Device for controlling a system for transporting blood, and method for transporting blood in a blood line of an extracorporeal blood circuit of an extracorporeal blood treatment device

An extracorporeal blood treatment apparatus comprising:

• a device for transporting blood in a blood conduit of an extracorporeal blood circuit that has an arterial blood conduit leading to a blood treatment unit and a venous blood conduit leading away from the blood treatment unit;
• means for collecting blood that has a specified closed volume, said means for collecting blood being located in the venous blood conduit, and,
• an apparatus for controlling the device for transporting blood, said apparatus for controlling the device for transporting blood comprising:
• means for setting a particular volume flow for the blood flowing in the blood conduit;
• means for producing a control signal for the device for transporting blood in the blood conduit, wherein the control signal is dimensioned such that the blood in the blood conduit is transported at the specified volume flow rate;
• means for setting at least one particular pressure limit value for the blood conduit;
• means for measuring the pressure in the blood conduit;
• and
• means for comparing the pressure in the blood conduit with the at least one specified pressure limit value,
• wherein the means for producing a control signal is configured such that the control signal is produced when the specified pressure limit value in the blood conduit is reached, wherein the control signal is dimensioned such that when the blood is transported in the blood conduit, a pressure is established that conforms to the at least one pressure limit value,
• wherein the blood treatment apparatus is designed as a blood treatment apparatus for operation with one patient connection point,
• wherein the arterial blood conduit and the venous blood conduit have a common patient connection point,
• wherein the device for transporting blood is a device for producing a specified pressure in the means for collecting blood, such that blood that has collected in the means for collecting blood can be displaced from the means for collecting blood, the device for transporting blood further comprising:
• means for storing air which has a closed volume, and
• means for compressing air, which is in flow connection, via a connection path, with the means for storing air and the means for collecting blood,
• wherein air from the means for storing air can be conveyed into the means for collecting blood, thereby displacing the blood that has collected in the means for collecting blood, and
• wherein the means for producing a control signal further comprises:
• means for determining the volume of blood enclosed in a closed volume, and
• means for calculating the decrease in the closed blood volume in a given time interval.

A method for transporting blood in a blood conduit of an extracorporeal blood circuit of an extracorporeal blood treatment apparatus comprising:

• specifying a particular volume flow rate for the blood flowing in the blood conduit;
• specifying at least one particular pressure limit value in the blood conduit;
• determining the pressure in the blood conduit;
• comparing the pressure in the blood conduit with the at least one specified limit value for the pressure in the blood conduit;
• and
• transporting the blood in the blood conduit at the specified volume flow rate where the amount of pressure in the blood conduit lies below the at least one pressure limit value,
• controlling the pressure in the blood conduit so that a pressure that conforms to the at least one pressure limit value is achieved in the blood conduit,
• wherein the circuit has an arterial blood conduit leading to a blood treatment unit and a venous blood conduit leading away from the blood treatment unit,
• wherein the blood treatment apparatus is designed as a blood treatment apparatus for operation with one patient connection point, wherein the arterial blood conduit and the venous blood conduit have a common patient connection point,
• wherein during an arterial phase, blood is transported to the means for collecting blood, said means for collecting blood having a closed volume,
• wherein during a venous phase, a specified pressure is built up in the means for collecting blood, so that blood that has collected in the means for collecting blood is displaced out of the means for collecting blood,
• wherein there is continual switching over between the arterial phase and the venous phase,
• wherein during the venous phase, air is transported to the means for collecting blood with a means for compressing air, and
• wherein the means for compressing air are controlled such that in the closed volume of the means for collecting blood, a pressure is achieved such that the blood in the blood conduit is transported at the specified volume flow rate when the amount of pressure in the blood conduit lies below the limit value, and such that when the specified limit value for the pressure in the blood conduit is reached, a pressure is brought about which conforms to the limit value.