MEDICAL FLUID SENSORS AND RELATED SYSTEMS AND METHODS

• US 20140262983A1
• Filed: 03/15/2013
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Fresenius Medical Care Holdings Incorporated (Fresenius Medical Care AG)
• Original Assignee: Fresenius Medical Care Holdings Incorporated (Fresenius Medical Care AG)
• Inventors: Tuckwell, Mark David
• Granted Patent: US 9,713,664 B2
• Time in Patent Office: Days
• US Class Current: 210/85
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61M 1/152 Details related to the interface between cassette and machine
• CPC Class Codes: A61M 1/154 with sensing means or components thereof
• CPC Class Codes: A61M 1/1562 Details of incorporated reservoirs
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1605 Physical characteristics of the dialysate fluid
• CPC Class Codes: A61M 1/1619 Sampled collection of used dialysate, i.e. obviating the need for recovery of whole dialysate quantity for post-dialysis analysis
• CPC Class Codes: A61M 1/3609 Physical characteristics of the blood, e.g. haematocrit, urea
• CPC Class Codes: A61M 1/36222 Details related to the interface between cassette and machine
• CPC Class Codes: A61M 1/36224 with sensing means or components thereof
• CPC Class Codes: A61M 1/36226 Constructional details of cassettes, e.g. specific details on material or shape
• CPC Class Codes: A61M 2205/3317 Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 2205/3324 PH measuring means
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: G01F 1/586 constructions of coils, magnetic circuits, accessories therefor G01F1/582 takes precedence; magnet; inductances; transformers; selection of materials for their magnetic properties per se H01F
• CPC Class Codes: G01N 27/023 where the material is placed in the field of a coil
• CPC Class Codes: G01N 33/49 Blood chemical methods for determining blood cell populations G01N33/5094; chemical analysis of blood groups or blood types G01N33/80

Abstract

This disclosure relates to medical fluid sensors and related systems and methods. In some aspects, a circuit includes a radio frequency coil tuned to at least one frequency and at least one switching circuit directly connected to the radio frequency coil. The radio frequency coil is characterized by a high impedance.

Claims

1. A circuit comprising:

a radio frequency coil tuned to at least one frequency, the radio frequency coil being characterized by a high impedance; and

at least one switching circuit directly connected to the radio frequency coil.

2. The circuit of claim 1 wherein the high impedance is an impedance of greater than 10K ohms.

3. The circuit of claim 1 wherein the at least one switching circuit isolates a first set of components for transmitting signals from a second set of components for receiving signals.

4. The circuit of claim 3 wherein the at least one switching circuit comprises at least one high voltage transistor.

5. The circuit of claim 4 wherein the at least one high voltage transistor comprises a transistor which maintains a switching state when a voltage of at least 100 volts is applied to an input.

6. The circuit of claim 3 comprising a low noise amplifier directly connected to the at least one switching circuit.

7. The circuit of claim 1 comprising a low noise amplifier characterized by an impedance that is ten times the impedance of the radio frequency coil.

8. The circuit of claim 1 wherein the radio frequency coil is tuned to both a first frequency and a second frequency, wherein

the first frequency is a frequency of sodium molecules, and

the second frequency is a frequency of hydrogen molecules.

9. The circuit of claim 8 comprising a first set of components for receiving signals at the first frequency, and a second set of components for receiving signals at the second frequency.

10. The circuit of claim 8 wherein the first frequency is 6.5 to 11 megahertz and the second frequency is 25 to 42 megahertz.

11. A dialysis machine comprising:

a dialysis fluid pump;

a radio frequency coil tuned to at least one frequency, the radio frequency coil being characterized by a high impedance; and

at least one switching circuit directly connected to the radio frequency coil.

12. The circuit of claim 11 wherein the high impedance is an impedance of greater than 10K ohms.

13. The circuit of claim 11 wherein the at least one switching circuit isolates a first set of components for transmitting signals from a second set of components for receiving signals.

14. The circuit of claim 13 wherein the at least one switching circuit comprises at least one high voltage transistor.

15. The circuit of claim 14 wherein the at least one high voltage transistor comprises a transistor which maintains a switching state when a voltage of at least 100 volts is applied to an input.

16. The circuit of claim 13 comprising a low noise amplifier directly connected to the at least one switching circuit.

17. The circuit of claim 11 comprising a low noise amplifier characterized by an impedance that is ten times the impedance of the radio frequency coil.

18. The circuit of claim 11 wherein the radio frequency coil is tuned to both a first frequency and a second frequency, wherein

the first frequency is a frequency of sodium molecules, and

the second frequency is a frequency of hydrogen molecules.

19. The circuit of claim 18 comprising a first set of components for receiving signals at the first frequency, and a second set of components for receiving signals at the second frequency.

20. The circuit of claim 18 wherein the first frequency is 6.5 to 11 megahertz and the second frequency is 25 to 42 megahertz.

21. The circuit of claim 11 wherein the dialysis fluid pump is a blood pump.

22. The circuit of claim 11 wherein the dialysis machine is a hemodialysis machine.