System and technique for measuring blood characteristics by centering a sensor in an artery

• US 5,265,606 A
• Filed: 02/25/1993
• Issued: 11/30/1993
• Est. Priority Date: 07/23/1990
• Status: Expired due to Fees

• Current Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Original Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Inventors: Kujawski, Dennis
• Primary Examiner(s): ASCHENBRENNER, PETER
• Application Number:
  US08/023,174
• Time in Patent Office: 278 Days
• Field of Search: 128/772, 604/21, 604/164, 604/165, 604/280, 604/281, 604/282, 604/283, 604/268
• US Class Current: 600/341
• CPC Class Codes: A61B 5/02154 by optical transmission
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/6886 Monitoring or controlling distance between sensor and tissue
• CPC Class Codes: A61M 25/01 Introducing, guiding, advancing, emplacing or holding catheters A61M25/10 takes precedence

Abstract

A probe carrying sensor means at its distal tip is supported centrally within a blood vessel by an introducer catheter. The introducer catheter includes a percutaneously insertable shaft which is configured to engage and be supported by the inner luminal surface of the blood vessel. The distal tip of the catheter shaft is disposed along a central axis of the catheter such that when the catheter is disposed in the blood vessel, the distal tip will be disposed substantially along that axis and substantially in the center of the blood vessel lumen. The probe passed through the catheter thus will emerge from the distal outlet orifice of the catheter into the blood vessel at the central axis of the blood vessel.

Claims

1. A percutaneously insertable, needle mountable introducer catheter for guiding and supporting a probe within a blood vessel, in combination with a probe, comprising:

a tubular elongate flexible catheter shaft having a fitting at a proximal end and a distal tip segment that terminates in an outlet orifice, the tip segment being no greater in diameter than the shaft;

the inner and outer surfaces of the catheter shaft and tip segment being substantially smooth;

the catheter having a longitudinally extending central axis that extends through the fitting and the outlet orifice;

a portion of the shaft extending between the fitting and the outlet orifice including at least external portions of the shaft that are spaced transversely from the central axis at a distance sufficient for surfaces of the external portions to engage the inner luminal surface of the blood vessel to stabilize the transverse position of the catheter within the blood vessel relative to the longitudinal axis of the blood vessel; and

the distal tip segment extending substantially along the central axis; and

a probe constructed to be passed through the catheter shaft without substantially distorting said stabilizing portion of the catheter shaft,

whereby the distal end of the probe may protrude beyond the distal outlet orifice substantially along said central axis.

2. An introducer catheter and probe as defined in claim 1 wherein the catheter shaft is formed in a longitudinally extending zig-zag configuration including alternating substantially opposed apices and segments of the shaft and where the apices are displaced transversely from the central axis of the catheter.

3. An introducer catheter and probe as defined in claim 1 wherein the shaft is formed to include a longitudinally extending helically coiled segment of the shaft, the central axis extending through the helical coil.

4. An introducer catheter and probe as defined in any one of claims 1-3 wherein the catheter is sufficiently flexible to be mounted on a straight rigid needle, the shaft comprising a polymeric material having memory such that when the needle is withdrawn from a shaft, the shaft will assume said configuration in which at least external portions of the shaft are spaced transversely from the central axis of the catheter.

5. An introducer catheter and probe as defined in claim 4 further comprising, in combination with said needle;

said introducer catheter being mounted on said needle.

6. An introducer catheter and probe as defined in claim 2 wherein the apices are spaced at a substantially uniform height from the central axis of the catheter.

7. An introducer catheter and probe as defined in claim 2 wherein at least some of more distally disposed apices are spaced closer to the central axis of the catheter than apices at more proximal portions of the catheter shaft.

8. An introducer catheter and probe as defined in any one of claims 1-3, 6 or 7 wherein a top segment of the catheter shaft is tapered in a distal direction.

9. An introducer catheter and probe as defined in claim 8, the probe having a reduced diameter at a distal tip thereof, said reduced diameter being significantly smaller than the outlet orifice.

27. An introducer catheter and probe as defined in claim 1 wherein the catheter shaft has a predetermined cross-sectional radius and wherein the distance by which said external portions of the shaft are spaced transversely from the central axis of the catheter is greater than said predetermined radius.

10. A method for supporting a probe within a blood vessel at a location spaced from the luminal surface of the blood vessel comprising:

providing a catheter having;

a tubular elongate flexible catheter shaft having a fitting at a proximal end and a distal tip segment that terminates in an outlet orifice;

the catheter having a longitudinally extending central axis that extends through the fitting and the outlet orifice;

a portion of the shaft extending between the fitting and the outlet orifice including at least external portions of the shaft that are spaced transversely from the central axis at a distance sufficient for surfaces of the external portions to engage the inner luminal surface of the blood vessel to stabilize the transverse position of the catheter within the blood vessel relative to the longitudinal axis of the blood vessel; and

the distal tip segment extending substantially along the central axis; and

inserting the catheter into the blood vessel to cause the catheter to become stabilized so as to limit transverse movement of the catheter shaft in the blood vessel relative to a longitudinal axis of the blood vessel; and

thereafter advancing a probe through the catheter so that its distal tip emerges from the distal outlet orifice of the catheter in a spaced apart relationship from the inner luminal surface of the blood vessel.

11. An introducer catheter for placing a probe in substantial alignment with the central longitudinal axis of a blood vessel, in combination with said probe, comprising:

a tubular elongate flexible catheter shaft having a proximal end carrying a fitting and having a distal tip segment that terminates in an outlet orifice;

the catheter defining a longitudinally extending central axis that extends through the fitting and the outlet orifice, wherein the distal tip segment extends substantially along the central axis; and

the shaft being made of a material having a shape memory and including shaft portions spaced from the central axis for centering the distal tip segment of the shaft relative to a blood vessel lumen, wherein the shaft portions can be straightened in substantial alignment with the central axis when the shaft is mounted over a rigid needle to facilitate insertion of the shaft into a blood vessel lumen; and

a probe constructed to be passed through the catheter shaft without substantially distorting said shaft portions,

whereby the distal end of the probe may protrude beyond the distal outlet orifice of the catheter substantially along said central axis.

12. An introducer catheter and probe as defined in claim 11 wherein the means for centering includes at least two longitudinally remote zig-zag formations upon the shaft having apices that are displaced transversely from the central axis.

13. An introducer catheter and probe as defined in claim 11 wherein the means for centering includes a helically coiled shaft segment, the central axis extending through the helically coiled segment.

14. An introducer catheter and probe as defined in any one of claims 11-13 wherein the shaft comprises a polymeric material and is sized to be mounted on a straight rigid needle such that when mounted on the needle the shaft assumes a straightened shape and when removed therefrom assumes an original non-straightened shape that includes the means for centering.

15. An introducer catheter and probe as defined in any one of claims 11-13 further comprising the probe having a reduced diameter at a distal tip thereof, said reduced diameter being significantly smaller than the outlet orifice.

16. A percutaneously insertable, introducer catheter for aligning a probe within a blood vessel away from the inner luminal surface of the blood vessel and substantially along a longitudinal axis of the blood vessel, and a probe in combination therewith, comprising:

a tubular elongate flexible catheter shaft having a proximal end carrying a fitting and a distal tip segment that terminates in an outlet orifice, the tip segment being no greater in diameter than the shaft;

the inner and out surfaces of the catheter shaft and tip segment being substantially smooth;

the catheter having a longitudinally extending central axis that extends through the fitting and the outlet orifice, wherein the distal tip segment extends substantially along the central axis; and

the shaft including shaft portions extending transversely from the central axis for contacting at least two longitudinally spaced and circumferentially opposed portions of the inner luminal surface of a blood vessel to stabilize the catheter within the blood vessel radially relative to the longitudinal axis of the blood vessel; and

a probe constructed to be passed through the catheter shaft without substantially distorting said stabilizing portion of the catheter shaft,

whereby the distal end of the probe may protrude beyond the distal outlet orifice substantially along said central axis.

17. A percutaneously insertable, needle mountable introducer catheter for substantially centering a probe relative to the longitudinal axis of a blood vessel and removing the probe from contact with the inner luminal surface of the blood vessel, and a probe in combination therewith, comprising:

a tubular elongate flexible catheter shaft having a proximal end carrying a fitting and a distal tip segment that terminates in an outlet orifice, the tip segment being no greater in diameter than the shaft;

the inner and outer surfaces of the catheter shaft and tip segment being substantially smooth;

the catheter having a longitudinally extending central axis that extends through the fitting and the outlet orifice;

the shaft comprising linear segments substantially aligned with the central axis and a plurality of longitudinally spaced non-linear segments having external surfaces that extend transversely from the central axis beyond an outer diameter of the linear segments in substantially opposing directions; and

the distal tip segment extending in substantial alignment with the central axis and between the opposed non-liner segments; and

a probe constructed to be passed through the catheter shaft without substantially distorting said non-linear segments of the catheter shaft,

whereby the distal end of the probe may protrude beyond the distal outlet orifice substantially along the central axis.

18. An introducer catheter and probe as defined in claim 17 wherein the non-linear segments comprise a plurality of coplanar zig-zags.

19. An introducer catheter and probe as defined in claim 17 wherein the non-linear segments comprise portions of a helical coil.

20. An introducer catheter and probe as defined in any one of claim 17-19 wherein the shaft comprises a polymeric material having memory and being sized to be mounted on a straight rigid needle such that when mounted on a needle the shaft assumes a straightened shape and when removed therefrom assumes an original non-straightened shape including the non-linear segments.

21. An introducer catheter and probe as defined in any one of claims 17-19 wherein a tip of the catheter shaft is tapered in a distal direction.

22. An introducer catheter and probe as defined in claim 21 further comprising said probe having a reduced diameter at a distal tip thereof, said reduced diameter being significantly smaller than an inner diameter of the outlet orifice.

23. A method for positioning a probe within a blood vessel at a location spaced from the inner luminal surface of the blood vessel comprising:

providing an introducer catheter having a longitudinally extending central axis and a distal tip segment that lies along the central axis and terminates in an outlet orifice, the catheter having a tubular elongate flexible shaft of a material having shape memory including eternal portions that extend to contact the inner luminal surface of the blood vessel at a plurality of points to stabilize a distal tip segment of the shaft transversely relative to a longitudinal axis of the blood vessel so that a probe emanating from the distal tip segment is out of contact with the luminal surface and is disposed longitudinally relative to the blood vessel;

mounting the introducer catheter on a rigid needle so that the external portions of the shaft becomes substantially straight;

inserting the straightened shaft and needle through a blood vessel wall and into a blood vessel lumen;

removing the rigid needle from the shaft following insertion so that the catheter becomes transversely stabilized in the blood vessel; and

inserting a probe through the shaft so that it emerges from the distal tip segment of the catheter in a spaced apart relationship from the luminal surface of the blood vessel.

24. A percutaneously insertable, needle mountable introducer catheter for supporting a probe within a blood vessel at a location spaced from the inner luminal surface of the blood vessel, in combination with a probe, comprising:

a tubular elongate flexible catheter shaft having a proximal end, a longitudinally extending central axis, and a distal tip segment that terminates in an outlet orifice, the tip segment being no greater in diameter than the shaft;

the inner and outer surfaces of the catheter shaft being substantially smooth;

means comprising portions of the shaft and defining a plurality of spatially opposed support points spaced longitudinally along the shaft, the support points disposed transverse to the central axis so as to orient the distal tip segment in a substantially spaced apart relationship from the inner luminal surface of the blood vessel;

so that a probe emanating from the outlet orifice extends longitudinally in a spaced apart relationship from the inner luminal surface of the blood vessel; and

a probe constructed to be passed through the catheter shaft without substantially distorting said support points,

whereby the distal end of the probe may protrude beyond the distal outlet orifice substantially along said central axis.

25. An introducer catheter for supporting a probe mounted therein away from the inner luminal surface of a blood vessel having deployed and undeployed positions, in combination with a probe, comprising:

a tubular elongate flexible catheter shaft having a proximal end, a longitudinally extending central axis, and a distal tip segment that lies along the central axis and terminates in an outlet orifice;

a plurality of non-linear segments of the shaft being disposed transverse to the central axis so that in a deployed position within the blood vessel the segments engage circumferentially opposed portions of the inner luminal surface of the blood vessel with the distal tip segment supported by the segments away from the inner luminal surface of the blood vessel and wherein a probe passed through the shaft emerges from the outlet orifice extending spaced from the inner luminal surface in substantial longitudinal alignment with a line through the proximal end and the distal tip segment; and

the shaft being sized to accept a needle that causes the non-linear segments to become straightened in alignment with the needle in an undeployed position, a combination of the shaft and the needle being easily insertable into a blood vessel it he undeployed position and the needle being removable from the shaft subsequent to insertion to place the shaft in the deployed position; and

a probe constructed to be passed through the catheter shaft without substantially distorting said non-linear segments,

whereby the distal end of the probe may protrude beyond the distal outlet orifice substantially along the central axis.

26. A percutaneously insertable, needle mountable introducer catheter for supporting a probe in a spaced apart relationship from the inner luminal surface of a blood vessel without substantial reduction of blood flow therearound in the blood vessel, in combination with a probe, comprising:

a tubular elongate flexible catheter shaft having a proximal end, a longitudinally disposed central axis, and a distal tip segment that lies along the central axis and terminates in an outlet orifice sized to support a probe therefrom, the shaft having a diameter substantially smaller than that of a blood vessel into which the shaft may be inserted so as not to substantially impede blood flow through the blood vessel, the tip segment being no greater in diameter than the shaft;

the inner and outer surfaces of the shaft and tip segment being substantially smooth;

the shaft including portions extending transversely from the central axis for engaging the inner luminal surface of the blood vessel at a plurality of circumferentially opposed points to support the distal tip segment at a distance from the inner luminal surface so that a probe passed from the outlet orifice remains in a spaced apart relationship from the inner luminal surface; and

a probe constructed to be passed through the catheter shaft without substantially distorting said transversely extending portions of the catheter shaft,

whereby the distal end of the probe may protrude beyond the distal outlet orifice substantially along the central axis.

28. A percutaneously insertable, needle mountable introducer catheter for guiding and supporting a probe within a blood vessel, and probe in combination, comprising:

a tubular elongate flexible catheter shaft having a proximal end and a distal end and having a predetermined cross-sectional radius;

the shaft having a fitting at its proximal end and a distal tip segment that terminates in an outlet orifice, the tip segment being no greater in diameter than the shaft;

the inner and outer surfaces of the catheter being substantially smooth;

the catheter having a longitudinally extending central axis that extends through the fitting and the outlet orifice;

a portion of the shaft extending between the fitting and the outlet orifice including portions that are spaced transversely from the central axis a distance greater than said predetermined radius thereby to enable said transversely spaced portions to engage the inner luminal surface of the blood vessel to stabilize the transverse position of the catheter within the blood vessel relative to the longitudinal axis of the blood vessel; and

the distal tip segment extending substantially along the central axis;

whereby the distal tip segment will be oriented so that a probe passed trough the catheter will emerge from the outlet orifice extending longitudinally of and substantially along the central axis; and

the probe constructed to be passed through the catheter shaft without substantially distorting said transversely extending portions of the catheter shaft,

whereby the distal end of the probe may protrude beyond the distal outlet orifice substantially along the central axis.