Note: Descriptions are shown in the official language in which they were submitted.
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STYLET FOR CONTROLLED DEFORMATION OF A TUBE
This application claims the benefit of U.S. Provisional Application
Serial No. 60/003.680 tiled on September 1 l, 1995.
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to a hollow tube and, more particularly, to a
stylet which can be manipulated to deflect the tube in which the stylet is
received. In another aspect. this invention relates to a method for inserting
a
tube into a patient's stomach through the nose or mouth.
Description of the Related Art
Hollow tubes have numerous applications in the medical field. For
example, hollow tubes can be inserted through a patient's nose or mouth and be
received in the stomach for either removing fluid and material therefrom or
providing food or nutrients to a patient. In another application of tube and
stylet assemblies, a tube can be inserted into a patient's nose or mouth and
received into the tracheal opening for providing oxygen to a patient's lungs.
Numerous other applications of tubes exist.
One signif cant problem in properly inserting a tube into a patient
for the applications described above is controlling the tube during the
insertion
process. The nasal and oral passageways have significant contours making it
difficult to properly insert the tube without causing undue trauma to the
tissue
of the passageway. Attempts at controlling this deformation of the tube are
seen
in U.S. Patent No. 5,259.377 to Schroeder; U.S. Patent No. 4,180,076 to
Betancourt; U.S. Patent Nos. 5,195.968 and 5,336,182 to Lundquist et al.; U.S.
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Patent No. x,358,478 to Thompson et al.; and U.S. Patent No. ?,574,840 to
Pieri
et al. The prior art attempts have failed to create a stylet which can be
controlled in multiple directions and which is simple and easy to manufacture
and operate.
SUMMARY OF THE INVENTION
A stylet and tube assembly particularly useful for inserting a
gastric tube either nasally or orally is shown. The stylet and tube assembly
comprises a tube having a proximal end, a distal end and a body intermediate
the proximal and distal ends. A lumen extends through the tube and a stylet is
telescopically received therein. The stylet comprises a first filament having
a
proximal end, a distal end and a body portion intermediate the proximal and
distal ends. The stylet also includes a second filament having a proximal end,
a
distal end and a body portion intermediate the proximal and distal ends. The
ends of the second filament are joined to the first filament such that the
longitudinal axes of the first and second filaments define a plane. With this
structure, deflection of the stylet in a first direction, substantially along
the
plane results in a corresponding, opposite second deflection of the stylet
along
the plane. With this structure, a user can manipulate a tube and stylet to
match
the convoluted contour of a passageway in which the tube and stylet are being
inserted, such as the nasal or oral passageway to the stomach.
In a preferred embodiment, the first and second filaments each
have a substantially flat surface extending longitudinally along a portion of
the
length thereof. The filaments are joined to one another such that the first
and
second filaments abut one another. The flat surfaces are adapted to slide
along
one another as the stylet is deflected along the plane of curvature.
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Preferably, the first and second filaments are D-shaped in cross
section and the second filament is joined to the first filament by a process
such
as heat staking, welding, or adhesive. Alternatively, the stvlet can be
injection
molded or extruded and then slit along a portion of the length thereof to
create
the first and second filaments therefrom. Other suitable cross sectional
shapes
include rectangular, square, triangular, oval, circular and slotted.
In another aspect, the invention comprises a method for nasally or
orally inserting a tube into a patient's stomach. The method begins by
providing a tube and stylet as described above. The distal end of the tube and
stylet are inserted into either the patient's nose or mouth. Next, a portion
of the
stylet which remains outside of the patient's nose or mouth is deflected to
create
a radius of curvature which lies substantially along the plane of curvature.
This
necessarily results in a corresponding, opposite deflection of the stylet and
tube
which are received inside the patient's nasal or oral passageway. The portion
of
the tube and stylet outside of the patient are deflected according to the
anatomical curvature of the patient's oral or nasal passageway thereby
permitting easier insertion. The tube is ultimately received in the patient's
stomach and the stylet is removed therefrom such that the tube may be used for
removing fluid and material therefrom or providing fluid thereto.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the
drawings in which:
FIG. 1 is a perspective view of a stylet and tube assembly
according to the invention;
FIG. 2 is a side elevational view of a portion of a stylet according
to the invention with the tube shown in phantom lines;
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FIG. 3 is a cross-sectional view of the stylet and tube assembly
taken along lines 3-3 of FIG. 1;
FIG. 4 is a side elevational view the stylet and tube assembly
deformed in a first direction:
FIG. 5 is a side elevational view of the stylet and tube assembly
deformed in a second direction;
FIG. 6 is a partial sectional view of the initial stages of inserting
a gastric tube nasally;
FIG. 7 is a partial sectional view of an interim step of the nasal
insertion of a gastric tube utilizing a stylet according to the invention;
FIG. 8 is a partial sectional view of the latter stages of the nasal
insertion of a gastric tube utilizing a stylet according to the invention;
FIG. 9 is a partial sectional view of the interim stage of the oral
insertion of a gastric tube utilizing a stylet according to the invention;
FIG. 10 is a flow chart of one embodiment of a method for nasally
inserting a gastric tube utilizing a stylet according to the invention; and
FIGS. 11-16 show different cross sectional shapes for alternative
embodiments of the filaments similar to that seen in FIG. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings and to FIG's 1-5 in detail, a tube
and stylet assembly 12 according to the invention is shown. The assembly 12
comprises a pliable tube 14 having a deformable stylet 16 telescopically
received therein. The tube 14 comprises a proximal end 20, a distal end 22 and
a body 24 intermediate the proximal and distal ends. A conventional luer
fitting
26 is provided on the proximal end 20 and is mounted to suitable machinery
such as a suction apparatus or a fluid injection apparatus (not shown)
depending
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upon the application of tube 14. A primary lumen 28 extends from the
proximal end 20 to the distal end 22 of the tube 14. The preferred embodiment
of the tube 14 further comprises a secondary lumen 30 which similarly extends
from the proximal end 20 to the distal end 22. 'The secondary lumen 30 is
integrally formed in the tube 14 such that the proximal end of the lumen 30
terminates at a fluid conduit 32 extending outwardly from the tube 14 through
a
suitable aperture. The fluid conduit 32 has a conventional fitting (not shown)
mounted thereon for connecting the secondary lumen 30 to a source of suction,
pressurized fluid or other apparatus. depending upon the application of the
tube
14. The secondary lumen 30 is often included in conventional gastric tubes.
However, this element is by no means a requirement of the invention and a tube
having a single lumen certainly falls within the scope of the invention.
The distal end 22 of the tube 14 terminates in a rounded tip 38
which closes the end of the primary lumen 28. A plurality of apertures 40 are
formed in the distal end 22 of the tube 14 provide fluid communication between
the primary lumen 28, secondary lumen 30 and the exterior of the tube 14. The
structure of the preferred embodiment of the tube described above is
commercially available from Sherwood Medical Co. of St. Louis, MO and is
sold under the trademark Salem Sump TubeTM.
The stylet 16 comprises a first filament 42 and a second filament
44 which are joined to one another. The first filament comprises a proximal
end 46, a distal end 48 and a body 50 intermediate the proximal and distal
ends.
Similarly, the second filament 44 comprises a proximal end 62, distal end 64
and body 66 intermediate to the proximal and distal ends. Preferably, the
first
and second filaments 42, 44 are substantially rectangular in cross section
wherein the first filament 42 has a top surface 52, a bottom surface 54 and a
pair of opposed side surfaces 56, 58, and the second filament has a top
surface
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68, bottom surface 70 and a pair of opposed side surfaces 72. 74. As seen in
FIG. 3, the first and second filaments 42. 44 are dimensioned such that the
bottom surface ~4 of the first filament 42 abuts the top surface 68 of the
second
filament 44 and the top and side walls ~2, 56, 58 of the first filament 42 and
bottom and side walls 70, 72, 74 of the second filament 44 are closely
adjacent
to the interior surface 34 of the primary Lumen 28.
The Length of the stylet 16 where the second filament 44 is
mounted to the first filament is known as the active portion 76 and the
remainder of the stylet is the static portion 78.
The proximal and distal ends 62, 64 of the second filament 44 are
joined to the first filament 42 such that the bottom surface 54 of the first
filament 42 is closely adjacent to the top surface 68 of the second filament
44.
Preferably, the first and second filaments are formed from a plastic - type
material such as acetal or nylon. However, any flexible, durable material will
be suitable.
If the filaments are formed from nylon, or some other
thermoplastic material then the proximal and distal ends 62, 64 of the second
filament 44 may be joined to the first filament 42 by a suitable process such
as
heat staking, ultrasonic welding or adhesive. Alternatively, the filaments
could
be extruded or injection molded and then partially slit along the length
thereof
to create the first and second filaments and the joined proximal and distal
ends
of the second filament.
As seen in FIGS. 4 and 5, the tube 14 is selectively deformable by
manipulation of the active portion 76 of the styiet 16 inside the tube 14. The
stylet 16 is adapted to permit controlled deformation of one portion of the
stylet
16 and tube i 4 in response to manipulation of a second portion of the stylet
16
and tube 14. In other words, deformation of the stylet 16 and tube 14 adjacent
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to the proximal end 62 of the second filament 44 will result in a
corresponding
opposite deformation of the stylet 16 and tube 14 adjacent the distal end 64
of
the second filament 44. This cause and effect action is the result of the
joined
structure of the first and second filaments 42, 44. As noted above, the bottom
surface 54 of the first filament 42 preferably abuts the top surface 68 of the
second filament 44 when the stylet 16 is in a relaxed position and the
proximate
and distal ends 62, 64 of the second filament 44 are joined to the first
filament
42. Therefore, bending of the second filament 44 when the f rst and second
filaments are received inside the tube 14 results in corresponding bending of
the
first filament 42. If opposed forces are applied to the tube 14 and stylet 16
in a
direction substantially normal to the abutting bottom and top surfaces 54, 68
of
the first and second filaments 42, 44 respectively, then these forces will
cause a
corresponding deformation of the stylet 16 and tube 14 about a first radius
having a prescribed centerpoint. The forces are identified by force vectors A
and B in FIGS. 4 and 5. As the first filament 42 is bent about a radius
centered
at the force vector A, then the second filament 44 must similarly deflect
because
the ends of the second filament are joined to the first filament. However, the
thickness of the two abutting filaments prevents the second filament 44 from
rotating about the same radius and centerpoint as the deflection of the first
filament 42. In fact, the second filament rotates about a second radius having
a
second centerpoint. Deflection of the first and second filaments, which are
joined together, about two different radii of curvature will necessarily
result in a
second deformation of the first and second filaments about two different radii
of
curvature. The second deformation is opposite to the first deformation and
compensates for the differing radii of curvature of the joined first and
second
filaments 42, 44.
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As seen in FIG. 4. the stylet is deflected by the application of
forces in the direction of force vectors A and B. The deflection of the first
filament 42 about a first radius of curvature at force vector A results in a
second
radius of curvature of the second filament 44 at the force vector A. The
corresponding, opposed deflection of the first and second filaments 42, 44
occurs at arrow C.
The second filament 44 has assumed a radius of curvature at arrow
C which is substantially identical to the f rst radius of curvature of the
first
filament 42 at force vector A. Similarly, the first filament 42 has assumed a
radius of curvature at arrow C which is substantially identical in vector, but
opposed in direction to the second radius of curvature of the second filament
44
at force vector A. The difference in the radii of curvature between the first
and
second f laments at the arrows A and C is based primarily on the thickness of
the filaments. Varying the thickness of one or both of the filaments will
result
in a corresponding alteration of the radii of curvature as the filaments are
deformed with respect to one another along a plane which is substantially
perpendicular to the abutting surfaces of the two filaments.
FIG. 4 shows deflection of the first and second filaments in a first
direction along a plane substantially perpendicular to the abutting surfaces
of the
first and second filaments. FIG. S shows a similar deflection of the first and
second filaments in a second direction along the plane substantially
perpendicular to the abutting surfaces of the first and second filaments.
The structure of the filaments 42, 44 according to the invention
permits controlled deflection of the distal portion of the tube and stylet
through
manipulation of a portion of the tube 14 proximal of the point of desired
deflection. The location of the second, opposed deflection along the length of
the active portion of the stylet 16 can also be controlled. Generally, the
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centerpoint of the second, opposed deflection will be spaced from the joined,
distal ends of the first and second filaments 42. 44 a distance which is equal
to
the spacing of the first deflection from the joined proximal ends of the first
and
second filaments 42, 44. Therefore, if the user wants to create deflection of
the
stylet immediately adjacent to the distal tip, then the user will create the
deflection of the stylet I6 immediately adjacent to the proximal ends.
Similarly,
if the user wants to create a broader arc across the distal portion of the
stylet I6,
then the user will manipulate the proximal portion of the stylet 16 a greater
spaced distance from the joined proximal ends.
In the preferred embodiment, the deflection of the distal end of the
stylet 16 is manipulated through the deflection of the proximal end of the
second filament 44 and first filament 42. This particular orientation is the
preferred embodiment of the stylet. However, it is within the scope of the
invention to manipulate the distal portions of the stylets to impose
deflection of
a portion of the stylet proximally thereof.
The ability to control deformation of the distal end of the tube and
stylet assembly through manipulation of a portion of the tube and stylet
spaced
proximately from the distal end provides several significant advantages when
inserting tubes into a contoured orifice. For example, one significant
application of the stylet according to the invention is manipulating a gastric
tube
as it is being inserted either nasally or orally. FIGS. 6-8 show several steps
of
inserting a gastric tube nasally. FIG. 10 is a flow chart of the method of
nasally
or orally inserting the tube and stylet assembly 12 according to the
invention.
As is evident from the sectional views of the patient's anatomy,
5 the tube and stylet assembly 12 must be deflected and manipulated
significantly
along a plane extending substantially parallel to the longitudinal axis of the
patient's neck. Therefore, the stylet 16 is mounted in the tube 14 such that
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plane of the adjoining first and second filaments 42. 44 is substantially
perpendicular to the direction of deformation required of the tube and stylet
assembly 12. As seen in FIG. 6, the nasal insertion process begins by
inserting
the rounded tip 38 of the tube 14 into the patient's nasal opening 80.
Initially,
S the tube 14 and stylet 16 are initially inserted in a substantially straight
configuration. The distal end 22 of the tube 14 is inserted into the nasal
cavity
82 in a substantially linear configuration until the rounded tip 38 approaches
the
rear of the nasal cavity 82. Once this interim step is reached, the portion of
the
tube and stylet assembly 14 remaining outside of the patient is manipulated to
cause a deformation of the distal ends of the filaments and tube 14
corresponding to the patient's anatomy.
As seen in FIG. 7, the outboard portion of the tube and stylet
assembly 12 is deflected about the axis of rotation identified by force vector
A
in response to a force being applied in the direction of force vector B. This
deflection of the first filament and proximal portion of the second filament
44
necessarily results in a corresponding, opposed deflection of the distal
portions
of the tube 14 and the styiet 16 received therein. The proximal portion of the
stylet 16 adjacent the nasal opening 80 is deflected about the axis of
curvature
A. This causes the rounded tip 38 of the tube 14 to deflect upwardly as seen
in
FIG. 7 into the pharynx 82. The deformation of the distal end 22 of the tube
14
as seen in FIG. 7 is most easily accomplished by the user placing her thumb at
the point identified by force vector A and then pivoting the proximal portion
of
the tube and stylet assembly 12 about her thumb, thereby resulting in
deflection
of the distal end 22 of the tube.
2S With the rounded tip 38 of the tube 14 deflected toward the
pharynx 84, the tube 14 can be inserted further into the patient's nasal
opening
80 until the rounded tip 38 approaches the esophagus 86 and trachea 88.
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As seen in FIG. 8, the contour of the nasal passageway will, out of
necessity, deflect the rounded tip 38 of the tube 14 downwardly such that the
tube 14, upon further insertion, is received in the esophagus 86, as desired,
rather than the trachea 88. Due to the contour of the patient's nasal cavity
82
and pharynx 84, the proximal portion of the active portion 76 of the stylet
will
be deflected around a radius of curvature A. This will necessarily force the
distal portion 22 of the tube downwardly, thereby contacting the rear surface
of
the patient's pharynx 84. In this position, the tube and stylet assembly 12
can
be inserted further until the distal end 22 of the tube 14 is received in the
esophagus 86. Once the distal end 22 is past the pharynx 84 and the rounded
tip 58 is in the esophagus 86, the stylet assembly 12 returns to the relaxed
position allowing the tube 14 to enter the stomach. Once the tube 14 is
properly placed into the patient's stomach, then the stylet 16 can be removed
and suitable suction or feeding machinery can be attached to the luer fitting
26
of the tube 14.
In the preferred embodiment, the length of the second filament 44
is dimensioned such that the entire length of the second filament 44 is
received
inside the patient as the distal end 22 of the tube 14 approaches the opening
of
the esophagus 86. However, it is to be understood that the second filament 44
can be dimensioned to any length, depending upon the particular application.
For example, it may be desired to extend the length of the second filament 44
such that a portion of the second filament 44 remains outside of the patient
as
the distal end 22 approaches the esophagus 86 such that the user can control
deflection of the distal end 22 through hand manipulation of the first and
second
filaments.
The preferred embodiment of the tube and stylet assembly 12 is
nasally inserted into the patient's stomach. However, as seen in FIG. 9, the
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tube and stylet assembly may also be inserted through the patient's mouth
opening 90. Similar to the nasal insertion process. the stylet 16 is received
in
the tube 14 such that the proximal end of the first and second filaments 42,
44
are adjacent the rounded tip 34 of the tube 14. 'Then, the distal end 22 of
the
tube 14 is inserted into the patient's mouth opening 90 and inserted
rearwardly
into the patient's mouth. As the rounded tip 38 approaches the rear wall of
the
patient's pharynx 84, the proximal portion of the second filament 44 and the
first filament 42 is deflected toward the patient's forehead according to
force
vectors A and B to generate the desired upward, deflection of the rounded tip
38. This deflection causes the distal end 22 of the tube 14 to deflect toward
the
opening of the esophagus 86. Through the controlled deflection of the rounded
tip, the tube 14 can be manipulated to follow the patient's anatomy without
forcing the tube 14 and stylet down the patient's oral and nasal passageways
thereby reducing trauma to the tissue of the patient's oral and nasal
passageway.
Similar to the process described above, as the rounded tip 38
approaches the opening of the esophagus 86, the proximal portion of the second
filament 44 and first filament 42 can be manipulated to guide the rounded tip
38
into the patient's esophagus 86. As described above, the tube 14 and stylet I6
can be further inserted into the patient's stomach for application of the
tube.
The stylet 16 can be removed from the tube once the tube is properly
positioned
in the esophagus 86. Alternatively, the stylet I6 can be removed after the
tube
14 is properly positioned in the patient's stomach.
Through the use of the stylet 16 according to the invention, a tube
14 can be guided through a contoured passageway through simple manipulation
of the tube and stylet. With this structure, a user can now control the
deflection
of the tube and more easily insert the tube into a patient while reducing
trauma
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to the patient during the insertion process. All of this is accomplished with
an
inexpensive and easily manufactured stylet.
FIGS. 11-16 show alternative embodiments of the filament cross
sectional shape. In FIG. 11, the preferred cross sectional shape of the
filaments
42, 44 is shown namely, D-shaped. In FIG. 12, the filaments 142, 144 are
triangular in cross section. FIG. 13 shows filaments 242, 244 which are
rectangular in cross section and in FIG. 14, the filaments 342, 344 include a
groove 346 and projection 348 on the abutting faces to ensure proper sliding
movement of the filaments 342, 344 with respect to one another. In FIG. 1 S,
the filaments 442, 444 are circular in cross section and in FIG. 16, the
filaments
542, 544 are square or diamond-shaped and oriented such that the pointed
corners 546, 548 of the two filaments 542, 544 abut one another.
In an alternative embodiment, one of the effective lengths of the
two filaments 42, 44 could be longer than the other, thereby inducing a pre-
bend into the stylet. With this structure, the effective length can still be
manipulated to create a desired bend by deflecting the overlapping filaments.
Reasonable variation and modification are possible within the spirit
of the foregoing specification and drawings without departing from the scope
of
the invention.
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