 |
Description  |
|
|
SUMMARY OF THE INVENTION
The present invention relates to catheters and methods for fabricating such
catheters.
A various assortment of catheters has been proposed for use on patients,
such as endotracheal tubes and Foley catheters, in which the catheters
have an inflatable balloon secured onto the catheter shafts. During use of
the endotracheal tubes, the inflated balloons seal and retain the catheter
in the patient's trachea, while the balloons of Foley or urinary catheters
are inflated in the patient's bladder in order to retain the catheters in
place.
The catheter balloons are made from a flexible material which is normally
elastic, while the catheter shafts are preferably made from a more rigid
material to permit easy placement and provide greater structural integrity
of the shafts during use. Accordingly, in many cases it has become
desirable to make the balloons and shafts from different materials, such
as a silicone balloon for a non-silicone shaft, in order to achieve the
desired characteristics required by the catheter balloons and shafts. In
practice this has proven difficult to accomplish, since many of the
dissimilar materials are not susceptible to conventional bonding
techniques. Thus, the different materials frequently prove incompatible
when attempts are made to attach the balloon to the shaft through use of
heat sealing or known adhesives, and frequently a satisfactory bond cannot
be obtained between the balloon and shaft in a conventional manner.
SUMMARY OF THE INVENTION
A principal feature of the present invention is the provision of an
improved catheter and a method of fabricating the catheter in a simplified
manner.
According to a method of the present invention a flexible annular balloon
is secured on a shaft of the catheter by forming a pair of spaced annular
grooves in an outer surface of the shaft, positioning a first end portion
of the balloon intermediate a first shrinkable annular sleeve and one of
the grooves, and shrinking the first sleeve to secure the first end
portion of the balloon in the one groove. The remote end portion of the
balloon is positioned intermediate a second shrinkable annular sleeve and
the other of the grooves, and the second sleeve is shrunk to secure the
remote end portion of the balloon in the other groove.
Thus, a feature of the present invention is that the balloon is attached to
the shaft by shrinking the sleeves while securing end portions of the
balloon in the grooves of the shaft.
Another feature of the present invention is that the balloon is secured on
the shaft in a simplified manner.
Yet another feature of the invention is that the balloon may be secured to
the shaft while obtaining an excellent bond between the balloon and shaft
without the necessity of adhesives or sealing.
Still another feature of the invention is that the balloon may be readily
secured to the shaft in spite that the balloon and shaft may be made from
dissimilar materials which otherwise could not be bonded in a suitable
manner.
A further feature of the invention is the provision of a catheter having a
balloon secured to the catheter shaft in accordance with a method of the
present invention.
Further features will become more fully apparent in the following
description of the embodiments of this invention and from the appended
claims.
DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a fragmentary elevational view of a catheter of the present
invention;
FIG. 2 is a fragmentary sectional view of an elongated shaft of the
catheter of FIG. 1;
FIG. 3 is a perspective view of an annular sleeve utilized to secure an end
portion of a balloon to the catheter shaft;
FIGS. 4-6 are fragmentary elevational views, taken partly in section,
illustrating steps during securement of the balloon to the catheter shaft;
and
FIG. 7 is a fragmentary sectional view of the catheter illustrating the
balloon as secured to the shaft according to a method of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, there is shown a catheter generally designated 10
having an elongated shaft 12, an opening 14 adjacent a distal end 16 of
the shaft 12, and a balloon 18 of flexible material, such as silicone,
secured to the shaft 12 in accordance with a method of the present
invention. Although for convenience the catheter 10 is illustrated in the
form of an endotracheal tube, it will be apparent that the principles of
the present invention are equally applicable to other catheters, such as
Foley or urinary catheters.
With reference to FIG. 2, the catheter shaft 12 has a main lumen 20
extending through the shaft and communicating with the opening 14 at the
distal end 16 of the shaft 12. Also, the shaft 12 has an inflation lumen
22 in a wall 24 of the shaft 12 which communicates with an outer surface
26 of the shaft 12 through an aperture 28 in the wall 24. As shown, an
outer end 30 of the inflation lumen 22 is blocked by a suitable plug 32,
and the catheter 10 may have a tube or side arm 34 connected to the shaft
12 and defining an extension of the inflation lumen 22, such that fluid
may be passed through the tube 34 and inflation lumen 22 to control
inflation and deflation of the balloon 18 when secured to the shaft. The
shaft 12 also has a pair of spaced first and second annular grooves 36 and
38 defining recesses in the outer surface 26 of the catheter shaft 12.
With reference to FIG. 3, the securing means comprises an annular sleeve 40
of shrinkable material having a bore 42 extending through a wall 44 of the
sleeve 40. As will be seen below, first and second sleeves of similar
structure are utilized to secure the balloon onto the catheter shaft, and
for convenience the first and second sleeves will be designated by the
reference numerals 40a and 40b during the following description. The
sleeves 40a and b may be made of any suitable thermosetting or
thermoplastic heat shrinkable material, such as polyethylene or polyvinyl
chloride, in order that the sleeves shrink to a reduced size responsive to
heating.
With reference to FIG. 4, the balloon 18 comprises an elongated annular
sleeve of flexible material having a first end portion 46 defining a first
end edge 48 of the balloon 18, and a second opposed end portion 50
defining a second end edge 52 of the balloon 18. As shown, prior to
shrinking, the first sleeve 40a has an internal diameter greater than the
outer diameter of the catheter shaft 12, and, in accordance with a method
of the present invention, the first sleeve 40a is positioned over the
location of the first groove 36 of the shaft. The first end portion 46 of
the balloon 18 is positioned intermediate the first sleeve 40a and the
first groove 36 with the first end edge 48 of the balloon 18 being
directed toward the second groove 38, as shown.
Next, with reference to FIG. 5, the first sleeve 40a is subjected to a
shrinking procedure, such as heat shrinking, such that the dimensions of
the first sleeve 40a are significantly reduced and the first sleeve 40a
snugly engages the first end portion 46 of the balloon 18 in the first
groove 36. In this manner, the first end portion 46 of the balloon 18 is
secured in the annular first groove 36 of the catheter shaft 12 by the
shrunk sleeve 40a without the use of adhesives or heat sealing.
The remaining portion of the balloon 18 is then folded over the outer
surface of the first sleeve 40a. As illustrated in FIG. 6, the enlarged
second shrinkable sleeve 40b is positioned over the second groove 38, and
the remote second end portion 50 of the balloon 18 is folded to a location
intermediate the second sleeve 40b and second groove 83 with the second
end edge 52 of the balloon being directed toward the first groove 36. The
second sleeve 40b is then subjected to a shrinking treatment, such as heat
shrinking, in order to reduce the dimensions of the second sleeve 40b, as
shown in FIG. 7. As shown, the shrunk second sleeve 40b snugly engages
against the second end portion 50 of the balloon 18 and secures the second
end portion 50 of the balloon 18 in place intermediate the second sleeve
40b and the second groove 38.
Thus, the end portions 46 and 50 of the flexible balloon 18 are secured
beneath the respective sleeves 40a and 40b in a simplified manner without
the use of adhesives or sealing techniques. After fabrication, the first
end edge 48 of the first balloon end portion 46 is directed toward the
second groove 38 while the second end edge 52 of the second balloon end
portion 50 is directed toward the first groove 36. As shown, a central
portion 54 of the balloon extends over the outer surface 26 of the
catheter shaft 12 with side portions 56a and 56b overlying outer surfaces
of the respective shrunk first and second sleeves 40a and b. With
reference to FIGS. 1 and 7, the balloon may be inflated at the time of use
by passage of fluid through the tube 34, through the inflation lumen 22,
and the wall aperture 28 into a cavity 58 defined intermediate the central
portion 54 of the balloon 18 and the outer surface 26 of the catheter
shaft 12. The balloon 18 may be deflated by reverse passage of fluid from
the cavity 58 through the inflation lumen 22 and the tube 34.
The foregoing detailed description is given for clearness of understanding
only, and no unnecessary limitations should be understood therefrom, as
modifications will be obvious to those skilled in the art.
* * * * *
|
|
 |
|
 |
Description |
|
