Dialysis system having inductive heating

• US 7,731,689 B2
• Filed: 02/15/2007
• Issued: 06/08/2010
• Est. Priority Date: 02/15/2007
• Status: Expired due to Fees

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Original Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Inventors: Johnson, Tom, Chou, Tan-Cheng, Prisco, Michael R., Ding, Yuanpang S.
• Primary Examiner(s): Lucchesi; Nicholas D
• Assistant Examiner(s): HOLLOWAY, IAN KNOBEL
• Application Number:
  US11/675,470
• Publication Number:
  US 20080200866A1
• Time in Patent Office: 1,209 Days
• Field of Search: 604 28- 30, 604/67, 428 352- 354, 525 66- 68
• US Class Current: 604/113
• CPC Class Codes: A61M 1/152 Details related to the interface between cassette and machine
• CPC Class Codes: A61M 1/153 the cassette being adapted for heating or cooling the treating fluid, e.g. the dialysate or the treating gas
• CPC Class Codes: A61M 1/155 with treatment-fluid pumping means or components thereof
• CPC Class Codes: A61M 1/156 Constructional details of the cassette, e.g. specific details on material or shape
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1605 Physical characteristics of the dialysate fluid
• CPC Class Codes: A61M 1/28 Peritoneal dialysis ; Other peritoneal treatment, e.g. oxygenation
• CPC Class Codes: A61M 2205/127 with provisions for heating or cooling
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2205/3653 by Joule effect, i.e. electric resistance
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 5/44 having means for cooling or heating the devices or media

Abstract

A medical fluid machine includes (i) a pump that pumps a medical fluid and (ii) a heater that heats the medical fluid, the heater including an electrically insulative housing, at least one flat sheet of electrically conductive material suitable for contacting the medical fluid, the sheet disposed within the insulative housing, the sheet defining a flow path for the medical fluid in which the medical fluid changes direction at least one time, a primary coil of a transformer located outside the insulative housing, the primary coil configured to induce a current into the at least one conductive sheet, creating heat that may be transferred to the medical fluid.

Claims

1. A medical fluid machine comprising:

a pump that pumps a medical fluid; and

a heater that heats the medical fluid, the heater including an electrically insulative housing, at least one flat sheet of electrically conductive material suitable for contacting the medical fluid, the sheet including a first surface and a second opposing surface, the sheet disposed within the insulative housing, the sheet defining a flow path for the medical fluid in which the medical fluid changes direction at least one time and which forces the medical fluid to contact each of the surfaces of the sheet, a primary coil of a transformer located outside the insulative housing, the primary coil configured to induce a current into the at least one conductive sheet, creating heat that may be transferred to the medical fluid.

2. The medical fluid machine of claim 1, wherein the housing defines at least one of an inlet and an outlet for the medical fluid.

3. The medical fluid machine of claim 1, wherein the at least one flat sheet includes at least one characteristic selected from the group consisting of:

(i) being a plurality of sheets disposed at least substantially parallel to one another;

(ii) forming a serpentine flow path;

(iii) being made of stainless steel;

(iv) having, at least one flow restricting baffle;

(v) having a notch allowing flow of the fluid to change direction; and

(vi) having a protective plastic film.

4. The medical fluid machine of claim 1, which includes a processor configured to control an amount of power delivered to the primary coil so that the at least one conductive sheet is heated to a temperature suitable to heat the medical fluid to a desired temperature.

5. The medical fluid machine of claim 4, wherein the processor is configured to control the power based on at least one of:

(i) the desired temperature;

(ii) a flowrate of the medical fluid;

(iii) an initial temperature of the medical fluid; and

(iv) a signal from a medical fluid temperature sensor.

6. The medical fluid machine of claim 1, wherein the heater is configured to heat medical fluid initially at a temperature of less than 10°

C. to a desired temperature of at least 35°

C., wherein a flowrate of the medical fluid is at least 150 ml/min.

7. The medical fluid machine of claim 1, which is a dialysis machine, and wherein the medical fluid is dialysate.

8. The medical fluid machine of claim 1, which includes an enclosure carrying the pump:

(i) the heater also carried by the enclosure;

or (ii) the heater located remotely from the enclosure.

9. The medical fluid machine of claim 1, which is operable with a disposable cassette, the cassette having a portion operable with the pump:

(i) the housing of the heater integrated with the cassette;

or (ii) the housing of the heater located remotely from and in fluid communication with the cassette.

10. The medical fluid machine of claim 1, wherein the housing of the heater is:

(i) at least substantially rectangular or (ii) U-shaped.

11. A medical fluid heater comprising:

an electrically insulative housing;

a heater that heats the medical fluid, the heater including an electrically insulative housing, at least one flat sheet of electrically conductive material suitable for contacting the medical fluid, the sheet including a first surface and a second opposing surface, the sheet disposed within the insulative housing such that the medical fluid contacts each of the surfaces of the sheet, the sheet defining a flow path for the medical fluid in which the medical fluid changes direction at least one time; and

a primary coil of a transformer located outside the insulative housing, the primary coil configured to induce a current into the at least one conductive sheet, creating heat that may be transferred to the medical fluid.

12. The medical fluid heater of claim 11, wherein the housing defines at least one of an inlet and an outlet for the medical fluid.

13. The medical fluid heater of claim 11, wherein the at least one conductive sheet includes at least one characteristic selected from the group consisting of:

(i) being a plurality of sheets disposed at least substantially parallel to one another;

(ii) forming a serpentine flow path;

(iii) being made of stainless steel;

(iv) having at least one flow restricting baffle;

(v) having a notch allowing flow of the fluid to change direction; and

(vi) having a protective plastic film.

14. The medical fluid heater of claim 11, which is configured to operate with a processor, the processor controlling an amount of power delivered to the primary coil so that the at least one conductive sheet is heated to bring the medical fluid to a desired temperature.

15. The medical fluid heater of claim 14, which includes a temperature sensor configured to sense a temperature of at least one of the medical fluid and the flat plate and send a corresponding signal to the processor.

16. The medical fluid heater of claim 11, wherein the housing is integrated with a disposable cassette, the cassette having a pumping portion operable with a pump of a medical device.

17. The medical fluid machine of claim 11, wherein the housing of the heater is U-shaped, the primary coil fitting between sides of the U-shaped housing.

18. The medical fluid machine of claim 17, wherein the sides of the U-shaped housing include at least one of:

(i) one of the sheets of electrically conductive material; and

(ii) a flow path for the medical fluid in which the medical fluid changes direction at least one time.

19. A medical fluid machine comprising:

a pump that pumps a medical fluid; and

a heater that heats the medical fluid, the heater including an electrically insulative housing which is at least substantially rectangular, at least one flat sheet of electrically conductive material suitable for contacting the medical fluid, the sheet including a first surface and a second opposing surface, the sheet disposed within the insulative housing, the sheet defining a flow path for the medical fluid in which the medical fluid changes direction at least one time and which forces the medical fluid to contact each of the surfaces of the sheet, a primary coil of a transformer located outside the insulative housing, the primary coil configured to induce a current into the at least one conductive sheet, creating heat that may be transferred to the medical fluid.

20. The medical fluid machine of claim 19, wherein the rectangular housing is sized to hold just enough of the at least one conductive metal sheet so that the medical fluid can flow readily throughout the housing at a flowrate of at least about 150 ml/min, and so that the medical fluid initially at a temperature of less than 10°

C. can be heated to a desired temperature of at least 35°

C.