CA2087335C

CA2087335C - Enteral feeding tube

Info

Publication number: CA2087335C
Application number: CA002087335A
Authority: CA
Inventors: Eugene Francis Schrader; Eugene Elmer Weilbacher; Raymond Otto Bodicky; James Gerard Schneider
Original assignee: Sherwood Medical Co
Current assignee: Sherwood Medical Co
Priority date: 1990-07-19
Filing date: 1991-07-16
Publication date: 1997-09-16
Anticipated expiration: 2011-07-16
Also published as: EP0591192A1; AU656143B2; AU8308491A; WO1992001436A1; CA2087335A1

Abstract

A relatively flexible, dual-lumen enteral feeding tube (10) for delivery of fluid through a patient's esophagus to the patient's intestinal tract is provided having an enteral feeding lumen (22) and a relatively small stylet lumen (24) separate from the enteral feeding lumen (22) and longitudinally co-extensive with a substantial length of the enteral feeding lumen (22). The stylet lumen (24) has a removable relatively stiff metal stylet (85), the stylet (85) with a tapered annealed distal portion. The stylet (85) has a coating of polytetrafluorethylene and a coating of silicone over the polytetrafluorethylene. The tube (10) also has a Y-site adaptor (16) fixed on the proximal end of the tube (10). The Y-site adaptor (16) has Y-site openings through which access may be had to the enteral feeding lumen (22).

Description

W O 92/01436 PC~r/US91/04848 , IMPROVED ENTERAL FEEDING TUBE

TECHNICAL FIELD
The present invention relates to an improved enteral feeding tube for delivering nutritional, irrigational, or medicinal fluids or the like to the intestinal tract of a patient.

BACKGROUND ART
Enteral feeding tubes are conventionally used for introducing nutritional, irrigational, or medicinal fluids, or all of these, through a patient's mouth or nose and esophagus into the patient's intestinal tract and sometimes for aspiration of fluids therefrom. Such enteral feeding tubes are typically constructed of soft, flexible material to minimize patient discomfort and trauma during insertion lS and extended placement. Because these tubes are convention-ally constructed of soft, flexible material, such as poly-urethane or the like, a relatively stiff but narrow metal stylet is conventionally inserted into a relatively large feeding lumen of the tube to stiffen the same to facilitate forcing the tube through the restricted, tortuous path required for movement through the patient's mouth or nose and esophagus for insertion into the patient's stomach or intestines. Such a stylet placement is disclosed in the U.S. Patent Nos. 4,659,328 to Potter et al and 4,874,365 to Frederick et al.
Proper placement of the feeding tube in the intestinal tract of the patient is sometimes difficult to achieve and is usually ascertained by x-ray, aspiration of gastric con-tents, auscultation by stethoscope placed over the stomach during air injection or other checking method. If placement appears to be appropriate, the wire stylet is then removed for patient comfort. However, for a number of reasons including improper placement or accidental dislodgement, it W O 92/01436 PC~r/US91/04848 - ~ ~0~7335 2 is sometimes necessary to reinsert the stylet into the feeding tube to alter the location thereof. Utilizing conventional enteral feeding tubes and stylets, removal, insertion and reinsertion of such stylet or reinsertion of a new stylet often proves to be difficult and even dangerous.
This is because of insufficient or excessive stylet stiff-ness, friction between the tube lumen and the stylet, and the danger of the stylet piercing the tube lumen or protrud-ing through the distal opening of the feeding tube, thereby exposing the stylet and possibly causing injury to the patient. Additionally, re-handling of the stylet after con-tamination thereof in the feeding lumen of a conventional enteral feeding tube by the patient's bodily fluids is some-times considered undesirable or disconcerting to health care workers.

DISCLOSURE OF INVENTION
In this light, it is a general object of the present invention to circumvent or solve the problems noted above.
In achieving this general object, the present invention provides a relatively flexible, dual-lumen enteral feeding tube for delivering fluids through a patient's esophagus to - the patient's intestinal tract, the enteral feeding tube having proximal and distal ends and comprising a primary or enteral feeding lumen having a feeding lumen inlet opening adjacent the proximal end of the tube and at least one feeding lumen outlet opening adjacent the distal end of the tube. A secondary or stylet lumen separate from the enteral feeding lumen is additionally provided, the stylet lumen having a stylet lumen opening adjacent the proximal end of the tube and being longitudinally co-extensive with a sub-stantial length of the enteral feeding lumen and clo~ed on its distal end. According to the present invention, a relatively stiff wire stylet is removably positioned in the stylet lumen and extends from the stylet lumen opening to adjacent the feeding lumen outlet opening. Because the wire stylet is positioned in a separate stylet lumen instead of in the enteral feeding lumen, it cannot interfere with fluid flow and the stylet is not contaminated by bodily fluids, as would be the case if the wire stylet were positioned in the enteral feeding lumen as in some prior art devices. Addi-tionally, because the stylet lumen is substantially smaller than the enteral feeding lumen and the stylet is more close-ly confined therein, in some circumstances this arrangement assists in stiffening the enteral feeding tube to a more appropriate degree than would be the case if the stylet were loosely positioned in the substantially larger enteral feeding lumen.
The stylet has a relatively enlarged globe on the distal end thereof, 5 the globe having a diameter slightly less than the diameter of the stylet lumen. The stylet has a coating of TEFLON~' polymer (polytetrafluorethylene), over which a lubricous coating of silicone is applied. It is believed that such a lubricous coating arrangement facilitates insertion and withdrawal of the stylet to or from the relatively small diameter stylet lumen by reducing the drag of the stylet against the interior of the stylet lumen compared to the drag presented in an arrangement where the silicone is applied directly to the wire stylet for lubrica-tion purposes. Additionally, because the silicone coated stylet is positioned in another lumen separate from the feeding lumen, the silicone is not contaminated by bodily fluids possibly present in the main or enteral feeding lumen.
These and other objects and advantages of the present invention will become apparent from the following detailed description of the present invention when read in conjunc-tion with the accompanying drawings, described as follows.
B

208~ 33S 4 BRIEF DESCRIPTION OF DRAWINGS
Figure 1 is a plan view of an improved enteral feeding tube according to the present invention, with portions thereof broken away for illustrative purposes;
Figure 2 is a cross-sectional view of the enteral feeding tube shown in Figure 1 and taken along lines 2-2 therein;
Figure 3 is a left side view of the enteral feeding tube shown in Figure l; and Figure 4 is plan view, on an enlarged scale, of a distal tip portion of a wire stylet of the enteral feeding tube shown in Figure l; and Figure 5 is a schematic illustration on an enlarged scale of the distal tip portion of the wire stylet shown in Figure 4 but shown with TEFLONX and silicone coatings sche-matically represented on the stylet according to the present invention .

MODES FOR CARRYING OUT THE INVENTION
Referring in more detail to Figure 1 of the drawings, there is illustrated therein an improved enteral feeding tube 10 for nasogastric or nasointestinal feeding which basically comprises a relatively flexible, dual-lumen tube assembly 12, to the distal end of which is fixed a conven-tional bolus weight assembly 14. Fixed to the proximal end of the tube assembly 12 is a Y-site connector, adaptor and closure assembly 16, to the right of which, as shown in Figure 1, is fixedly positioned a laterally projecting stylet opening saddle 18 having a wire stylet assembly 20 removably positioned therein.
The dual-lumen tube assembly 12 is constructed of a soft, flexible material, such as polyurethane or the like, in relatively small diameters, such as from 8 to 12 French (0.1048 to 0.1572 inch) (.2662 cm to .3993 cm). As best seen in Figure 2, the tube assembly 12 is hollow and com-. . ~

prises a relatively large diameter primary or enteral feed-ing lumen 22 adjacent a relatively small diameter, separate secondary or stylet lumen 24, approximately 0.04 inch (.10 cm) in diameter the distal end 26 of which is closed as by dead-ending within the tube assembly 12 by a plug or the like. The proximal end 28 of the stylet lumen is in commu-nication with an angularly oriented saddle lumen 30 of a like small diameter extending from the proximal end 28 of the stylet lumen to a stylet lumen inlet opening or port 31 provided in a laterally offset face 33 in the stylet opening saddle 18.
The enteral feeding lumen 22 extends from its proximal end 32 to its distal end 34 adjacent a bolus weight assembly junction 36 fixed between the tube assembly 12 and the bolus weight assembly 14 and through which are provided two longi-tudinally-spaced enteral feeding lumen outlets 38 and 40 spaced at 180~ about the tube periphery in fluid communica-tion with the distal end 34 of the enteral feeding lumen 22.
The exterior surface of the tube assembly 12 is provided with a plurality of depth gauge or reference marks 41 to assist in properly positioning the enteral feeding tube 10.
The bolus weight assembly 14 includes a cavity 42 in which are positioned a plurality of conventional cylindrical bolus weights 44 constructed of tungsten and of approximate-ly 0.75 gram each, the function of which is to assist inpositioning the enteral feeding tube in the patient's diges-tive system and maintaining such positioning over an extended period. A radiopaque line 46 may be provided on the surface of the bolus weight assembly 14 to assist in locating the position of the distal end 48 of the enteral feeding tube 10 in a patient by conventional x-ray means or this line 46 may be eliminated because the weights 44 are by their nature radiopaque and therefore make the line 46 unnecessary. Alternately, the tube assembly 12 and bolus weight assembly 14 may be constructed of a plastic material . ' ;;
2~ 3~S

such as DOW PELLETHANE~ thermoplastic with Barium Sulfate (BaSO4) mixed throughout such material to provide a radi-opaque construction of the entire tube and bolus assemblies.
The distal end 48 of the bolus weight assembly 14 is provided with a cushion of soft, flexible material such as polyurethane, and is rounded to avoid trauma to the patient induced by tube insertion or extended placement.
Referring to Figures 1 and 3 of the drawings, the Y-site connector, adaptor and closure assembly 16 is con-structed of a plastic material such as polyvinyl chloride,or the like and is fixed.to the proximal end of the tube assembly 12. The Y-site connector comprises a hollow feed-ing tube portion 50 including a feeding port lumen 52 in fluid communication with the proximal end 32 of the enteral feeding lumen 22 and an angularly disposed, hollow irriga-tion tube portion 54 including an irrigation port or lumen 56, the distal end of which is in fluid communication with the distal end of the feeding port lumen 52 and thereby in fluid communication with the proximal end 32 of the enteral feeding lumen 22. The feeding port lumen 52 and irrigation port lumen 56 include larger and adjacent smaller diameter portions which are shaped, sized and adapted to receive a conventional catheter tip syringe and the feeding port lumen is also shaped and sized to receive a standard stepped feeding tube connector of a conventional enteral administra-tion tubing set. The irrigation port lumen 56 is also adapted to receive an adaptor, as will be hereinafter dis-cussed, to facilitate reception of a conventional luer tip syringe, and is adapted to be used for delivery of any irrigational, medicinal, or other prescribed fluids to the patient's intestinal tract or aspiration of fluids there-from.
Connected to the proximal end of the feeding tube portion 50 by a flexible arm 58 is a cup-shaped closure 60, as best seen in Figure 3, the closed end 62 of which is W O 92/01436 PC~r/US91/04X4X

~08~73 3~

adapted to be inserted in the feeding port or lumen 52 with the cup-shaped recess 64 on the exterior side of the closure 60 when seated in the feeding port or lumen 52. It should be noted that by providing the cup-shaped recess 64 on the exterior side of the closure 60, the closure 60 may be conveniently compressed for insertion into the feeding port lumen 52 and withdrawal therefrom. But further, this clo-sure arrangement is considered to be advantageous over prior art closures for feeding lumen wherein the closure is re-lo versed and the cup-shaped recess side of the closure is inserted into a feeding port lumen because when such a reversed closure is removed, the recess sometimes carry a significant amount of patient bodily fluid contaminants accumulated in the recess by virtue of fluid communication of the recess with the interior of a feeding port lumen, and thereby exposing a health care worker to contact with such contaminants. The distal end of flexible arm 58 further includes a web 66 extending beyond the closure 60, the web being provided with a finger-grip projection 68 to facili-tate insertion and withdrawal of the closure 60 in or fromthe feeding port lumen 52.
Connected to the proximal end of the irrigation tube portion 54 is a flexible arm 70 and a hollow tubular adaptor 72, having a bore 73 therein, the adaptor being shaped and sized to be positioned in the irrigation port lumen 56 to reduce the size thereof to facilitate sealing engagement with a luer slip or luer lock tip of a syringe. Connected to the arm 70 and the adaptor 72 is a web 74 having a finger-grip projection 76 to facilitate insertion and with-drawal of the adaptor 72 in or from the irrigation portlumen 56. Connected to the outer end of the web 74 is a second flexible arm 78, as shown in Figure 1, which is connected to a solid cylindrical closure or plug 80, shaped and sized for insertion into and sealing engagement with the bore 73 of the hollow tubular adaptor 72. The plug 80 is ~o8'133~
. i 8 supported on a web 82, the outer end of which is provided with a finger-grip projection 84 to facilitate insertion or withdrawal of the plug 80 from the bore 73 of the hollow tubular adaptor 72.
Referring to Figures 1 and 4 of the drawings, the wire stylet assembly 20 comprises a stainless steel wire 85 of appropriate strength (290,000 to 300,000 P.S.I. tensile strength) (20,407 K9/cm2 to 21,111 K9/cm2) and rigidity to appropriately stiffen the enteral feeding tube 10 for inser-tion through the nose or mouth, the esophagus and into the stomach or small intestines. The wire 85 is fully hardened along the full length thereof except adjacent the distal end thereof which will be subsequently discussed.
The proximal free end of the wire 85 is looped back on itself to form a finger pull or wire loop 86 by fixing the free end to the shaft 88 of the wire 85 by positioning the free end and the adjacent portion of the shaft 88 in an appropriately sized section of heat shrink tubing 89 having an adhesive-coating on the inner surface thereof and heating the same to shrink the tubing 89 and thereby fix the free end to the shaft 88. Such heat shrink tubing may be like FIT~ 321 shrinkable polyolefin tubing sold by Alpha Wire Corporation, or equivalent.
The wire loop 86 is positioned on the proximal exterior side of the stylet opening saddle 18 when the stylet is in-serted in the stylet lumen inlet opening 30 and bottomed in the stylet lumen 24. It should be noted that the stylet opening saddle is longitudinally spaced and laterally offset from the Y-site connector for convenience on stylet inser-tion. Additionally, this positioning, as opposed to alocation in the Y-site connector, avoids obstructing or interference with use of the Y-site or primary lumen for other, more usual, purposes.
The distal end 90 of the wire 85, as shown in Figure 4, is tapered in a converging manner commencing at a point -208733~

about three inches (7.62 cm) from the distal end to enhance the flexibility thereof to meet the requirement of the tortuous path of tube insertion and is fixedly connected at its distal end, as by plasma welding, to a spherical stylet globe 92. The diameter of the wire shaft 88 at point "A" as indicated in Figure 4, is about 0.02 inch (.05 cm), at point "B" is about 0.01 inch (.025 cm), and the diameter of the globe 92 is about 0.022 inch (.056 cm). The globe 92 is shaped and sized to make piercing of the tube assembly 12 unlikely. The globe 92 provides a relatively snug fit for the distal end (90) of the stylet (85) in the distal end 26 of the stylet lumen 24 (as compared to positioning of the stylet in the relatively larger enteral feeding lumen) to enhance the stiffening effect of the stylet.
To further minimize the possibly of piercing of the tube assembly 12, approximately the last two (2) inches (5.1 cm) of the distal end 90 of the wire 85 is fully an-nealed to completely soften the stainless steel to induce stylet deformation rather than tube piercing. In the an-nealed condition, the tensile strength of the annealed portion is reduced to 60,000 to 100,000 P.S.I. (4,222 K9/cm2 to 7 037 K9/cm2) Referring to Figure 5, at least those portions of the wire stylet assembly 20 adapted to be positioned within the stylet lumen 24 are first coated with a layer of TEFLON~
polymer (polytetrafluorethylene), over which is provided a second coating of silicone medical fluid or the like to pro-vide a lubricant to facilitate insertion and withdrawal of the wire stylet assembly 20 into or from the relati~i small stylet lumen 24. It is believed that such lub~ ~tion is enhanced because, as schematically illustrated in Figure 4, the TEFLON~ particles 94 schematically illustrated as small circles in Figure 4, are unevenly deposited along the metal wire stylet assembly 20 so that some particles of TEFLON~ are elevated relative to the remainder thereof.

W O 92/01436 PC~r/US91/04848 2o8~33S:

Over this uneven surface, a continuous layer of a silicone medical fluid 96 (such as Dow Corning 360 silicone medical fluid, or equivalent) is deposited to provide a lubricous coating on the stylet. Although not fully understood, it is believed that because some of the particles 94 of TEFLON~
polymer are laterally elevated relative to others, these elevated particles having a silicone coating thereon are the primary ones making contact with the walls of the stylet lumen 24, with the less elevated particles not making con-tact, thereby reducing drag exerted by the wall against thestylet during insertion and withdrawal. It should also be noted that the wire stylet assembly 20 is substantially shorter than the distance between the Y-site feeding and irrigation ports 52 and 56 and the outlet openings 38 and 40, so that even if the stylet assembly 20 was erroneously or accidentally inserted in the feeding lumen 22, the distal end globe 92 would not reach the feeding lumen outlet open-ings 38 and 40, so that no danger exists that the stylet tip could project through the openings 38 and 48 and thereby possibly injure a patient.
It should also be noted that although the metal wire stylet of the present invention is coated with a silicone medical fluid for lubrication purposes, because the wire stylet is advantageously segregated in a separate stylet lumen and not positioned in the enteral feeding lumen, any danger of enteral feeding or irrigation fluids washing such silicone into the patient's intestinal tract is eliminated, as might be the case if the silicone-coated stylet were positioned in the feeding lumen.
While the invention has been described in connection with one embodiment, one skilled in the art should appreci-ate that the invention is not necessarily so limited and that other embodiments or modifications thereof may be provided without departing from the inventive concept of the 11 ~08733'~

present invention, which is to be determined by reference to the following claims.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A relatively flexible tube (10) for delivery of fluid through a patient's esophagus to the patient's intestinal tract, said tube (10) having a proximal and a distal end (48), and a fluid lumen (22) having a fluid lumen inlet opening adjacent said proximal end of said tube (10) and at least one fluid lumen outlet opening (38,40) adjacent said distal end (48) of said tube (10), characterised in that the tube further includes a stylet lumen (24) separate from said fluid lumen (22), said stylet lumen (24) having a stylet lumen inlet opening (31) adjacent said proximal end of said tube (10) and being longitudinally co-extensive with a substantial length of said fluid lumen (22); and a relatively stiff stylet (85) having a proximal end and a distal end (90), said stylet (85) being removably positioned in said stylet lumen (24) and extending from said stylet lumen inlet opening (31) to adjacent to said fluid lumen outlet opening (38,40), wherein said stylet (85) has a relatively enlarged globe (92) on the distal end (90) thereof, said globe (92) having a diameter slightly less than the diameter of said stylet lumen (24) and said stylet (85) includes a first coating of polytetrafluorethylene (94) applied to and about said stylet (85) and a second coating of silicone (96) applied over and about said polytetrafluorethylene (94) coating.

2. A tube (10) according to claim 1 further characterized in that said stylet lumen (24) is closed except for said stylet lumen inlet opening (31).

3. A tube (10) according to claim 1 or claim 2 characterized in that the diameter of said stylet lumen (24) is substantially smaller than the diameter of the fluid lumen (22).

4. A tube (10) according to any preceding claim characterized in that the tube (10) further includes a Y-site adaptor (16) fixed to the proximal end of the tube (10), said Y-site adaptor (16) including two angularly converging lumen (52,56) in fluid communication with the fluid lumen (22) at the proximal end (32) thereof, each of said angularly converging lumen (52,56) having a Y-site adaptor inlet opening thereon for providing access to said fluid lumen (22) through said Y-site adapter (16).

5. A tube (10) according to claim 4 characterized in that said stylet lumen inlet opening (31) is longitudinally spaced from, and laterally offset from, said Y-site adaptor (16).

6. A tube (10) according to any preceding claim characterized in that said stylet (85) is of metal, a distal portion (90) of said stylet (85) being softened by annealing.

7. A tube (10) according to any preceding claim characterized in that said stylet (85) includes a tapered portion of reducing diameter adjacent to and narrowing toward the distal end (90) thereof to enhance the flexibility of the distal end (90) of said stylet (85).

8. In a relatively flexible tube (10) for delivering fluid through a patient's esophagus to the patient's intestinal tract, said tube (10) having a proximal end, a distal end (48) and at least one lumen extending from adjacent the proximal end of the tube (10) to adjacent the distal end (48) of the tube (10), said lumen having an inlet opening adjacent said proximal end of the tube (10), an improvement characterized as:
a relatively stiff wire stylet (85), said stylet (85) removably positioned in the lumen and extending from the inlet opening to adjacent the distal end (48) of the tube (10), said stylet (85) having a first coating of polytetrafluorethylene (94) applied to and about said wire stylet (85) and a second coating of silicone (96) applied over the about said polytetrafluorethylene (94) coating wherein said enteral feeding tube further includes a Y-site adaptor fixed to said proximal end of said enteral feeding tube, said Y-site adaptor including two angularly converging adaptor lumen in fluid communication with said enteral feeding tube lumen, each of said angularly converging adaptor lumen having a Y-site adaptor inlet opening thereon for providing access to said enteral feeding lumen through said Y-site adaptor.

9. The use for delivery of fluid through a patient's esophagus to the patient's intestinal tract of a tube (10) according to any of the preceding claims.