Pressure measurement device

• US 7,025,727 B2
• Filed: 11/29/2001
• Issued: 04/11/2006
• Est. Priority Date: 10/14/1997
• Status: Expired due to Fees

• Current Assignee: Data Sciences U K Limited (International Business Machines Corporation)
• Original Assignee: Transoma Medical, Inc.
• Inventors: Brockway, Brian P., Mills, Perry Alton, Moench, Mel Murray
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US09/997,850
• Publication Number:
  US 20020035331A1
• Time in Patent Office: 1,594 Days
• Field of Search: 600/486, 600/488
• US Class Current: 600/486
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/031 Intracranial pressure
• CPC Class Codes: A61M 2025/0003 having an additional lumen transmitting fluid pressure to the outside for measurement

Abstract

A device measures pressures in animals and humans and includes a pressure transmission catheter (PTC) filled with a pressure transmitting medium and implantable in an area in having a physiological pressure. A transducer communicates with the pressure transmitting medium to provide a pressure signal representing variations in the physiologic pressure on electrical wires. A connecting catheter carries the electrical wires to signal processing and telemetry circuitry, which transmits a telemetry signal representing the pressure signal to a receiver external to the animal or human. A housing holds the signal processing and telemetry circuitry, but the transducer is remote from the housing. The device is particularly useful in measuring venous pressure, pulmonary pressure, bladder pressure, or intracranial pressure without significant head pressure artifact and with a sufficient dynamic response. One embodiment of the PTC includes a multi-durometer stem.

Claims

1. An apparatus for measuring physiological pressure comprising:

a pressure transmitting catheter having a lumen filled entirely with a pressure transmitting viscous gel;

a transducer in communication with the pressure transmitting viscous gel to provide a pressure signal representing variations in the physiological pressure on an electrical wire;

signal processing circuitry coupled to the electrical wire to process the pressure signal; and

an implantable housing holding the signal processing circuitry and the transducer;

wherein the pressure transmitting catheter includes a first layer material surrounding the lumen and at least one additional layer of material surrounding the first layer material, wherein the at least one additional layer of material has at least one material with a different hardness than the first layer of material;

wherein the pressure transmitting catheter is sufficiently short in length so that the pressure transmitting viscous gel provides a sufficient dynamic response.

2. The apparatus of claim 1 wherein the pressure transmission catheter has a length of about 2 mm.

3. The apparatus of claim 1 further comprising telemetry circuitry located in the housing and coupled to the signal processing circuitry to provide a telemetry signal representing the pressure signal.

4. The apparatus of claim 3 wherein the telemetry circuitry transmits the telemetry signal to an external receiver.

5. The apparatus of claim 1 wherein the apparatus can be employed to measure arterial pressure, venous pressure, pulmonary pressure, bladder pressure, left ventricle pressure, or intracranial pressure.

6. The apparatus of claim 1, wherein the at least one additional layer of material comprises a polymeric material.

7. The apparatus of claim 6, wherein the first layer material comprises a first polymeric material, and the at least one additional layer of material comprises a second polymeric material.

8. The apparatus of claim 7, wherein the first layer material comprises a radiopaque material.

9. An apparatus for measuring physiological pressure comprising:

a pressure transmission catheter having a lumen filled entirely with a pressure transmitting gel and implantable in an area having a physiological pressure, wherein the pressure transmitting catheter is sufficiently short in length so that the pressure transmitting gel provides a sufficient dynamic response;

a transducer in communication with the pressure transmitting gel and coupled to an electrical wire to provide a pressure signal representing variations in the physiologic pressure on the electrical wire;

signal processing circuitry coupled to the electrical wire to receive the pressure signal and provide a signal representing the pressure signal; and

an implantable housing for holding the signal processing circuitry and transducer;

wherein the pressure transmitting catheter includes a first layer material surrounding the lumen and at least one additional layer of material surrounding the first layer material, wherein the at least one additional layer of material has at least one material with a different hardness than the first layer of material.

10. The apparatus of claim 9, wherein the pressure transmitting catheter is flexible.

11. The apparatus of claim 9 further comprising telemetry circuitry located in the housing and coupled to the signal processing circuitry to provide a telemetry signal representing the pressure signal.

12. The apparatus of claim 11 wherein the telemetry circuitry transmits the telemetry signal to an external receiver.

13. The apparatus of claim 9, wherein the at least one additional layer of material comprises a polymeric material.

14. The apparatus of claim 13, wherein the first layer material comprises a first polymeric material, and the at least one additional layer of material comprises a second polymeric material.

15. The apparatus of claim 14, wherein the first layer material comprises a radiopaque material.

16. The apparatus of claim 9 wherein the pressure transmission catheter has a length of about 2 mm.

17. An apparatus for measuring physiological pressure comprising:

a pressure transmission catheter having a lumen filled with a pressure transmitting medium and implantable in an area having a physiological pressure, wherein the pressure transmitting medium comprises a slidable plug and a low-viscosity liquid;

a transducer in communication with the pressure transmitting medium and coupled to an electrical wire for providing a signal representing variations in the physiologic pressure on the electrical wire; and

a connecting catheter carrying the electrical wire to a location remote from the transducer.

18. The apparatus of claim 17 wherein the pressure transmission catheter has a length in the range from approximately five millimeters to approximately four centimeters.

19. The apparatus of claim 17 further comprising signal processing and telemetry circuitry coupled to the electrical wire to receive the pressure signal and provide a telemetry signal representing the pressure signal.

20. The apparatus of claim 19, wherein the signal processing and telemetry circuitry transmits the telemetry signal to an external receiver.

21. The apparatus of claim 19, wherein the signal processing and telemetry circuitry is located within a housing and wherein the housing is remote from the transducer.

22. An apparatus for measuring physiological pressure comprising:

a pressure transmission catheter having a lumen filled with a pressure transmitting medium and implantable in an area having a physiological pressure, the pressure transmission catheter having a multi-durometer construction including a first layer material surrounding the lumen and at least one additional layer of material surrounding the first layer material, wherein the at least one additional layer of material has at least one material with a different hardness than the first layer of material;

a transducer in communication with the pressure transmitting medium and coupled to an electrical wire for providing a signal representing variations in the physiologic pressure on the electrical wire; and

a connecting catheter carrying the electrical wire to a location remote from the transducer;

wherein the pressure transmitting medium comprises a slidable plug and a low-viscosity liquid.

23. The apparatus of claim 22 wherein the pressure transmission catheter has a length in the range from approximately five millimeters to approximately four centimeters.

24. The apparatus of claim 23, wherein the pressure transmission catheter has a length of approximately four centimeters.

25. The apparatus of claim 23, wherein the pressure transmission catheter has a length in the range from approximately one centimeter to approximately two centimeters.

26. The apparatus of claim 23, wherein the pressure transmission catheter has a length of approximately one and a half centimeters.

27. The apparatus of claim 22 further comprising signal processing and telemetry circuitry coupled to the electrical wire to receive the pressure signal and provide a telemetry signal representing the pressure signal.

28. The apparatus of claim 27, wherein the signal processing and telemetry circuitry transmits the telemetry signal to an external receiver.

29. The apparatus of claim 27, wherein the signal processing and telemetry circuitry is located within a housing and wherein the housing is remote from the transducer.

30. The apparatus of claim 22, wherein the at least one additional layer of material comprises a polymeric material.

31. The apparatus of claim 30, wherein the first layer material comprises a first polymeric material, and the at least one additional layer of material comprises a second polymeric material.

32. The apparatus of claim 31, wherein the first layer material comprises a radiopaque material.

33. An apparatus for measuring physiological pressure comprising:

a pressure transmission catheter having a lumen filled entirely with a pressure transmitting gel and implantable in an area having a physiological pressure, wherein the pressure transmitting catheter is sufficiently short in length so that the pressure transmitting gel provides a sufficient dynamic response;

a transducer in communication with the pressure transmitting gel and coupled to an electrical wire to provide a signal on the electrical wire which represents variations in the physiologic pressure; and

an implantable transducer housing to contain the transducer,

wherein the pressure transmitting catheter includes a first layer material surrounding the lumen and at least one additional layer of material surrounding the first layer material, wherein the at least one additional layer of material has at least one material with a different hardness than the first layer of material.

34. The apparatus of claim 33, further comprising signal processing and telemetry circuitry coupled to the electrical wire to receive the pressure signal and provide a telemetry signal representing the pressure signal.

35. The apparatus of claim 34, further comprising a housing holding the signal processing and telemetry circuitry and transducer.

36. The apparatus of claim 33, wherein the electrical wire is carried within a connecting catheter carrying the electrical wire to a location remote from the transducer.

37. The apparatus of claim 36, wherein the pressure transmission catheter has a length in the range from approximately five millimeters to approximately four centimeters.

38. The apparatus of claim 37, wherein the pressure transmission catheter has a length of approximately four centimeters.

39. The apparatus of claim 37, wherein the pressure transmission catheter has a length in the range from approximately one centimeter to approximately two centimeters.

40. The apparatus of claim 37, wherein the pressure transmission catheter has a length of approximately one and a half centimeters.

41. The apparatus of claim 36, further comprising signal processing and telemetry circuitry coupled to the electrical wire to receive the pressure signal and provide a telemetry signal representing the pressure signal.

42. The apparatus of claim 41, wherein the telemetry circuitry transmits the telemetry signal to an external receiver.

43. The apparatus of claim 33, wherein the at least one additional layer of material comprises a polymeric material.

44. The apparatus of claim 43, wherein the first layer material comprises a first polymeric material, and the at least one additional layer of material comprises a second polymeric material.

45. The apparatus of claim 44, wherein the first layer material comprises a radiopaque material.

46. The apparatus of claim 33 wherein the pressure transmission catheter has a length of about 2 mm.

47. An apparatus for measuring physiological pressure comprising:

a pressure transmission catheter having a lumen filled entirely with a pressure transmitting gel and implantable in an area having a physiological pressure, wherein the pressure transmitting catheter is sufficiently short in length so that the pressure transmitting gel provides a sufficient dynamic response;

a transducer in communication with the pressure transmitting gel and coupled to an electrical wire to provide a signal on the electrical wire which represents variations in the physiologic pressure;

signal processing and telemetry circuitry coupled to the electrical wire to receive the pressure signal and provide a telemetry signal representing the pressure signal; and

an implantable housing holding the signal processing and telemetry circuitry and transducer.

48. The apparatus of claim 47, wherein the pressure transmission catheter has a length in the range from approximately five millimeters to approximately four centimeters.

49. The apparatus of claim 47, wherein the telemetry circuitry transmits the telemetry signal to an external receiver.

50. The apparatus of claim 47 wherein the pressure transmission catheter has a length of about 2 mm.

51. An apparatus for measuring physiological pressure comprising:

a pressure transmitting catheter having a lumen filled with a pressure transmitting medium;

a transducer in communication with the pressure transmitting medium to provide a pressure signal representing variations in the physiological pressure on an electrical wire;

signal processing circuitry coupled to the electrical wire to process the pressure signal; and

an implantable housing holding the signal processing circuitry and the transducer,

wherein the pressure transmitting catheter includes a first layer material surrounding the lumen and at least one additional layer of material surrounding the first layer material, wherein the first layer of material is harder than the at least one additional layer of material.

52. The apparatus of claim 51 wherein the pressure transmitting medium comprises a gel.

53. The apparatus of claim 51 wherein the pressure transmitting medium comprises a gel and a low-viscosity liquid.

54. The apparatus of claim 51, wherein the lumen is filled entirely with a pressure transmitting gel.

55. The apparatus of claim 51 further comprising telemetry circuitry located in the housing and coupled to the signal processing circuitry to provide a telemetry signal representing the pressure signal.

56. The apparatus of claim 55 wherein the telemetry circuitry transmits the telemetry signal to an external receiver.

57. The apparatus of claim 51 wherein the apparatus can be employed to measure arterial pressure, venous pressure, pulmonary pressure, bladder pressure, left ventricle pressure, or intracranial pressure.