Arrangement for extracorporeal circulation of blood
AssigneeGambro Lundia AB
InventorsHelmut Hildwein, Jens Schiele, Jutta Kiener
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Abstract
Arrangement for extracorporeal circulation of blood having a generally uniform flow diameter where the risk for stagnation of blood is avoided or reduced. The arrangement comprises a generally circular cylindrical means for temporary expanding the flow diameter, a means for flow expansion (9). The means for flow expansion (9) is arranged connecting the bloodline (5) and a component (6, 8) for circulation of the blood. The means for flow expansion (9) comprises a first part with a first flow diameter, d1 and a second part downstream the first part with a second flow diameter d2 where d2/d1≧1.5. The first part has a length extension L1 and the second part has a length extension L2 where L2/L1≧0.5.
Claims36
An arrangement for extracorporeal circulation of a blood related fluid in a circuit, the circuit comprising a bloodline and at least one component for circulation of the blood related fluid having an upstream inlet to the component, wherein the circuit comprises a flow expansion, the flow expansion comprising a first part having a first flow diameter d1 and a first length extension L1 and a second part downstream the first part having a second flow diameter d2 and a second length extension L2 where d2/d1≧1.5 and L2/L1≧ is 0.5 and wherein the second flow diameter d2 is a maximum diameter of a flow passage in the second part and the diameter of the flow passage in the second part gradually expands from d1 to d2 along L2, and further wherein the flow passage in the second part includes a ledge at which the diameter d2 is abruptly changed to a smaller flow diameter, said ledge disposed upstream of the inlet of the component.
A flow expansion device for an extracorporeal blood circuit having a bloodline coupled through the flow expansion device to an inlet of a component of the blood circuit, the flow expansion device comprising:
- an upstream flow passage having a flow diameter d1 and a length L1;
- a downstream flow passage having a length L2, where L2/L1≧0.5, wherein the downstream flow passage gradually increases in diameter from d1 to d2, and d2/d1≧1.5, and
- wherein the flow passage in the downstream flow passage includes an abrupt diameter change from d2 to a flow diameter of no greater than d1 no greater than d1, said abrupt change happening upstream of the component inlet.
A method to induce turbulence in blood flow through a blood passage in an extracorporeal blood circuit, wherein the blood passage includes a flow expansion device and a blood treatment component, the method comprising:
- withdrawing blood from a patient into the blood passage;
- moving the withdrawn blood in a laminar flow through the blood passage and to the flow expansion device;
- maintaining the blood in the laminar flow as the blood passes through an upstream flow passage of the flow expansion device having a constant flow diameter d1 and a length L1;
- moving the blood through a gradually increasing diameter of the flow expansion device in a downstream flow passage of the flow expansion device, wherein the diameter increases from d1 to d2, wherein d2/d1≧1.5 and the length L2 of the downstream flow passage at least 0.5 the length of L1;
- inducing turbulence in the flow of the blood passing through the downstream flow passage of the flow expansion device by passing the blood over an annular ledge formed by abruptly narrowing the flow diameter from d2 to a diameter no greater than d1;
- directing the turbulent blood flow to the blood treatment component, wherein the annular ledge is upstream of the inlet of the blood treatment component, and
- returning the treated blood from the blood treatment component to the patient.
Dependencies are inferred from the claim text.