Method and apparatus for calibrating pacemaker pressure sensor lead prior to chronic implant

• US 5,919,221 A
• Filed: 04/22/1997
• Issued: 07/06/1999
• Est. Priority Date: 04/22/1997
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Miesel, Keith A.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): Evanisko, George R.
• Application Number:
  US08/837,674
• Time in Patent Office: 805 Days
• Field of Search: 73/1.57-1.63, 73/1.66-1.71, 607/27, 607/119, 607/122, 607/23, 600/488
• US Class Current: 607/119
• CPC Class Codes: A61B 2560/0257 using atmospheric pressure
• CPC Class Codes: A61B 5/02156 Calibration means
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence

Abstract

The present invention provides apparatus, systems, and methods for accurately calibrating a pressure sensor which is incorporated into a lead, e.g., a pacemaker lead, prior to implant into a patient. A calibration vessel is provided which has a housing which forms a reservoir for containing the portion of the lead having the pressure sensor. The vessel also has a connector for receiving a reference pressure into the reservoir, and a sealable opening for receiving the distal end of the lead that carries the pressure sensor. The calibration vessel can be used in a system comprising an electronic display module and an external pressure reference, for establishing an accurate sensor baseline for zero pressure; and can also be used in a system comprising an electronic display module, a reference pressure input source, and a manometer for establishing an accurate scale factor for the lead pressure sensor.

Claims

1. A calibration vessel adapted for use in a sterile environment, for baseline and scale factor calibration of a lead pressure sensor having a pressure sensor located on a distal end thereof, comprising:

a vessel having a proximal end, a distal end, and an interior reservoir for containing said lead distal end;

said proximal end of said vessel having sealable opening means for admitting said lead distal end into said reservoir while providing an airtight seal between said reservoir and the exterior of said vessel; and

said distal end of said vessel having connecting means for providing a connection between said vessel reservoir and a pressure input source, and wherein said vessel further comprises a housing which is adapted and disposed to be affixed to said lead distal end and wherein said vessel housing comprises a peel-away material adapted to peel-away from said lead.

2. The vessel of claim 1 wherein said vessel comprises a tubular housing which forms said reservoir.

3. The vessel of claim 2, wherein said sealable opening means comprises a rubber seal, and said connecting means comprises a leur-lock interface.

4. The vessel of claim 1, and wherein said sealable opening means is sized to admit said lead distal end.

5. The combination of a pressure sensor calibration system and a lead, said lead having a sensor at about its distal end which provides an electrical output representative of a body parameter, and an electrical connection from said sensor output to the lead proximal end, said combination comprising:

said lead having a distal end comprising a pressure sensor and a proximal end, oppositely located from said distal end,

a calibration vessel for containing said lead distal end, said vessel having a vessel housing with a proximal end and a distal end, said vessel housing forming a vessel reservoir for containing said lead distal end, said proximal end of said vessel housing having sealing means for providing an airtight seal between said vessel reservoir and said lead, and said distal end of said vessel housing having connecting means for providing a connection between said reservoir to a pressure external to said reservoir; and

an electronic display module electrically connected to said lead proximal end to receive and display said sensor output and wherein said lead is a pacemaker lead, and said sensor is a pressure sensor.

6. The combination of a pressure sensor calibration system and a lead, said lead having a sensor at about its distal end which provides an electrical output representative of a body parameter, and an electrical connection from said sensor output to the lead proximal end, said combination comprising:

said lead having a distal end comprising a pressure sensor and a proximal en, oppositely located from said distal end,

a calibration vessel for containing said lead distal end, said vessel having a vessel housing with a proximal end and a distal end, said vessel housing forming a vessel reservoir for containing said lead distal end, said proximal end of said vessel housing having sealing means for providing an airtight seal between said vessel reservoir and said lead, and said distal end of said vessel housing having connecting means for connecting said reservoir to a pressure external to said reservoir; and

an electronic display module electrically connected to said lead proximal end to receive and display said sensor output,

said system further comprising;

an external pressure reference which provides an electrical signal representative of atmospheric pressure, said atmospheric signal being electrically connected to said electronic display module; and

said electronic display module providing an output indication of the difference between said sensor output and said atmospheric signal.

7. The combination as described in claim 6, further comprising an external pressure source connected to said connecting means.

8. The combination as described in claim 6, wherein said vessel housing is a tube, said sealing means is a rubber seal, and said connecting means is a leur-lock interface.

9. The combination of as described in claim 6, wherein said vessel housing comprises peel-away material adapted to peel-away from said pacemaker lead.

10. A method of establishing an accurate baseline for a pressure sensor incorporated into a lead for use with an implantable medical device, said lead having said sensor located at its distal end and an output from said sensor located at its proximal end, comprising:

providing a calibration vessel which has an interior reservoir for containing said distal end of said pacemaker lead, said vessel having a proximal end and a distal end;

inserting said lead distal end through said vessel proximal end so that said lead distal end is sealed within said reservoir at said vessel proximal end;

opening said vessel reservoir at said vessel distal end to atmospheric pressure;

providing a display means for displaying a differential of two electrical signals connected thereto;

connecting a first electrical signal representative of atmospheric pressure to said display means, to provide a first of said two electrical signals;

connecting said sensor output from said lead proximal end to said display means, to provide a second of said two electrical signals; and

adjusting said sensor so that said display means displays a substantially zero differential.

11. A method of calibrating a pressure sensor incorporated into a pacemaker lead, said lead having said sensor located at its distal end and an output from said sensor at its proximal end, comprising:

providing a calibration vessel which has an interior reservoir for containing said distal end of said pacemaker lead, said vessel having a proximal end and a distal end;

inserting said lead distal end through said vessel proximal end so that said lead distal end is sealed within said reservoir at said vessel proximal end;

providing a known pressure to said vessel reservoir;

providing a display means for displaying an indication of a value represented in an electrical signal;

connecting said sensor output from said lead proximal end to said display means so as to supply an electrical signal representative of sensor output from said lead to said display means; and

adjusting said sensor so that said display indication accurately corresponds to said known pressure.

12. A combination of a lead for connection to a medical device and a calibration vessel, comprising:

said lead having a distal end and a proximal end, said lead comprising at least one electrode positioned at about said lead distal end, a pressure sensor incorporated into said lead near said lead distal end, and connecting means for electrically connecting said sensor to a sensor output at said lead proximal end, and said electrode to an electrode terminal at said lead proximal end; and

said calibration vessel being adhered to a distal portion of said lead, said vessel having a reservoir in which said sensor is enclosed, seal means for sealing said vessel around said lead at a location proximal to said sensor, and pressure communicating means for communicating a given pressure to reservoir.

13. The combination as described in claim 12, wherein said vessel comprises means for peeling said vessel away from said lead.