EP0591192A1 - Improved enteral feeding tube - Google Patents

Abstract

A relatively flexible, dual port enteral feeding tube (10) for delivery of fluid through a patient's esophagus to the patient's intestinal tract has an enteral feeding port (22) and a relatively small stylet orifice (24) separated from the enteral feeding orifice (22) and extending in the same plane and a certain length as the enteral feeding orifice (22). The stylet port (24) has a relatively rigid removable metal stylus (85) having an annealed conical distal portion. The stylus (85) has a polytetrafluoroethylene coating and a silicone coating on the polytetrafluoroethylene. The tube (10) also has a Y-site adapter (16) attached to the proximal end of the tube (10). The Y-adapter (16) has Y-shaped openings allowing access to the enteral feeding port (22).

Description

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 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 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 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 car 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 entera 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 closed 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.

It is a further object and aspect of the present inven- tion to provide an enteral feeding tube wire stylet with a coating of TEFLON^® polymer (polytetrafluorethylene) , over which a lubricous coating of silicone is applied. It is believed that such a lubricous coating arrangement facili¬ tates 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. BRIEF DESCRIPTION OF DRAWINGS Figure 1 is a plan view of an improved enteral feedin 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 1; 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 1; and

Figure 5 is a schematic illustration on an enlarged scale of the distal tip portion of the wire stylet shown i Figure 4 but shown with TEFLON^® and silicone coatings sche matically represented on the stylet according to the prese 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 JLO_. 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 en 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 2±, approximately 0.04 inch (.10 cm) in diameter the distal end 2_6 of which is closed as by dead-ending within the tube assembly 12 by a plug or the like. The proximal end 23. 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 3_1 provided in a laterally offset face 3_3 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 3J5 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 4j) 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 4_1 to assist in properly positioning the enteral feeding tube 10.

The bolus weight assembly 14 includes a cavity 4 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 in positioning the enteral feeding tube in the patient's diges¬ tive system and maintaining such positioning over an extended period. A radiopaque line 4J5 may be provided on the surface of the bolus weight assembly 14 to assist in locating the position of the distal end 4J5 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 such as DOW PELLETHANE^® thermoplastic with Barium Sulfate (BaS0₄) mixed throughout such material to provide a radi¬ opaque construction of the entire tube and bolus assemblie 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 patien 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 5() including a feeding port lumen 5_2. in fluid communication with the proximal end 32 of the entera 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 entera feeding lumen 22. The feeding port lumen 52 and irrigatio 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 lum is also shaped and sized to receive a standard stepped feeding tube connector of a conventional enteral administr 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 j52_. of which is adapted to be inserted in the feeding port or lumen 52 with the cup-shaped recess 6__%_ 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- 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 j66 extending beyond the closure 60, the web being provided with a finger-grip projection ___ to facili- tate insertion and withdrawal of the closure 60 in or from the feeding port lumen 52.

Connected to the proximal end of the irrigation tube portion 54 is a flexible arm 2_l and a hollow tubular adaptor 72. having a bore 7.3. 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 7__ having a finger-grip projection 7_6 to facilitate insertion and with- drawal of the adaptor 72 in or from the irrigation port lumen 56. Connected to the outer end of the web 74 is a second flexible arm 7_8, 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 supported on a web _2_, the outer end of which is provided with a finger-grip projection .84_. to facilitate insertion o 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 wir stylet assembly 20 comprises a stainless steel wire .85_ of appropriate strength (290,000 to 300,000 P.S.I, tensile strength) (20,407 ^<9/cm² to 21,111 ^K9/cm²) and rigidity to appropriately stiffen the enteral feeding tube 10 for inse tion through the nose or mouth, the esophagus and into the stomach or small intestines. The wire 85 is fully hardene along the full length thereof except adjacent the distal e thereof which will be subsequently discussed.

The proximal free end of the wire 85 is looped back o itself to form a finger pull or wire loop j$6_ by fixing the free end to the shaft j$8. 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 j39. havin an adhesive-coating on the inner surface thereof and heati 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 exteri side of the stylet opening saddle 18 when the stylet is in serted in the stylet lumen inlet opening 30 and bottomed i the stylet lumen 24. It should be noted that the stylet opening saddle is longitudinally spaced and laterally offs from the Y-site connector for convenience on stylet inser- tion. Additionally, this positioning, as opposed to a location 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 <K) of the wire 85, as shown in Figure 4 is tapered in a converging manner commencing at a point 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 Ϊ32.. 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 ^Kg/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 relatively small stylet lumen 24. It is believed that such lubrication is enhanced because, as schematically illustrated in Figure 4, the TEFLON^® particles £4 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. Over this uneven surface, a continuous layer of a silicone medical fluid 6. (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 i 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 th 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 the stylet 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 dista end globe 92 would not reach the feeding lumen outlet open¬ ings 38 and 40, so that no danger exists that the stylet ti 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 th present invention, which is to be determined by reference to the following claims.

Claims

1. In a relatively flexible tube (10) for delivery of fluid through a patient's esophagus to a patient's intesti¬ nal tract, the tube (10) having a proximal end and a distal end (48) , the tube (10) having a fluid lumen (22) with a fluid lumen inlet opening adjacent the proximal end of the tube (10) and at least one fluid lumen outlet opening (38,40) adjacent the distal end (48) of the tube (10), the improvement characterized by: a stylet lumen (24) separate from the fluid lumen (22) said stylet lumen (24) having a stylet lumen inlet opening

(31) adjacent the proximal end of the tube (10) , said style lumen (24) longitudinally co-extensive with a substantial length of the fluid lumen (22) ; and, a relatively stiff stylet (85) having a proximal end and a distal end (90) , said stylet (85) removably positione in said stylet lumen (24) and extending from said stylet lumen inlet opening (31) to adjacent the fluid lumen outlet opening (38,40) .

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

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

4. A tube (10) as in claim 1 characterized in that th 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) of fluid lumen (22) , 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 adaptor (16) .

5. A tube (10) as in 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) as in claim 1 characterized in that said stylet (85) is constructed of metal and further charac- terized in that a distal portion (90) of said stylet (85) is annealed to soften the distal portion (90) of said stylet (85).

7. A tube (10) as in claims 1, 2, 3, 4, 6 , and 8 fur¬ ther characterized in that 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.

8. A tube (10) as in claim 1 characterized in that said stylet (85) includes a tapered portion of reducing diameter adjacent to and narrowing toward the distal end (90) of said stylet (85) to enhance the flexibility of the distal end (90) of said stylet (85) .

9. A tube (10) as in claim 8 further characterized in that said stylet (85) has a.relatively enlarged globe (92) on the distal end (90) of said stylet (85) , said globe (92) having a diameter slightly less than the diameter of said stylet lumen (24) .

10. In a relatively flexible tube (10) for deliverin fluid through a patient's esophagus to the patient's intes tinal tract, said tube (10) having a proximal end, a dista end (48) and at least one lumen extending from adjacent th 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 improvemen 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 polytetra¬ fluorethylene (94) applied to and about said wire stylet (85) and a second coating of silicone (96) applied over and about said polytetrafluorethylene (94) coating.

11. A method for placing fluids in a patient's intes¬ tinal tract comprising the steps of: placing a stylet (85) in a stylet lumen inlet opening (31) of a stylet lumen (24) of a relatively flexible tube (10) having a proximal end and a distal end (48) , the tube (10) having at least a fluid lumen (22) and a stylet lumen (24) separate from the fluid lumen (22) , the fluid lumen (22) having a fluid lumen inlet opening adjacent the proxi¬ mal end of the tube (10) and at least one fluid lumen outle opening (38,40) adjacent the distal end (48) of the tube

(10) , the stylet lumen inlet opening (31) located adjacent the proximal end of the tube (10) , the stylet lumen (24) longitudinally co-extensive with a substantial length of th fluid lumen (22) so that the stylet (85) extends from the stylet lumen inlet opening (31) to a point adjacent the fluid lumen outlet opening (38,40); pushing the distal end (48) of the tube (10) containin the stylet (85) located in the stylet lumen (24) through a patient's nostril and down the patient's alimentary tract to the patient's intestinal tract; removing the stylet (85) from the stylet lumen (24) while leaving the tube (10) in position through the patient's nostril, alimentary tract, and intestinal tract; and, connecting the fluid lumen inlet opening to a source of fluid whereby fluid passes from the source of fluid through the fluid lumen (22) to the fluid lumen outlet opening (38,40) where the fluid leaves the tube (10) and enters the patient's intestinal tract.

12. A relatively flexible tube (10) for delivery of fluid through a patient's esophagus to the patient's intes¬ tinal tract, said tube (10) having a proximal and a distal end (48) , said tube (10) comprising: 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) ; 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) 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) .

13. A tube (10) as in claim 12 wherein said stylet lumen (24) is closed except for said stylet lumen inlet opening (31) . 16

14. A tube (10) as in claim 12 wherein said fluid lumen (22) has a diameter substantially greater than the diameter of said stylet lumen (24) .

15. A tube (10) as in claim 12 characterized in tha said stylet (85) is constructed of metal and further char terized in that a distal portion (90) of said stylet (85) annealed to soften the distal portion (90) of said stylet (85).

16. A tube (10) as in claim 12 further characterize in that said stylet (85) includes a first coating of polytetrafluorethylene (94) applied to and about said sty (85) and a second coating of silicone (96) applied over a about said polytetrafluorethylene (94) coating.

17. A tube (10) as in claim 12 characterized in tha said stylet (85) includes a tapered portion of reducing diameter adjacent to and narrowing toward the distal end (90) of said stylet (85) to enhance the flexibility of th distal end (90) of said stylet (85) , said stylet (85) als having a relatively enlarged globe (92) on the distal end (90) of said stylet (85) , said globe having a diameter slightly less than the diameter of said stylet lumen (24) .