Catheter and sensor having pressure detecting function

• US 6,019,728 A
• Filed: 05/06/1997
• Issued: 02/01/2000
• Est. Priority Date: 05/08/1996
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho
• Original Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho
• Inventors: Itoigawa, Koichi, Iwata, Hitoshi
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US08/852,223
• Time in Patent Office: 1,001 Days
• Field of Search: 600/486, 600/488, 600/561, 600/505
• US Class Current: 600/486
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/0261 Strain gauges
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 5/02158 provided with two or more sensor elements

Abstract

A catheter includes a longitudinally extending catheter tube to be inserted into a body. A plurality of sensing portions are arranged in the catheter tube for detecting at least two types of pressures acting on the catheter when inserted into the body. Each sensing portion is arranged along the longitudinal direction of the catheter tube. A silicone gel transmits the two types of pressures acting in the body to each sensing portion. The two types of pressures act on each sensing portion in a radial direction of the catheter tube by way of the silicone gel.

Claims

1. A physical characteristic sensor used for detecting obstacles existing in a blood vessel and for detecting blood pressure, comprising:

a hollow elongated support member, the support member having a longitudinal axis;

a first sensing portion for detecting the obstacles;

a second sensing portion for detecting the blood pressure, each said sensing portion extending in the longitudinal direction of the support member;

said second sensing portion detecting blood pressure independently on said first sensing portion detecting obstacles and,

a transmitting means for transmitting a physical quantity representative of at least one of the physical characteristics to each sensing portion, wherein the physical quantity acts on each sensing portion through said transmitting means in a direction that is generally perpendicular to the longitudinal axis.

2. The sensor as set forth in claim 1, further comprising a substantially rectangular sensor chip made of a semiconductor, wherein said sensing portions are arranged along a longitudinal direction of the sensor chip, said sensing portions separated by a predetermined interval.

3. The sensor as set forth in claim 2, wherein each sensing portion is formed thinner than the sensor chip by etching said sensor chip.

4. The sensor as set forth in claim 3, wherein said physical quantity is pressure, and wherein each sensing portion is provided with a strain gauge, said strain gauge varying in electric resistance value thereof in accordance with strain produced by said pressure applied to each sensing portion.

5. The sensor as set forth in claim 4, wherein:

each sensing portion has a top surface and a bottom surface;

said support member includes an opening located at the distal end thereof and first and second pressure communicating holes in a circumferential wall thereof, wherein the holes are respectively opposed to the top surfaces of said first and second sensing portions; and

said transmitting means includes;

a cap for closing the distal opening of the support member;

a first silicone gel for transmitting the pressure acting on the cap to the bottom surface of the first sensing portion; and

a second silicone gel arranged between the first and second through holes and the opposed top surfaces of the first and second sensing portions for transmitting the pressure about the support member to the top surfaces of the first and second sensing portions.

6. The sensor as set forth in claim 5 further comprising a first partition for blocking pressure communication between the top surface of said first sensing portion and said cap and a second partition for blocking pressure communication between the bottom surface of the first sensing portion and the rear surface of the second sensing portion.

7. A catheter used for detecting obstacles existing in a blood vessel and for detecting blood pressure, comprising:

elongated catheter tube for insertion into a body, the tube having a longitudinal axis;

a plurality of sensing portions arranged in the catheter tube to detect at least two physical characteristics acting on the catheter tube during insertion into the body, said plurality of sensing portions including a first sensing portion for detecting the obstacles and a second sensing portion for detecting the blood pressure, each sensing portion being arranged to extend in the longitudinal direction of the catheter tube;

said second sensing portion detecting blood pressure independently on said first sensing portion detecting obstacles and

a transmitting means for transmitting a pressure representing one of the two physical characteristics to each sensing portion, wherein the pressure acts through the transmitting means on each sensing portion in a direction that is perpendicular to the longitudinal axis of the catheter tube.

8. The sensor as set forth in claim 7, comprising a substantially rectangular sensor chip made of a semiconductor, wherein said sensing portion is arranged along a longitudinal direction of the sensor chip with a predetermined interval therebetween.

9. The catheter as set forth in claim 8 wherein each sensing portion is formed thinner than said sensor chip by etching the sensor chip.

10. The catheter as set-forth in claim 9 further comprising a seat for supporting said sensor chip.

11. The catheter as set forth in claim 9 wherein each sensing portion is provided with a strain gauge, said strain gauges varying in electric resistance value in accordance with strain produced by said pressures applied to each sensing portion.

12. The catheter as set forth in claim 11, wherein:

each sensing portion has a top surface and a bottom surface;

said catheter tube includes an opening located at the distal end thereof, and first and second pressure communicating holes provided in a circumferential wall thereof and respectively opposed to the top surfaces of said first and second sensing portions; and

said transmitting means includes;

a cap for closing the distal opening;

said seat having a through hole opposed to the rear surface of the first sensing portion;

a first silicone gel for transmitting pressure acting on said cap to the bottom surface of said first sensing portion through the through hole of said seat; and

a second silicone gel arranged between the first and second pressure communicating holes and the top surfaces of said first and second sensing portions for transmitting a pressure representing the blood pressure about the catheter tube to the top surfaces of the first and second sensing portions.

13. The catheter as set forth in claim 12 further comprising a first partition for blocking pressure communication between the top surface of said first sensing portion and said cap, and a second partition for blocking pressure communication between the bottom surface of said first sensing portion and the rear surface of said second sensing portion.

14. The catheter as set forth in claim 11, wherein:

said catheter tube includes an opening located at the distal end thereof and a pressure communicating hole provided in a circumferential wall thereof, wherein said pressure communicating hole is opposed to the top surface of said second sensing portion; and

said transmitting means includes;

a cap for closing the distal opening of the tube,

pressure chambers located adjacent to the bottom surfaces of said first and second sensing portions;

a first silicone gel for transmitting pressure representing forces acting on said cap to the top surface of said first sensing portion; and

a second silicone gel arranged between said pressure communicating hole and the opposed top surface of said second sensing portion for transmitting a pressure representing the pressure acting about said catheter tube to the top surface of the second sensing portion.

15. The catheter as set forth in claim 14 including a partition for blocking pressure communication between the top surface of said first sensing portion and the top surface of said second sensing portion.