arranging the second flow circuit to define a closed loop, wherein said re-arrangement comprises connecting the return and withdrawal lines in fluid communication with the port of the container through a three-way manifold coupling unit, wherein the three-way manifold coupling unit comprises a first terminal fluidly connected to a first terminal connector and a second terminal fluidly connected to a second terminal connector;
• and
• operating, in a draining phase, the blood treatment apparatus so as to first circulate residual liquid in the closed loop through the container and then to draw the residual liquid from the closed loop into the first flow circuit through the semi-permeable membrane of the dialyzer.