AU656143B2 - Improved enteral feeding tube - Google Patents

Description

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OPI DATE 18/02/92 AOJP DATE 26/03/92 APPLN. ID 83084 91 PCT NUMBER PCT/US91/04848 INTERNA TREATY (PCT) (51) International Patent Classification 5 (11) International Publication Number: WO 92/01436 A61J 15/00 Al (43) International Publication Date: 6 February 1992 (06.02.92) (21) International Application Number: PCT/US91/04848 (74) Agents: SMITH, Montgomery, Sherwood Medical Company, 1915 Olive Street, St. Louis, MO 63103-1642 (22) International Filing Date: 16 July 1991 (16.07.91) (US) et al.

Priority data: (81) Designated States: AT (European patent), AU, BE (Euro- 555,969 19 July 1990 (19.07.90) US pean patent), CA, CH (European patent), DE (European patent), DK (European patent), ES (European patent), FR (European patent), GB (European patent), GR (71) Applicant: SHERWOOD MEDICAL COMPANY [US/ (European patent), IT (European patent), JP, LU (Euro- US]; 1915 Olive Street, St. LGis, MO 63103-1642 pean patent), NL (European patent), SE (European patent).

(72) Inventors: SCHRADER, Eugene, Francis 2335 Edwards, St. Louis, MO 63110 WEILBACHER, Eugene, Elmer 1312 Bridge Creek Trail, Ellisville, MO 63021 Published BODICKY, Raymond, Otto 5051 Lampglow With international .'arch report.

Court, St. Louis, MO 63129 SCHNEIDER, James, Gerard 12805 Polo Parc, St. Louis, MO 63146 (US).

656143 (54) Title: IMPROVED ENTERAL FEEDING TUBE 2 ff (57) 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 luimen (22) and longitudinally co-exten"ive with a substantial length of the enteral feeding lumen The stylet 'men (24) has a removable relatively stiff metal stylet the stylet (85) with a tapered annealed distal portion. The stylet a coating of polytetrafluorethylene and a coating of silicone over the polytetrafluorethylene. The tube (10) also has a Y-site -tor (16) fixed on the proximal end of the tube The Y-site adaptor (16) has Y-site openings through which access may be i the enteral feeding lumen (22).

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WO 92/01436 PCI/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 and extended placement. Because these tubes are conventionally constructed of soft, flexible material, such as polyurethane or the like, a relatively stiff but narrow metal stylet As 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 contents, auscultation by stethoscope placed over the stomach 3C 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 o d r i1 i i i 1 i \i j i i i t i i i

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I I I t e 1 aI l I is sometimes necessary to reinsert the stylet into the feeding tube to alter the location thereof. Utilizing conventional enteral feeding tubes and stylets, remo 1, 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 stiffness, friction between the tube lumen and the stylet, and the danger of the stylet piercing the tube lumen or protruding 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 contamination thereof in the feed lumen of a conventional enteral feeding tube by the patient's bodily fluids is sometimes considered undesirable or disconcerting to health care workers.

DISCLOSURE OF INVENTION It is the object of the present invention to overcome or substantially ameliorate the above disadvantages.

.4- (n:\1ibTTlO3:I0 9AD -3- There is disclosed herein a combinatin of a flexible tube a and relatively stiff stylet, the tube being soft, having no predetermined linear shape and being for delivery of fluid through a patient's oesophagus to the patient's intestinal tract, said tube having a proximal end, a distal end, a fluid lumen and a separate stylet lumen, the fluid lumen 6 having a fluid lumen inlet opening adjacent said proximal end of said tube and at least one fluid lumen outlet opening adjacent said distal end of said tube, and said stylet lumen having a stylet lumen inlet opening adjacent said proximal end of said tube and being longitudinally co-extensive with a substantial length of said fluid lumen; said stylet having a proximal end and a distal end, and being removably positioned in said stylet lumen and extending in use from said stylet lumen inlet opening to adjacent said fluid lumen outlet opening.

It is preferred that the wire stylet be provided with a coating of TEFLON@ polymer (polytetrafluorcethylene), over which a lubricous coating of silicone is applied.

It is believed that such a lubricous coating arrangement facilitates insertion and T5 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 lubrication 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.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: sye a i It ia InA1ibTT1iO339AAD WO 92/01436 PCT/US91/04848 4 .n .rr DEnr PTIrnmTO OF PlmP Tc 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 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 in Figure 4 but shown with TEFLON* and silicone coatings schematically 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 conventional bolus weight assembly 14. Fixed to the proximal end of the tube assembly 12 is a Y-site connector, adaptor and a 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 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- i '4 AI

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*1 4 i WO 92/01436 PCT/US91/04848 prises a relatively large diameter primary or enteral feeding lumen 22 adjucent a relatively small diameter, separate secondary or stylet lumen 24, approximately 0.04 inch 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 communication 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 longitudinally-spaced enteral feeding lumen outlets 38 and spaced at 180" about the tube periphery in fluid communication 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 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 approximately 0.75 gram each, the function of which is to assist in positioning the enteral feeding tube in the patient's digestive 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

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9 i H.- WO 92/01436 PCT/US91/04848 6 such as DOW PELLETHANE thermoplastic with Barium Sulfate (BaSO 4 mixed throughout such material to provide a radiopaque 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 C-nstructed of a plastic material such as polyvinyl chlor e, or the like and is fixed to the proximal end of the tubz assembly 12. The Y-site connector comprises a hollow feeding 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 irrigation 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 administration tubing set. The irrigation port lumen 56 is also adapted to receive an adaptor, as will be hereinafter discussed, 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 therefrom.V Connected to the proximal end of the feeding tube portion 50 by a flexible arm 58 is a cup-shaped closure as best seen in Figure 3, the closed end 62 of which is *'1 Ph L k. 11t i ,iir-i i WO 92.(01436 PCr/US9 /04848 adapted to be inserted in the feeding port or lumen 52 with the cup-shaped recess 64 on the exterior side of the closure 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 closure arrangement is considered to be advantageous over prior art closures for feeding lumen wherein the closure is reversed 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 .xtending beyond the closure 60, the web being provided with a finger-grip projection 68 to facilitate 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 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 withdrawal of the adaptor 72 in or from tho irrigation port lumen 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

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1i ~L WO 92/01436 PCT/US91/04848 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/cm 2 to 21,111 KO/cm 2 and rigidity to appropriately stiffen the enteral feeding tube 10 for insertion 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 inserted 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 insertion. 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 90 of the wire 85, as shown in Figure 4, is tapered in a converging manner commencing at a point

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WO 92/01436 PCT/US91/04848 9 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 as indicated in Figure 4, is about 0.02 inch (.05 cm), at point 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 1li, approximately the last two inches (5.1 cm) of the distal end 90 of the wire 85 is fully annealed to completely soften the stainless steel to induce stylet deformation rather than tube piercing.. In the annealed condition, the tensile strength of the annealed portion is reduced to 60,000 to 100,000 P.S.I. (4,222 K9/cm 2 to 7,037 K9/cm 2 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 I second coating of silicone medical fluid or the like to provide 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 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.

WO 92/01436 PCT/US91/04848 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 contact, 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 distal end globe 92 would not reach the feeding lumen outlet openings 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 i 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 i with one embodiment, one skilled in the art should appreciate 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

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Li I- 'L I i WO 92/01436 PCT/US91/04848 present invention, which is to be determined by reference to the following claims.

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Claims (14)

1. A combination of a flexible tube and a relatively stiff stylet, the tube being soft, having no predetermined linear shape and being for delivery of fluid through a patient's oesophagus to the patient's intestinal tract, said tube having a proximal end, a distal end, a flid lumen and a separate stylet lumen, the fluid lumen having a fluid lumen inlet opening adjacent said proximal end of said tube and at least one fluid lumen outlet opening adjacent said distal end of said tube, and said stylet lumen having a stylet lumen inlet opening adjacent said proximal end of said tube and being longitudinally co- extensive with a substantial length of said fluid lumen; said stylet having a. proximal end and a distal end, and being removably positioned in said stylet lumen and extending in use from said stylet lumen inlet opening to adjacent said fluit. .amen outlet opening.

2. A combination according to claim 1, wherein said stylet lumen is closed except for said stylet lumen inlet opening.

3. A combination according to claim 1 or claim 2, wherein the diameter of said stylet lumen is substantially smaller than the diameter of the fluid lumen.

4. A combination according to any preceding claim, wherein the tube further includes a Y-site adaptor fixed to the proximal end of the tube, said Y-site adaptor including two angularly converging lumen in fluid communication with the fluid lumen at the proximal end thereof, each of said angularly converging lumen 20 having a Y-site adaptor inlet opening thereon for providing access to said fluid lumen through said Y-site adaptor.

5. A combination according to claim 4, wherein said stylet is shorter than the distance from said Y-site adaptor to said fluid lumen outlet opening.

6. A combipation according to claim 4 or claim 5, wherein said stylet lumen inlet opening is longitudinally spaced from and laterally offset from said Y-site adaptor.

7. A combination according to any one of claims 4 to 6, wherein closure means is provided for said Y-site adaptor, said closure means comprising a cup-shaped closure for insertion into said Y-site adaptor inlet opening and connected to said Y-site adaptor by a flexible arm.

8. A combination according to any preceding claim, wherein said stylet is of metal, a distal portion of said stylet being softened by annealing.

9. A combination according to any preceding claim, wherein said stylet includes a tapered portion of reducing diameter adjacent to and narrowing toward the distal end thereof to enhance the flexibility of the distal end of said stylet.

A combination according to claim 9, wherein said stylet has a b relatively enlarged globe on the distal end thereof, said globe having a diameter slightly z less than the diameter of said stylet lumen. ;I In:\llbTT100339:IAD t 1 i i^ I Sf -13-

11. A combination according to any preceding claim, wherein said stylet includes a first coating of polytetrafluoroethylene applied to and about said stylet and a second coating of silicone applied over and about said polytetrafluoroethylene coating.

12. A combination according to any one of claims 8 to 11, wherein said stylet includes a wire loop at the proximal end thereof, said loop being fixed to said stylet by heat shrinkage tubing having an adhesive coating on the inner face thereof.

13. A combination according to any preceding claim, further comprising a bolus weight attached to the distal end thereof.

14. A combination of a flexible tube and stiff stylet, substantially as described herein with reference to the accompanying drawings. DATED this Eighth Day of November 1994 Sherwood Medical Company Patent Attorneys for the Applicant SPRUSON FERGUSON 'I I I~ [n:\libTT)00339:iAD