 |
Description  |
|
|
BACKGROUND OF THE INVENTION
This invention relates to new and useful improvements in self-sealing
gaskets within cannulas or percutaneous catheter introducers through which
tubes such as balloon catheters, electrodes, biopsy instruments,
closed-end cardiovascular catheters, etc. may be inserted and removed, and
in which the valve-gaskets maintain a seal at all times. Such devices are
used in medical procedures where it is often required to insert one tube
through another tube or into a housing or vessel while maintaining the
outer tube, housing or vessel sealed at all times.
Angiography is a noted and valuable procedure used to diagnose
cardiovascular disease. It involves the introduction of a hollow tubular
catheter into one of the major arteries or veins, such as the femoral or
brachial arteries, and advancing and maneuvering it into smaller branching
vessels which are to be studied. After the catheter is in position, a
radiopaque fluid is injected through the catheter into the desired area
and X-rays taken for diagnostic study.
Techniques for catheter introduction include "cut down" and other
modifications of the "Seldinger" technique. The "cut down" technique
involves surgically opening a vein or artery and introducing the
angiographic catheter directly through the incision.
30 American Journal of Cardiology, 378, (September, 1972), describes a
modification of the Seldinger technique, wherein a percutaneous sheath is
introduced into the lumen of a blood vessel. A hollow needle is inserted
through the skin and into the lumen, a guide wire is passed through the
needle and advanced up the artery or vein into the organ to be studied.
The needle is then removed, leaving the guide wire in the vessel. A sheath
and dilator unit are advanced over the wire into the vessel, and, the
dilator is removed along with the guide wire. Now, any type of catheter
desired of similar diameter, can be inserted through the sheath into the
vessel. To avoid excessive bleeding, and to reduce the possibility of an
air embolism, this technique and others require the physician to occlude
the orifice of the sheath during catheter changes.
These methods are characterized, especially if multiple studies are
indicated, by blood clots, blood loss, venous thrombosis, subcutaneous
hematomas, and other adverse conditions to patients.
PRIOR ART
Self-sealing cannulas or catheter introducers have been developed for these
procedures. These cannulas can be left in the vessel during angiographic
or other catheterization while the catheter is freely manipulated within
the cannula and vessel, with little or no blood loss. A seal capable of
withstanding the patient's blood pressure, when the catheter has been
removed, is also provided, thus obviating the necessity of occluding the
cannula and preventing significant blood loss at all times.
U.S. Pat. No. 4,000,739 to Stevens discloses a self-sealing gasket
arrangement in a catheter introducer that includes a pair of planar
slitted and apertured disc gaskets in face-to-face relation at the
proximal end of the cannula. The proximal disc has an annular opening and
the distal disc has a Y-slit.
U.S. Pat. No. 4,424,833 discloses a one piece self-sealing gasket molded
from a resilient latex rubber, having spaced sealing portions wherein the
proximal seal has an annular hole and the distal seal has a Y-slit, said
seals being spaced by the walls of the unit.
FIELD OF THE INVENTION
The present field is surgical percutaneous introduction of elongated
cylindrical devices such as hollow catheters, electrodes, biopsy
instruments, closed-end cardiovascular catheters, etc. into blood vessels
whereby leakage of blood is prevented through the introducer and
optionally providing a side port for blood sampling, infusion, pressure
monitoring or aspiration of fibrin deposits or other debris.
SUMMARY OF THE INVENTION
The present invention provides a self-sealing percutaneous tube introducer
having a pair of spaced flexible resilient gasket members and optionally a
side port. The proximal gasket has an annular opening at the distal and
sharp end of a conical projection and the distal seal has a Y-slit, with
sufficient space between so that passage distortion of a distally moving
tube will not cause the seals to touch (but they may touch on proximal
movement of the tube and resultant displacement of the distal seal).
Further objects, advantages and features of the introducer of this
invention will be apparent from the following more detailed description
and an illustrative embodiment of the invention shown in the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal cross section of an introducer embodying the
invention;
FIG. 2 is a partial cross section through the sealing elements, showing a
catheter being moved distally;
FIG. 3 is a similar partial cross section of the sealing elements showing
the catheter being moved proximally;
FIG. 4 is a perspective view of the Y-slit gasket, and
FIG. 5 shows a unit positioned within a patient.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The drawings show a main valve body 11 provided with a side port 12, a
female luer lock cap 13, a distal lock 14 and a strain relief tube 15
which is attached to the sheath 17. A tube 18 is attached to the side port
12 and leads to a connector or stopcock for infusion, e.g. heparin,
flushing, blood sampling, pressure monitoring, etc.
The female luer lock 13 permits easy attachment of items not shown, such as
a syringe for quick medication, or infusion, a corrugated sterile sleeve
to maintain sterility in the catheter while it is being introduced and
removed if desirable, etc.
FIG. 5 shows the unit with a catheter 19 inserted within a vessel lumen 21
through incision 22 of a patient's arm or leg 23, the catheter extending
proximally beyond the valve for attachment to a pressure dye source or for
manipulation by an operator, etc.
Within the passage flow chamber 24, there is positioned a gasket 26 having
a Y-slit 27 and flange 25, a spacer ring 28 and a spaced second gasket 29
provided with a hole 31 that terminates a conical portion 32 that points
toward the Y-slit gasket 26. At resting position or during tubular distal
movement, the gaskets do not touch. The Y-slit panels only touch the hole
gasket during movement of a catheter proximally as shown in FIG. 3. The
Y-slit gasket is of sufficient rigidity to maintain the planar position of
FIG. 1 against the patient's blood pressure when no catheter is present.
The conical construction of hole gasket 29 helps guide the catheter into
the appropriate position when being moved distally but more important,
causes little or no destruction or resistance to the movement of the
catheter, and particularly balloon catheters which must be handled with
care. On proximal movement of catheters (particularly large ones), the
conical portion 32 may invert into space 30 proximal to hole gasket 29.
The gaskets are made from silicone rubber or other flexible blood
compatible elastomers including natural and synthetic rubbers and pastics.
They should have a Shore A durometer of 30 to 80, preferably about 50-60
for the hole gasket and 60-70 for the Y-slit gasket. The spacer ring 28 is
metal or hard plastic.
Although Y-slit is preferable, it can be replaced with T, L, X, single
straight line, or other type slits.
These self-sealing units are intended to be disposable units, i.e.
discarded after a single procedure. However, in a single procedure, it is
common to insert and remove several devices, e.g. one catheter may be
replaced by another during the procedure, or at a minimum the spring guide
and dilator will probably be removed. Thus, the integrity of the seals
beyond one sliding tubular member is important.
It has been found that if two gaskets are positioned in abutting
relationship or even spaced as part of a single unitary construction, and
particularly without the conical arrangement of the hole gasket, the
removal of a catheter or other device may invert the entire gasket
relationship, which together with inadequate space allowance and/or
provision for retention, may result in damage or dislodging of the gaskets
or damage to the catheter. This conical design does not jam, permits
easier movement of catheter without stress thereon, and allows use of
greater variability in catheter sizes in the same unit, apparently because
of greater flexibility and possible inversion.
* * * * *
|
|
 |
|
 |
Description |
|
