Reduced size catheter tip measurement device

• US 5,902,248 A
• Filed: 11/06/1996
• Issued: 05/11/1999
• Est. Priority Date: 11/06/1996
• Status: Expired due to Term

• Current Assignee: Millar Instruments
• Original Assignee: Millar Instruments
• Inventors: Smith, Richard Alan, Millar, Huntly D.
• Primary Examiner(s): Peffley, Michael
• Assistant Examiner(s): YARNELL, BRYAN KEITH
• Application Number:
  US08/744,478
• Time in Patent Office: 916 Days
• Field of Search: 600/488, 600/485, 600/486, 600/561, 73/720, 73/721, 73/726, 73/727, 73/777, 73/715
• US Class Current: 600/485
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61B 8/445 Details of catheter construction
• CPC Class Codes: A61M 2025/0002 with a pressure sensor at the distal end
• CPC Class Codes: A61M 25/00 Catheters; Hollow probes dilators A61M29/00; peritoneal catheters A61M1/285; tracheal tubes A61M16/04; for drainage A61M27/00; for uterus, vagina or rectum A61M31/00 ; for measuring or testing A61B; materials for catheters A61L29/00

Abstract

A device that contemplates a unique and advantageous reduced size catheter tip measurement device. By using a bottom support member and a thin outer insulating layer, rather than a tubular metal casing, to support and isolate the electrical measurement sensor, the present invention drastically reduces feature size possible with current structures for catheter tip measurement devices. More specifically, the device contemplates a reduced size catheter tip pressure transducer device. The device includes a catheter body that has a support member attached to its distal tip. The support member has a support surface for a semiconductor pressures sensor that provides mechanical stability to the pressure sensor. The exposed electrical and metal areas of the device are insulated from surrounding tissues and fluids by an outer insulating layer, which is preferably a polyimide sleeve. Utilizing the device catheter tip pressure transducers may be constructed having approximately half the current volume size of prior devices. This drastic reduction is size allows for placement inside small diameter lumens of catheters, small diameter veins and arteries, or other small biological features that have up to now been too small for high-fidelity measurements by prior catheter tip pressure transducers.

Claims

1. A catheter tip pressure transducer device, comprising:

a catheter body having at least one internal lumen providing access to an external reference pressure;

at least one electrode disposed adjacent a distal end of said catheter body;

a support member coupled to a distal tip of said catheter body, said support member having a support surface, wherein said support member comprises metal, and wherein a portion of said support member comprises said at least one electrode;

a venting channel disposed within said support surface of said support member in communication with said at least one internal lumen of said catheter body;

a semiconductor pressure sensor having a diaphragm with a sensing side and a reference side, said pressure sensor being supported by said support surface of said support member and positioned relative to said venting channel so that said reference side of said diaphragm is in communication with said venting channel;

a flexible insulating material disposed over said sensing side of said diaphragm of said pressure sensor; and

an outer insulating layer covering exposed areas of said pressure sensor except for said diaphragm of said pressure sensor.

2. The catheter tip pressure transducer device of claim 1 further comprising at least one additional electrode disposed in said catheter body.

3. The catheter tip pressure transducer device of claim 1, wherein said outer insulating layer surrounds the distal tip of said device including said support member and said pressure sensor.

4. The catheter tip pressure transducer device of claim 3, wherein said outer insulating layer comprises a polyimide sleeve.

5. The catheter tip pressure transducer device of claim 1, wherein said support surface of said support member is a generally planar support surface.

6. The catheter tip pressure transducer device of claim 1, wherein said support surface of said support member comprises the top of a generally U-shaped member.

7. The catheter tip pressure transducer device of claim 1, wherein said support member comprises a tubular metal casing including a generally U-shaped portion providing said support surface with said venting channel.

8. The catheter tip pressure transducer device of claim 7, wherein said generally U-shaped portion is disposed adjacent a distal end of said tubular metal casing.

9. The catheter tip pressure transducer device of claim 1, wherein said outer insulating layer is a polyimide material.

10. The catheter tip pressure transducer device of claim 1, wherein the width of said support surface of said support member is approximately the width of said semiconductor pressure sensor.

11. The catheter tip pressure transducer device of claim 1, wherein a distal tip of said device has an outer diameter of approximately the width of said semiconductor pressure sensor.

12. The catheter tip pressure transducer device of claim 1, wherein a distal tip of said device has an outer diameter of approximately 0.018 inches or less.

13. The catheter tip pressure transducer device of claim 1, further comprising an epoxy bead coupled to a tip of said support member.