Device for calculating blood flow in an extracorporeal blood circuit, and an apparatus for treatment of blood using the device

• US 20050095171A1
• Filed: 10/28/2004
• Published: 05/05/2005
• Est. Priority Date: 10/29/2003
• Status: Active Grant

• Current Assignee: Gambro Lundia AB (Baxter International Inc.)
• Original Assignee: Gambro Lundia AB (Baxter International Inc.)
• Inventors: Zaccarelli, Massimo, Fressinet, Jean Louis, Artioli, Gianluca
• Granted Patent: US 7,875,168 B2
• Time in Patent Office: Days
• US Class Current: 422/44
• CPC Class Codes: A61M 1/3441 Substitution rate control as a function of the ultrafiltration rate
• CPC Class Codes: A61M 1/3663 Flow rate transducers; Flow integrators
• CPC Class Codes: A61M 1/3672 Means preventing coagulation

Abstract

The invention relates to a device for calculating blood flow and to an apparatus for extracorporeal blood treatment provided with the device. The device includes a memory for receiving and storing either a first datum relating to a blood flow removed from the patient Q_b, or a second datum relating to a flow of liquid Qt crossing a tract of the extracorporeal circuit, and a third datum relating to a flow of infusion liquid Q_inf flowing through the infusion line. The device also comprises a control unit able to calculate the first datum or the second datum as a function of the third datum relating to the flow of infusion liquid Q_inf.

Claims

1. A device for calculating blood flow in an apparatus for extracorporeal blood treatment, the apparatus comprising:

an extracorporeal circuit for circulation of blood,

first movement means for causing a flow of liquid across a predetermined tract of the extracorporeal circuit,

an infusion line connected to the extracorporeal circuit at a section thereof which is upstream of the predetermined tract, with reference to a circulation direction of blood in the extracorporeal circuit,

second movement means for causing a flow of infusion liquid across the infusion line,

the device comprising;

a memory for receiving and storing a first datum relating to the flow of blood removed from the patient (Q_b), or a second datum relating to the flow of liquid (Q_t) across the tract, the memory being able to receive and store a third datum relating to a flow of infusion liquid (Q_inf) flowing through the infusion line, a control unit, connected to the memory, which control unit is able to calculate either the first datum relating to the blood flow removed from the patient or the second datum relating to the flow of liquid across the tract, as a function of the third datum relating to the flow of infusion liquid.

2. The device of claim 1, wherein the memory is predisposed to receive and store the first datum relating to the blood flow removed from the patient (Q_b), the control unit being able to calculate the second datum, relating to the flow of liquid (Q_t) across the tract, as a function of the third datum relating to the relating to the flow of infusion liquid (Q_inf) and as a function of the first datum.

3. The device of claim 2, wherein:

the first datum comprises a set value (Q_bs) of the blood flow (Q_b) removed from the patient,

the second datum comprises a calculated value (Q_tc) of the flow of liquid crossing the tract, and

the third datum comprises a set value (Q_infs) of the infusion flow, and the control unit is able to determine the calculated value of the liquid flow using equation Qtc=Qinfs+Qbs.

4. The device of claim 2, wherein

the first datum comprises a set value (Q_bs) of the blood flow (Q_b) removed from the patient,

the second datum comprises a calculated value (Q_tc) of the flow of liquid crossing the tract, and

the third datum compries a actual value (Q_infr) of the infusion flow, and the control unit is able to determine the calculated value of the liquid flow using equation Q_tc=Q_infr+Q_bs.

5. The device of claim 3 or 4, comprising first sensor means connected to the control unit and predisposed to emit a first signal relating to a actual value (Q_tr) of the flow of liquid across the tract.

6. The device of claim 5, wherein the control unit is programmed to receive the first signal and to cooperate with the first movement means in order to bring the actual flow of liquid (Q_tr) across the tract towards the calculated value (Q_tc) of the liquid flow.

7. The device of claim 3 or 4, wherein second sensor means are provided, connected to the control unit and predisposed to provide a second signal relating to a actual value (Q_infr) of the flow of liquid crossing the infusion line.

8. The device of claim 3, wherein the control unit is programmed to cooperate with the second movement means in order to bring the actual flow of infusion liquid towards the set value (Q_infs).

9. The device of claim 7, wherein the control unit is programmed to cooperate with the second movement means in order to bring the actual flow of infusion liquid towards the set value (Q_infs).

10. The device of claim 1, wherein the first datum comprises a actual value of the blood flow removed from the patient (Q_br), the second datum comprises a actual value of the flow of liquid (Q_tr) across the tract and the third datum comprises a actual value of the infusion flow (Q_infr).

11. The device of claim 1 or 10, comprising:

first sensor means, connected to the control unit, for emitting a first signal relating to a actual value (Q_tr) of the liquid flow crossing said tract, second sensor means, connected to the control unit, for supplying a second signal relating to a actual value (Qi_infr) of the liquid flow through the infusion line, the control unit being programmed to calculate a actual value of the blood flow removed from the patient (Q_br) using equation Q_br=Q_tr−

Q_infr.

12. The device of claim 1, wherein the memory is predisposed to receive and store the second datum relating to the flow of liquid (Q_t) across said tract, said control unit being able to determine the first datum, relating to the blood flow removed from the patient (Q_b), as a function of the third datum relating to the flow of infusion liquid (Q_inf) and of the first datum.

13. The device of claim 12, wherein:

the first datum comprises a calculated value (Q_bc) of the blood flow (Q_b) removed from the patient,

the second datum comprises a set value (Q_ts) of the flow of liquid crossing the tract,

the third datum comprises a set value (Q_infs) of the infusion flow, and the control unit is able to determine the calculated value (Q_bc) of the flow of blood removed from the patient using equation Q_bc=Q_infs+Q_ts.

14. The device of claim 12, wherein:

the first datum comprises a calculated value (Q_bc) of the flow of blood (Q_b) removed from the patient,

the second datum comprises a set value (Q_ts) of the flow of liquid crossing the tract, and

the third datum comprises a actual value (Q_infr) of the infusion flow, and the control unit is able to determine the calculated value (Q_bc) of the flow of blood removed from the patient using equation Q_bc=Q_infr+Q_ts.

15. The device of claim 13 or 14, comprising first sensor means connected to the control unit and predisposed to emit a first signal relating to a actual value (Q_tr) of the flow of liquid crossing said tract.

16. The device of claim 5, wherein the control unit is programmed to receive the first signal and to cooperate with the first movement means for bringing the actual liquid flow (Q_tr) across said tract towards the set value (Q_ts) of the flow of liquid.

17. The device of claim 13 or 14, wherein second sensors are provided, which second sensor means are connected to the control unit and are predisposed to provide a second signal relating to a actual value (Q_infr) of the flow of liquid crossing the infusion line.

18. The device of claim 16, wherein

the first datum comprises a calculated value (Q_bc) of the blood flow (Q_b) removed from the patient,

the second datum comprises a set value (Q_ts) of the flow of liquid crossing the tract,

the third datum comprises a set value (Q_infs) of the infusion flow, and the control unit is able to determine the calculated value (Q_bc) of the flow of blood removed from the patient using equation Q_bc=Q_infs+Q_ts, and wherein

the control unit is programmed to cooperate with the second movement means for bringing the value of the actual flow of infusion liquid towards the set value (Q_infs).

19. The device of claim 16, wherein the control unit is programmed to cooperate with the first movement means and the second movement means for bringing the actual value of the flow of liquid (Q_tr) towards the set value.

20. The device of claim 7, wherein the control unit is programmed to cooperate with the second movement means for bringing the actual flow of the flow of liquid (Q_tr) across said tract towards the set value (Q_ts) or towards the calculated value of the flow of liquid across the same tract.

21. The device of claim 18, wherein the control unit is programmed to cooperate with the second movement means for bringing the actual flow of the flow of liquid (Q_tr) across said tract towards the set value (Q_ts) or towards the calculated value of the flow of liquid across the same tract.

22. The device of claim 20, wherein the control unit is programmed to cooperate with the first and second movement means for bringing the actual value (Q_tr) of the flow of liquid across said tract towards the set value (Q_ts) or towards the calculated value (Q_tc) of the flow of liquid across the same tract.

23. The device of claim 21, wherein the control unit is programmed to cooperate with the first and second movement means for bringing the actual value (Q_tr) of the flow of liquid across said tract towards the set value (Q_ts) or towards the calculated value (Q_tc) of the flow of liquid across the same tract.

24. The device of claim 1, wherein the device comprises a user interface connected to the control unit, the user interface being predisposed to display at least one value of the following values:

set value (Qbs) of blood flow (Qb) removed from patient,

set value (Qts) of liquid flow crossing the tract,

set value (Qinfs) of infusion flow.

calculated value (Qtc) of liquid flow crossing the tract,

calculated value (Qbc) of blood flow (Qb) removed from the patient,

actual value (Qbr) of blood flow (Qb) removed from the patient,

actual value (Qtr) of liquid flow crossing the tract,

actual value (Qinfr) of infusion flow.

25. The device of claim 24, wherein the user interface is predisposed to receive in input at least one value of the following values which can be pre-set by a user:

set value (Qbs) of blood flow (Qb) removed from patient,

set value (Qts) of liquid flow crossing the tract,

set value (Qinfs) of infusion flow.

26. The device of claim 1, wherein the control unit is programmed to receive and store in the memory at least one value from the following values:

a desired value relating to a quotient between the infusion flow (Qinf) and the flow of blood removed from the patient (Q_b), the value being fixed or obeying a pre-set time rule, or

a desired value relating to a quotient between the infusion flow (Qinf) and the flow of liquid crossing the tract, the value being fixed or according to a pre-set time rule.

27. The device of claim 26, wherein the user interface enables the user to change at least one value of the following values during the extracorporeal treatment:

set value (Qbs) of blood flow (Qb) removed from patient,

set value (Qts) of liquid flow crossing the tract,

set value (Qinfs) of infusion flow in the control unit,

the control unit being programmed to cooperate with at least one of the first and second movement means for maintaining the quotient between the infusion flow (Qinf) and the blood flow removed from the patient (Q_b) at a level corresponding to a respective desired value.

28. The device of claim 26, wherein the user interface enables the user to change at least one value of the following values during the extracorporeal treatment:

set value (Qbs) of blood flow (Qb) removed from patient,

set value (Qts) of liquid flow crossing said tract,

set value (Qinfs) of infusion flow in the control unit,

the control unit being programmed to cooperate with at least one of the first and second movement means for maintaining the quotient between the infusion flow (Qinf) and the flow of liquid crossing the tract at a level corresponding to a respective desired value.

29. The device of claim 1, wherein the infusion liquid comprises anticoagulant.

30. An apparatus for extracorporeal blood treatment, comprising:

an extracorporeal circuit for circulation of blood,

first means of movement for causing a flow of liquid across a predetermined tract of the extracorporeal circuit,

an infusion line connected to the extracorporeal circuit at a section thereof located upstream of the tract with reference to a blood circulation direction in the extracorporeal circuit,

second movement means for causing a flow of infusion liquid across the infusion line,

a blood flow calculation device according to claim 1.

31. The apparatus of claim 30, wherein the extracorporeal circuit comprises:

at least one blood treatment unit having a first chamber and a second chamber seprarated by a semi-permeable membrane,

at least a blood removal branch having an end destined to be connected with a cardiovascular system of a patient and another end in communication with an inlet of the first chamber,

at least a return branch of the blood, having an end destined to be connected to a cardiovascular system of a patient and another end in communication with an outlet of the first chamber.

32. The apparatus of claim 31, wherein the first movement means comprise a first pump which is active on the tract and which operates on the blood removal branch.

33. The apparatus of claim 31, wherein the second movement means comprise a second pump operating on the infusion line.

34. The apparatus of claim 29, wherein the infusion line comprises at least one container of a liquid to be infused.

35. The apparatus of claim 34, wherein the second sensors comprise a weight sensor operatively associated to the container and predisposed to send a signal to the control unit, which corresponds to an updated weight of the container.

36. The apparatus of claim 30, wherein the first sensor means comprises a liquid flow sensor associated to the blood removal branch, and located downstream of a section of connection between the infusion line and the extracorporeal circuit.

37. The apparatus of claim 32, wherein the first sensor means comprise a velocity sensor associated to the first movement means and able to send a signal to the control unit which signal relates to an angular velocity of the first movement means.

38. The apparatus of claim 35, wherein the control unit is programmed to calculate the actual value of the flow of liquid (Qtr) across said tract as a function of the signal relating to the angular velocity of the first movement means, a signal relating to an existing pressure upstream of the tract, of geometric characteristics of the blood removal branch and of a time variable.