Pressure transducer apparatus with disposable dome

• US 6,117,086 A
• Filed: 04/18/1997
• Issued: 09/12/2000
• Est. Priority Date: 04/18/1996
• Status: Expired due to Term

• Current Assignee: Biosensors International Group, Ltd.
• Original Assignee: Sunscope International Incorporated
• Inventors: Shulze, John E.
• Primary Examiner(s): O'Connor, Cary
• Assistant Examiner(s): Castes, Ryan
• Application Number:
  US08/844,236
• Time in Patent Office: 1,243 Days
• Field of Search: 600/485-488, 600/561, 73/715, 73/721, 73/726-727
• US Class Current: 600/488
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/0261 Strain gauges
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/03 Detecting, measuring or recording fluid pressure within the body other than blood pressure, e.g. cerebral pressure; Measuring pressure in body tissues or organs A61B5/205 takes precedence
• CPC Class Codes: A61B 5/031 Intracranial pressure
• CPC Class Codes: A61B 5/035 Intra-uterine probes therefor
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

A physiological pressure transducer is disclosed which can be adapted for multiple uses and which employs a low cost semiconductor strain gauge sensor. The transducer is connected to a fluid-filled catheter/manometer system for measuring pressures inside a living body in areas of medical interest such as the heart, brain, uterus, or the vascular system. The catheter is coupled to the pressure transducer through a unique, disposable dome containing a shaped, compliant isolation media which is in intimate contact with the transducer diaphragm. The complete assembly is adapted for use with standard catheter flushing solutions and flush devices. An improved method of drawing blood samples by using the features of the assembly is also described.

Claims

1. A disposable dome for use in combination with a reusable sensor to form a reusable transducer assembly for measuring pressure in a fluid line coupled to a catheter inserted into a living body for making direct pressure measurements in areas within the body of medical interest, said disposable dome including a fastener arranged to releasably engage a complementary surface on the reusable sensor and discardable after a single use, said dome including an electrically and biologically isolating coupling media shaped in conjunction with the dome to form a straight through fluid filling path, and wherein said media transmits hydraulic pressure signals from a fluid-filled chamber in said dome to the reusable sensor.

2. The apparatus according to claim 1 wherein the coupling media comprises one or more elastomers in an interior cavity of the disposable dome, the elastomer forming a smooth internal path for the flow of fluid.

3. The apparatus according to claim 2 wherein the elastomer is at least in part a silicone gel.

4. The apparatus according to claim 2 wherein the elastomer is cast, cured, or formed in place within the disposable dome to form a convex pressure transmitting surface prior to assembly onto the reusable sensor.

5. The apparatus of claim 1 wherein said isolating medium is U-shaped, with the legs of the `U` pointing away from the fluid path and in the direction of the reusable sensor of the transducer.

6. The apparatus of claim 1 wherein said fastener consists of a snap together retaining mechanism which can be disengaged by pressing on the sides of the dome.

7. The apparatus according to claim 1, said assembly comprising;

a housing;

an inlet and an outlet port in the housing, having a fluid flow path extending therebetween;

a cavity in the flow path, said cavity divided into a first and a second chambers by a flexible diaphragm;

said flow path in communication with said catheter and said first chamber within said housing;

said first chamber further containing said isolating media;

said second chamber containing a compensated pressure sensor spaced from said diaphragm with one side of said pressure sensor sealingly disposed in communication with a vent hole in a surface of said chamber, said vent hole providing an ambient air pressure reference to a first side of the pressure sensor;

pressure transmissive media in said second chamber for transmitting hydraulic pressure signals from said diaphragm to a second side of the pressure sensor; and

an electrical conductor connected to the pressure sensor and extending from said housing.

8. The apparatus of claim 7, wherein the housing comprises first and second removably securable components with a first component containing the first chamber and said inlet and outlet ports adapted to be removable and disposable after a single use.

9. The apparatus of claim 7, wherein the outlet port is in fluid communication with an integral stopcock having an auxiliary port for zeroing and/or catheter fluid volume manipulation.

10. The apparatus of claim 7, wherein the flexible diaphragm comprises a membrane selected from the group consisting of polyisoprene, mylar, polyamide, stainless steel alloy, high density polyethylene, silicone rubber, and nitrile or butyl rubber.

11. The apparatus of claim 7, wherein the isolating media and the pressure transmissive media comprise dissimilar materials at their contacting surfaces, such that the isolating media and the pressure transmissive when placed in intimate sealing contact do not adhere to one another.

12. The apparatus of claim 7, wherein the diaphragm comprises a surface of the pressure transmissive media in the second chamber.

13. The apparatus of claim 12 wherein said diaphragm is formed by curing a first type of silicone elastomer, and then curing a second elastomer in contact with the first.

14. A disposable dome for use in combination with a reusable sensor to form a reusable transducer assembly for measuring pressure in a fluid line coupled to a catheter inserted into a living body for making direct pressure measurements in areas within the body of medical interest, said disposable dome portion including a fastener arranged to releasably engage a complementary surface on the reusable sensor and discardable after a single use, said dome including an electrically and biologically isolating coupling media shaped in conjunction with the dome, said assembly comprising a housing, an intlet and an outlet port in the housing, having a fluid flow path extending therebetween, and a cavity in the flow path, said cavity being divided into a first chamber and a second chamber by a flexible diaphragm, wherein said coupling media is disposed adjacent to said diaphragm to transmit hydraulic pressure signals from said first chamber to said second chamber via said diaphragm, said coupling media not comprising a diaphragm, and comprising one or more elastomers which form a smooth internal path for the flow of fluid.

15. The apparatus according to claim 14, wherein said coupling media comprises a gel.