Method and assembly for measuring intracranial fluid characateristics

• US 5,191,898 A
• Filed: 05/05/1992
• Issued: 03/09/1993
• Est. Priority Date: 10/22/1990
• Status: Expired due to Term

• Current Assignee: Millar Instruments
• Original Assignee: Millar Instruments
• Inventors: Millar, Huntly D.
• Primary Examiner(s): Hindenburg, Max
• Assistant Examiner(s): Tucker, Guy V.
• Application Number:
  US07/878,858
• Time in Patent Office: 308 Days
• Field of Search: 128/748, 128/774, 128/760, 606/108, 606/222, 606/223, 606/224, 606/148, 606/150, 604/8, 604/27, 604/93, 604/158, 604/160, 604/161, 604/164, 604/166, 604/264, 604/272, 604/280, 604/282, 604/283, 604/284
• US Class Current: 600/561
• CPC Class Codes: A61B 10/0045 Devices for taking samples of body liquids devices for taking blood samples A61B5/15
• CPC Class Codes: A61B 5/031 Intracranial pressure
• CPC Class Codes: A61M 25/01 Introducing, guiding, advancing, emplacing or holding catheters A61M25/10 takes precedence
• CPC Class Codes: A61M 25/0102 Insertion or introduction using an inner stiffening member, e.g. stylet or push-rod

Abstract

A method and assembly is provided which allows measurement of intracranial fluid charateristics at the intracranial region of the brain. The invention contemplates a method of implanting a ventricular catheter having one end residing in the ventricular region and the other end exiting the cranial region at a distal location. A grooved needle allows placement of a transducer tipped catheter and rerouting of both the ventricular, in-dwelling catheter and the transducer tipped catheter placed within the in-dwelling catheter. Intracranial fluid characteristics are monitored by an electrically coupled distal monitor. Further, access to the intracranial fluid is also provided to allow either short-term or long-term withdrawal or injection of intracranial fluid.

Claims

1. An assembly for measuring the fluid characteristics in a region of intercranial fluid, comprising:

a flexible in-dwelling catheter having a proximal end and a distal end, the distal end having a plurality of openings, wherein the distal end of the in-dwellings catheter is adapted to be placed in communication with said intracranial fluid through a passage in the skull;

a grooved stainless steel needle adapted to be routed subdermally between the scalp and skull from said passage to an exit point spaced from said passage, and having a proximal end removably attachable to the proximal end of said in-dwelling catheter and a distal end having a beveled point, wherein the distal end of the in-dwelling catheter and the distal end of the needle extend in opposite directions when the two elements are connected;

a transducer tipped catheter to measure fluid characteristics in a region of intracranial fluid, dimensioned to be positioned through said exit point, through the groove of said needle and to reside within the distal end of said in-dwelling catheter;

means for connecting said needle to the proximal end of said in-dwelling catheter, so that the needle and the proximal end of said in-dwelling catheter can be drawn out of said exit point; and

a monitor to analyze fluid characteristics in a region of intracranial fluid, the monitor being electrically connected to said transducer tipped catheter.

2. The assembly as recited in claim 1, wherein said in-dwelling catheter comprises a radiopaque silicone rubber tubing open at the proximal end to accommodate said transducer tipped catheter and closed at the distal end except for said plurality of openings, said transducer tipped catheter having a smaller diameter than said silicone rubber tubing.

3. The assembly as recited in claim 1, wherein said openings are arranged along the side of the distal end of said catheter and are of sufficient diameter to permit flow of fluid.

4. The assembly as recited in claim 1, wherein said needle is shapeable to extend subdermally between the scalp and skull from said passage to said exit point.

5. The assembly as recited in claim 1, wherein the proximal end of said needle comprises a male fitting with snap-fit serration thereon.

6. The assembly as recited in claim 1, wherein the proximal end of said needle comprises a male fitting with detents thereon.

7. The assembly as recited in claim 1, wherein the proximal end of said needle comprises a male fitting with threads thereon.

8. The assembly as recited in claim 1, wherein the proximal end of said in-dwelling catheter comprises a female fitting with serrations thereon.

9. The assembly as recited in claim 1, wherein the proximal end of said in-dwelling catheter comprises a female fitting with detents thereon.

10. The assembly as recited in claim 1, wherein the proximal end of said in-dwelling catheter comprises a female fitting with threads thereon.

11. The assembly as recited in claim 1, wherein the proximal end of said needle and the proximal end of said in-dwelling catheter are releasably pushable together.

12. The assembly as recited in claim 1, wherein the proximal end of said needle and the proximal end of said in-dwelling catheter are releasably rotatable together.

13. The assembly as recited in claim 1, wherein said exit point is positioned at a substantially distant location from said passage.

14. The assembly as recited in claim 1, wherein said exit point is located at a point substantially distant from the cranial region to thereby operate as a shunt for directing intracranial fluid into the vascular system.

15. The assembly as recited in claim 1, further comprising an adaptor means which is coupled to the proximal end of said in-dwelling catheter for allowing access to said intracranial fluid after said catheter is separated from said needle.

16. The assembly as recited in claim 15, wherein said adaptor means comprises a Luer-Lok coupling to said in-dwelling catheter.

17. The assembly as recited in claim 15, wherein said adaptor means comprises a Y-shaped body with one arm of the Y-shaped body having a stopcock for accessing said fluid and the other arm of the Y-shaped body having a seal means for preventing infection from entering said intracranial fluid via transducer tipped catheter extending therethrough.

18. The assembly as recited in claim 1, additionally comprising a stylet for inserting said in-dwelling catheter into the intracranial fluid.

19. The assembly as recited in claim 1, wherein said transducer tipped catheter comprises a strain gauge and electrically connected wires for measuring hemodynamics and pressure waveforms of said intracranial fluid.

20. The assembly as recited in claim 1, wherein said groove is dimensioned to accommodate the diameter of said transducer tipped catheter.

21. The assembly as recited in claim 1, wherein said means for connecting said needle to the proximal end of said in-dwelling catheter is releasable.