EP1409061A1

EP1409061A1 - Catheter and stylet assembly and method of catheter insertion

Info

Publication number: EP1409061A1
Application number: EP03707545A
Authority: EP
Inventors: David G. Quinn
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-01-24
Filing date: 2003-01-24
Publication date: 2004-04-21
Also published as: WO2003061752A1; EP1409061A4

Abstract

A catheter and stylet assembly includes a catheter sub-assembly (12), a primary stylet sub-assembly (14) and a secondary stylet sub-assembly (16). The dual stylet assembly facilitates individual manipulation of the stylets to vary catheter tube stiffness as the tube is inserted through the patient’s nose, stomach and duodenum into the jejunum by the method of the invention.

Description

CATHETER AND STYLET ASSEMBLY AND METHOD OF CATHETER INSERTION

RELATED APPLICATION This application incorporates and claims priority from U.S. Provisional

Patent Application Ser. No. 60/351 ,698 filed January 24, 2002.

FIELD OF THE INVENTION

This invention relates generally to catheters and catheter insertion methods. It relates particularly to a catheter and stylet assembly for introducing the catheter into a patient's body cavity, and to a method of doing so.

BACKGROUND OF THE INVENTION

Stylets rather than guidewires are used in medical practice in situations where the clinician desires to push the catheter into a body cavity or vessel. Naso-enteral feeding tubes are inserted with stylets, as are Groshong intravenous catheters. Stylets have constant stiffness over their entire length, however. This can be a disadvantage when the catheter must travel around acute angle bends or through valves or sphincters. Having the stylet constructed with a softer leading portion can be a disadvantage because in its course of travel the catheter may encounter obstructions that will not readily permit the entry of the leading softer portion of the stylet.

There is an increasing interest in placing naso-enteral feeding tubes into the jejunum, rather than the stomach or duodenum. Clinical data shows that in long term (one week or more) nasal-enteral feeding the incidence of aspiration and reflux of feeding formula into the lungs is more than 20%. This reflux occurs because the duodenum has weak peristalsis and is subject to retrograde (reverse) peristalsis that tends to push feeding formula and/or feeding tubes back into the stomach. On the other hand the jejunum has strong peristalsis. This strong peristalsis coupled with the added bends of the tube in the intestine assists in both keeping the tube in place in the jejunum and the formula isolated from the stomach.

There is also an increased understanding of the need for immediate jejunal feeding after gastric or intestinal surgery. Present practice is for the patient to be denied any oral, nasogastric or naso-jejunai feeding post surgically until peristalsis returns. It takes between one and 8 days for peritalsis to return depending on the degree of gastric or intestinal insult caused by the surgery. During this period a suction tube is placed into the stomach via the nasal route to aspirate any gastric juices that build up in the stomach presenting the danger of pulmonary aspiration.

Present practice is to place tubes into the jejunum by endoscopy. Patient sedation is required and gastroenterologists have difficulty pushing the tubes out of the stomach through the pylorus and then past the Ligament of Trietz.

SUMMARY OF INVENTION

An object of the invention is to provide a new and improved catheter and stylet assembly for inserting a feeding tube into a body cavity.

Another object is to provide a catheter and stylet assembly affording almost infinite varying stiffness adjustability over its leading distal portion. Another object is to provide a catheter and stylet assembly with variable stiffness over much of the entire length.

Another object is to allow the insertion of a naso-enteral tube into the jejunum by pushing the tube exteriorly, thereby eliminating the need for endoscopy. Yet another object is to allow the use of a small, very flexible 8Fr feeding tube, rather than stiffer 10Fr or 12fr tubes.

Another object is to prevent coiling of the tube in the stomach during attempts to insert it through the pylorus.

Another objective is to provide a tube that has minimal friction along its entire outside surface from the nares to its tip in the jejunum. Another object is to prevent necrosis in the nasopharynx, pylorus and the Ligament of Trietz by allowing the use of a small flexible δFrtube.

Another object is to incorporate a stylet tip configuration that provides maximum protection against the inadvertent pushing of the stylet through the tube wall.

Another object is to provide a catheter with very lubricious water activated internal and external coating to assure both easy insertion and free movement of the stylets within the tube.

Still another object is to provide a catheter and stylet assembly of the aforedescribed character which includes a multi-lumen tube containing a gastric suction lumen.

The catheter and stylet assembly of the present invention can be used for any medical catheter insertion where a stylet is required. One embodiment described in the present application is used for naso-enteral insertion of a feeding tube into and through the stomach, the duodenum and finally into the jejunum. This use presents some unique requirements for adjustable variability of stylet stiffness. Moderate stiffness is provided for initial insertion through the nasopharynx, the esophagus and into the stomach. Considerably more stiffness is provided to transmit pushing force from outside the patient to the catheter tip as it is pushed through the pylorus into the duodenum and to the Ligament of Trietz. In this regard, conventional feeding tubes resist entry through the pylorus and tend to coil in the stomach. After the stiffer distal tube reaches the Ligament of Treitz, the leading portion of the stylet and catheter is converted to a softer mode so that they can navigate around the acute curve formed by the Ligament of Trietz and into the

Jejunum.

In this Jejunal insertion application, the catheter and stylet assembly of the invention provides moderate stiffness over a long, 25-35" distal length during gastric insertion. Much greater stiffness is provided over the entire length of the catheter during duodenal insertion. Finally, moderate to soft stiffness is provided over 10" to 15" of the distal end as it enters the jejunum. The assembly has two stylets and allows the stylet wire of one to pass through the proximal connector of the other. The assembly also allows irrigation of the inside of the tube through the stylet connection of the assembly to activate a lubricious coating inside the tube lumen (which allows stylet wire manipulation and removal). The coating is also on the exterior surface of approximately the first 35" of the distal tube and tip to minimize friction along the surface of the tube from the insertion point at the nares along its entire length to the tip in the jejunum. The coating adheres to the urethane surface and is activated by contact with water. The stylet that seats itself in the feeding tube "Y" connector contains a stylet wire whose tip end position is most distal. This stylet is referred to as the primary stylet. A secondary stylet connects to the luer lock of the primary stylet and its tip is normally immediately adjacent the primary stylet tip. The overall tube is approximately 60" long. This compares to a conventional feeding tube length of approximately 45". The extra length tube provides for entry into the jejunum.

The method of insertion of a catheter tube using the aforedescribed assembly of the invention comprises the following steps:

1. Seating the already connected primary and secondary stylets into the "Y" connector;

2. using a pre-filled syringe, flushing the tube with water through the secondary stylet connector to activate the lubricious coating on the entire length of the tube's internal lumen;

3. retracting the secondary stylet to a wire mark located 35" distal from the stylet connector;

4. dipping approximately 6" of the tube and tip in water;

5. inserting the tube in a conventional manner while, at the same time, passing the tube at the point of entry at the nares through a moist gauze pad to activate the external lubricant; 6. after the tube enters the stomach, pushing in and re-connecting the secondary stylet connector to the primary connector;

7. under flouroscopy, advancing the primary and secondary stylet stiffened catheter into the duodenum to the Ligament of Trietz;

8. retracting the secondary stylet to a wire mark located 12" distal from the primary stylet connector;

9. under flouroscopy, advancing the tube tip to its desired final location, beyond the Ligament of Trietz in the jejunum;

10. while holding the "Y" connector, retracting the secondary stylet and discarding it;

11. then, while holding the Y connector, retracting the primary stylet ; , carefully so as to not dislodge the tube from the jejunum; and

12. securing the catheter with a bandage and beginning the feeding operation. In other versions of the invention, a multi-lumen tube containing a suction lumen in addition to the feeding lumen accesses both the stomach and the jejunum. The stylet system invention can also be used in this multi- lumen configuration and provides for both jejunal feeding and gastric suction.

BRIEF DESCRIPTION OF THE DRAWINGS The invention, including its construction and method of operation, is illustrated more or less diagrammatically in the drawings, in which:

FIG. 1 is a side elevational view of a common flow-through stylet connector;

FIG. 2 is an end view of the connector; FIG. 3 is a sectional view of the connector showing the flow-through lumen and the socket for the wire stylet;

FIG. 4 is a sectional view of the connector with a stylet in place;

FIG. 5 is a side elevational view of the assembled primary stylet; FIG. 6 is a side elevational view of a short segment of vinyl tubing;

FIG. 7 is a side elevational view of a male luer lock connector designed to fit over a delivery tube;

FIG. 8 is a side elevational view of the flow-through connector shown in FIG. 5, assembled to the male luer lock in FIG. 7 by means of both parts being inserted and glued into the short segment of vinyl tubing;

FIG. 9 is a cross sectional view of the assembly in FIG. 8;

FIG. 10 is a side elevational view of the primary and secondary stylets connected, the tip of the secondary stylet being slightly behind the tip of the primary stylet;

FIG. 11 is a cross sectional view of the primary and secondary stylets unconnected, but with the secondary stylet wire inserted through the flow- through lumen of the primary stylet;

FIG. 12 shows both stylets' distal ends as they would be positioned in a feeding tube with both stylet connectors attached;

FIG. 13 is a cross sectional view through the tube in FIG. 12, at line 13-13, the main body of the primary stylet and through the tip of the secondary stylet, the tube being 8Fr with an 0.080" internal lumen and the stylet wire having a 0.014" OD; FIG. 14 is a cross section of the tube in FIG. 12 and the main bodies of both stylets, at line 14-14;

FIG. 15 is a side elevational view of the invention assembly with the stylet connectors assembled, but not seated, in the feeding tube "Y" connector with a cross sectional view of the tube and tip showing the position of the stylets;

FIG. 16 shows the connected two stylet assembly seated in the "Y" connector with the distal tip of the primary stylet positioned just behind the tube tip;

FIG. 17 shows the two stylet assembly with the secondary stylet retracted;

FIG. 18 shows both stylets disconnected from each other and from the "Y"; FIG. 19 shows the secondary stylet removed and the primary stylet seated in the "Y" as it would be in a normal feeding tube insertion procedure;

FIG. 20 illustrates the almost infinite stiffness adjustability of the catheter, i.e., there are three potential stiffness zones in the tube, all adjustable;

FIG. 21. shows the secondary stylet retracted approximately 35" so that gastric insertion can be carried out with normal stylet stiffness;

FIG. 22. shows the secondary stylet re-seated in the "Y" connector;

FIG. 23. shows both stylets remaining in place for maximum stiffness, the catheter having been pushed through the pylorus and into the duodenum up to the Ligament of Trietz;

FIG. 24 shows the secondary stylet retracted approximately 12", the primary stylet remaining in place, so as to provide reduced but adequate stiffness so that the tube can be pushed around the Ligament of Trietz into the jejunum;

FIG. 25 shows the secondary stylet removed after final placement of the tip in the jejunum;

FIG. 26 illustrates the tube ready for infusion of nutrients after careful removal of the secondary stylet; FIG. 27 is a side elevational view of a mid-port bolus in a feeding tube wherein the dual stylet features of the invention are employed;

FIG. 28 is a top plan view of the bolus of FIG. 27; and

FIG. 29 is a longitudinal sectional view taken along line 29-29 of FIG. 28.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, and first to FIGURES 15-20, a catheter and stylet assembly embodying features of the invention is shown generally at 10. The assembly 10 comprises a catheter tube sub-assembly 12, a first stylet sub-assembly 14 and a second stylet sub-assembly 16. Referring now also to FIGURES 1-14, the catheter tube sub-assembly

12 comprises an 8 French (Fr) tube 20 having a bolus tip 22 on its distal end. A conventional Y-connector 24 is mounted on its proximal end. The Y-connector has a conventional inlet port 26 at its proximal end.

The first stylet sub-assembly 14 comprises a molded acrylic connector sleeve 28 and a primary twisted wire stylet 30. The proximal end 32 of the stylet 30 is force fit into a slot 34 formed within, and on the side, of a lumen 36 extending longitudinally through the connector sleeve 28. The distal end 37 of the stylet extends approximately 48 inches from the nose of the sleeve 28.

The connector sleeve 28 can be threaded into the proximal end port 26 of the Y-connector 24. Its stylet 30 then extends through the tube 20 as illustrated in FIGURE 19.

The second stylet sub-assembly 16 comprises a molded acrylic connector sleeve 38 identical to the sleeve 28. A secondary twisted wire stylet 40 has a proximal end 42 which is force fit into a slot 44 formed inside, and on one side of, a lumen 46 extending longitudinally through the connector sleeve 38. The distal end 47 of the secondary stylet 40 extends approximately 52 inches from the nose of the sleeve 38.

The second stylet sub-assembly 16 also comprises an acrylic male luer lock fitting 50 and a vinyl sleeve 52. The vinyl sleeve 52 connects the luer lock fitting 50 to the connector sleeve 38. The catheter tube sub-assembly 12, first stylet sub-assembly 14 and second stylet sub-assembly 16 are joined together to form the assembly 10 in the manner illustrated in FIGURE 16. In this assembly 10, the relationship of the stylets 30 and 40 are shown in FIGURES 12-14.

Referring now to FIGURES 21-25, FIGURE 21 shows stylet sub- assembly 16 disconnected from stylet sub-assembly 14 and its stylet 28 withdrawn approximately 35 inches. In this configuration, the assembly provides a more flexible tube 20 for insertion through a patient's nose.

In FIGURE 22, the first and second stylet sub-assemblies 14 and 16 are connected. In this configuration both stylet tips are positioned just behind tube tip 22. This facilitates passage of the tube 20 through the Pyloric valve to the position shown in FIG. 23. When a more flexible distal end of the tube 20 is needed, the second stylet sub-assembly 16 is disconnected from the first stylet subassembly 14 using the luer lock fitting. The secondary stylet can then be withdrawn a short distance (12" as seen in FIGURE 24). This permits easy passage into the duodenum, for example.

Referring now to FIGS. 27-29, a modified application of the invention is illustrated in the form of a catheter and stylet assembly 110 (with parts removed). In the assembly 110, the primary and secondary stylets 30 and 40 extend through a dual lumen catheter tube sub-assembly 112. The catheter tube sub-assembly 112 includes an 8 Fr dual lumen tube 120, a mid-port bolus 124 and a 5 Fr single lumen tube 128. The stylets 30 and 40 extend through the lumens and the bolus in the manner illustrated.

The use of a lubricious coating in the catheter insertion process has previously been described. The lubricant is a combination of methyl cellulose and polyvinylpyrolidone. The lubricaniadheres to the tube surface and becomes extremely slippery when contacted by water.

While preferred embodiments of the invention have been described, it should be understood that the invention is not so limited and modifications may be made without departing from the invention. The scope of the invention is defined by the appended claims, and all devices that come within the meaning of the claims, either literally or by equivalence, are intended to be embraced therein.

Claims

1. A catheter and stylet assembly, comprising: a) a catheter tube having a proximal end and a distal end; b) a primary stylet extending into said tube from said proximal end; and c) a secondary stylet extending into said tube from said proximal end; d) said primary and secondary stylets being independently movable longitudinally of said tube to adjust the stiffness of said tube.

2. The catheter and stylet assembly of Claim 1 further characterized in that: a) said tube is an 8 Fr size tube.

3. The catheter and stylet assembly of Claim 2 further characterized by and including: a) a bolus on the distal end of said tube.

4. The catheter and stylet assembly of Claim 1 further characterized in that: a) said primary stylet includes a proximal end seated in a sleeve fitting; b) said secondary stylet includes a proximal end seated in a sleeve fitting; c) said primary and secondary stylet fittings being releasably connected by an intermediate sleeve fitting.

5. A stylet sub-assembly, comprising: a) a stylet having a proximal end and a distal end; b) a sleeve fitting having an axial passage extending longitudinally therethrough from end-to-end; and c) a seat formed in said fitting on one side of said axial passage; d) said proximal end of said stylet being mounted in said seat.

6. The stylet sub-assembly of Claim 5 further characterized in that: a) said seat comprises a slot formed inside said sleeve on one side of said axial passage; b) said proximal end of said stylet being force-fit into said slot.

7. A catheter and stylet assembly, comprising: a) a catheter tube sub-assembly including a catheter tube having a distal end and a proximal end, said tube having a connector on its proximal end; and b) a first stylet sub-assembly including a primary stylet having distal and proximal ends, said first stylet sub-assembly also including a first stylet fitting in which the proximal end of said primary stylet is seated; and c) a second stylet sub-assembly including a secondary stylet having distal and proximal ends, said secondary stylet sub-assembly also including a second stylet fitting in which the proximal end of said secondary stylet is seated; d) said first stylet fitting being releasably seated in said connector with said primary stylet extending into said tube and said secondary stylet fitting being releasably connected to said first stylet fitting with said secondary stylet extending into said tube.

8. The catheter and stylet assembly of Claim 7 further characterized in that: a) said second stylet sub-assembly further including a sleeve fitting which connects said first stylet fitting to said second stylet fitting.

9. The catheter and stylet assembly of Claim 7 further characterized in that: a) said secondary stylet has a visible mark formed on it approximately 12" from its stylet connector.

10. The catheter and stylet assembly of Claim 7 further characterized in that: a) said catheter tube assembly includes a catheter tube containing two lumens.

11. The catheter and stylet assembly of Claim 7 further characterized in that: a) said catheter tube is a single lumen, 8 Fr size tube having a bullet nose bolus on its distal end.

12. The catheter and stylet assembly of Claim 10 further characterized in that: a) said catheter tube assembly includes an 8 Fr catheter tube containing two lumens and a smaller diameter catheter tube containing a single lumen; b) said tubes being connected by a bolus having a side port.

13. The catheter and stylet assembly of Claim 12 further characterized in that: a) said single lumen catheter tube is a 5 or 6 Fr size tube.

14. The catheter and stylet assembly of Claim 11 further characterized in that: a) said catheter tube is coated inside and out adjacent said bolus with a water soluble lubricant.

15. A method of inserting a catheter tube into a patient's body cavity comprising the steps of: a) providing a catheter tube having a lumen extending between a distal end and a proximal end; b) inserting first and second stylets into said tube from said proximal end whereby said stylets are in side-by-side relationship in at least a portion of said tube; c) introducing said catheter tube, distal end first, into an access passage to said body cavity and d) manipulating said stylets longitudinally relative to each other in said tube to adjust the stiffness of said tube as it travels through said access passage.

16. The method of Claim 15 further characterized by and including the step of: a) coating the inside of said lumen with a water activated lubricant before inserting said stylets.

17. A method of inserting a catheter tube into a patient's jejunum comprising the steps of: a) seating the connected primary and secondary stylets into a "Y" connector; b) flushing the tube with water through the tube to activate a lubricious coating in the tube's internal lumen; c) retracting the secondary stylet to a wire mark located a predetermined distance distal from the stylet connector; d) dipping approximately 6" of the tube and tip in water; e) inserting the tube while, at the same time, passing the tube at the point of entry at the nares through a moist gauze pad to activate the external lubricant; f) after the tube enters the stomach, re-connecting the secondary stylet connector to the primary connector; g) advancing the primary and secondary stylet stiffened catheter into the duodenum to the Ligament of Trietz; h) retracting the secondary stylet to a wire mark located a predetermined distance distal from the primary stylet connector; i) advancing the tube tip to its desired final location, beyond the Ligament of Trietz in the jejunum; j) while holding the "Y" connector, retracting the secondary stylet; and k) then, while holding the "Y" connector, retracting the primary stylet carefully so as to not dislodge the tube from the jejunum.

18. The method of Claim 15 further characterized in that: a) said catheter tube includes a multi-lumen segment and a single lumen segment connected by a mid-port bolus.