Medical pressure sensing guide wire

• US 5,860,938 A
• Filed: 09/06/1996
• Issued: 01/19/1999
• Est. Priority Date: 03/07/1996
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Hastings, Roger N., Lafontaine, Daniel M., Talpade, Dnyanesh
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): LAYNO, CARL HERNANDZ
• Application Number:
  US08/707,829
• Time in Patent Office: 865 Days
• Field of Search: 128/637, 128/657, 128/673, 128/674, 128/675, 128/772, 600/369, 600/434, 600/486, 600/487, 600/488, 600/585
• US Class Current: 600/585
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/02158 provided with two or more sensor elements
• CPC Class Codes: A61B 5/6851 Guide wires
• CPC Class Codes: A61M 2025/09175 having specific characteristics at the distal tip
• CPC Class Codes: A61M 25/09 Guide wires

Abstract

A guide wire that is capable of sensing the phasic pressure at the distal end of the guide wire. The guide wire has a central lumen which provides a non-compliant fluid path from the distal end of the guide wire to a pressure transducer at the proximal end of the guide wire.

Claims

1. A medical pressure sensor comprising:

a body portion having a proximal end, a distal end, and a lumen extending therethrough for communicating pressure from the distal end of the body portion to the proximal end of the body portion, the body portion having a compliance C_f which includes the compliance of the body portion and any fluid therein; and

a transducer positioned near the proximal end of the body portion and in fluid communication with the lumen, the transducer having a compliance C_t, where the system compliance C=C_f +C_t, and the system compliance ##EQU7## where the diameter D is less than about 0.0013 meters,

the natural frequency f₀ less than about 30 Hz,

π

is a constant equal to 22/7,

ρ

is the density of the fluid in kilograms per cubic meter,

η

is the fluid viscosity in newton seconds per square meter,

L is the length of the lumen in meters, and

the system damping coefficient ξ

is less than about 3.0.

2. A pressure sensing device having a total compliance, the device comprising:

an elongate body having length of about 1-4 meters, a pressure communicating lumen extending therethrough, an inner diameter of less than about 0.0013 meters, and a proximal end; and

a transducer attached to the proximal end of the elongate body and in fluid communication with the lumen, the total compliance of the pressure sensing device less than about 4×

10^-14 m⁵ /Nt.

3. The pressure sensing device of claim 2 wherein the total compliance of the device includes the compliance of a volume of liquid disposed thereon, the volume of liquid being less than about one cubic centimeter.

4. The pressure sensing device of claim 2 wherein the total compliance of the device includes the compliance of a volume of entrapped air disposed thereon, the volume of entrapped air being less than about 0.004 cubic centimeters.

5. A method of sensing a phasic pressure signal within a body lumen comprising:

providing an elongate body having a proximal end, a distal end, a pressure communicating lumen therethrough, a fluid within the pressure communicating lumen, a transducer attached to the proximal end of the elongate body and in fluid communication with the pressure communicating lumen, and a system compliance of less than about 4×

10^-14 m⁵ /Nt, the pressure communicating lumen having a diameter of less than about 0.0013 meters;

inserting the distal end of the elongate body into the body lumen;

advancing the elongate body to a position within the body lumen; and

sensing the phasic pressure signal at that position within the body lumen.

6. The method of sensing a phasic pressure signal within a body lumen of claim 5 further comprising:

providing a catheter having a lumen therethrough; and

advancing the catheter over the elongate body after the elongate body has been advanced to the position within the body lumen.

7. The method of sensing a phasic pressure signal within a body lumen of claim 6 further comprising:

conducting a therapeutic procedure with the catheter after the catheter has been advanced to the position within the body; and

sensing the phasic pressure signal before, during or after the therapeutic procedure has been conducted.

8. The method of sensing a phasic pressure signal within a body lumen of claim 7 further comprising:

sensing the phasic pressure signal before and after the therapeutic procedure.

9. A connector suitable for removeably connecting to a medical pressure sensing instrument, the connector comprising:

a body portion having an interior and a port suitable for providing fluid communication between the medical pressure sensing instrument and the interior of the body portion, the body portion having a compliance; and

a pressure transducer attached to the body portion and in fluid communication with the interior of the body, the pressure transducer having a compliance, wherein the sum of the compliance of the body portion and the compliance of the pressure transducer is less than 4×

10^-14 m⁵ /Nt.

10. The connector of claim 9 further comprising:

a flush port in fluid communication with the interior of the body portion; and

stop cock positioned such that fluid communication between the interior of the body portion and the flush port may be blocked.

11. The connector of claim 9 wherein the pressure transducer comprises a solid state pressure transducer.

12. The connector of claim 9 wherein the pressure transducer comprises:

a light source attached to the body portion and aligned to shine through the medical pressure sensing instrument; and

a photodetector attached to the body portion and positioned to detect light shined through the medical sensing instrument.

13. The connector of claim 12 wherein the light source comprises a light emitting diode.