Dialysis apparatus and method for its control
AssigneeIntermedicat GmbH
InventorsDieter Rath, Peter Seeck
Life of this patent
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Abstract
A dialysis apparatus utilizes an expansion chamber in parallel with a pump from which the chamber receives blood via a valve. During the return flow phase the pump rotates in the same direction; but, the valve is closed and a valve at the chamber outlet is opened. The pump draws blood from the chamber and transports it to a dialyzer. A control device regulates the pump and valves depending on the time integral of the pump delivery. In each phase, blood is transported until the chamber has received or discharged a predetermined volume. The pump speed is variable during operation.
Claims11
An apparatus for dialyzing blood, comprising:
- means for puncturing a blood vessel;
- a blood line, coupled to said puncturing means, branching into an arterial line and a venous line;
- means, coupled to said arterial line, having an inlet and an outlet, for pumping blood through said blood line;
- said blood line comprising a circuit disposed in parallel with said pumping means;
- first valve means, coupled to said arterial line between said pumping means and said puncturing means, for opening and closing said arterial line;
- second valve means, coupled to said venous line, for opening and closing said venous line;
- means, coupled to said blood line between said pumping means and said venous line, for dialyzing blood in said blood line;
- and,
- means, coupled to said circuit, for temporarily accumulating blood in said blood line.
A method for controlling a dialysis apparatus having a cannula;
- a blood line, coupled to said cannula, branching into an arterial line and a venous line;
- a pump, having an inlet and an outlet, coupled to said arterial line, said blood line including a circuit disposed in parallel with said pump;
- a first valve, coupled to said arterial line between said pump and said cannula;
- a second valve, coupled to said venous line;
- a dialyzer, coupled to said blood line between said pump and said venous line;
- an expansion chamber, coupled to said circuit;
- a third valve, coupled to said blood line between said outlet of said pump and said dialyzer;
- a fourth valve, coupled to said circuit between said outlet of said pump and said expansion chamber;
- and, a fifth valve, coupled to said circuit between said inlet of said pump and said expansion chamber, said method comprising:
- calculating, during an inflow phase, a first time integral of a delivery of said pump;
- comparing said first time integral with a predetermined capacity of said expansion chamber;
- closing, when said first time integral substantially equals said capacity, said first and fourth valves;
- opening, when said first time integral substantially equals said capacity, said second, third and fifth valves;
- calculating, during a return flow phase, a second time integral of a delivery of said pump;
- comparing said second time integral with said capacity of said expansion chamber;
- closing, when said second time integral substantially equals said capacity, said second, third and fifth valves;
- and,
- opening, when said second time integral substantially equals said capacity, said first and said fourth valves.
Dependencies are inferred from the claim text.