Patent Publication Number: US-6223070-B1

Title: Indwelling catheter

Description:
This application is a continuation of Ser. No. 09/039,636 filed Mar. 16, 1998, U.S. Pat. No. 5,941,823. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The present invention generally relates to medical devices and, more specifically, to an indwelling catheter. 
     BACKGROUND OF THE INVENTION 
     The following specification, in both the background and in the detailed description, describes the use of the catheter of the present invention in the areas of gastrostomy and gastrojejunostomy and cecostomy. While the present invention finds particular use in these fields, those skilled in the art will recognize that the catheter of the present invention may be used in any application where connection from the outside of the patient&#39;s body to an internal cavity within the body is desired, such as in the biliary tree, the liver, the kidney, etc. 
     With reference to gastrostomy and gastrojejunostomy procedures as a particular example, catheters for use in these procedures are inserted directly through the abdominal wall of the patient and into the stomach. Gastrostomy catheters can then be used for feeding the patient directly into the stomach, wherein nourishing substances are inserted into an external opening in the catheter and are transported by the catheter to the interior of the patient&#39;s stomach. With the gastrojejunostomy catheter, the distal portion of the catheter inside the patient is long enough to be positioned in the jejenum, such that feeding can bypass the stomach entirely. 
     FIG. 1 illustrates a prior art design for such catheters, indicated generally at  10 . Because these catheters are left in place for extended periods of time, and because they extend externally from the patient, it is necessary that these catheters have some retention means for preventing the catheter from being accidentally removed from the patient. The catheter  10  of FIG. 1 uses a single, pull string-locked loop inside the stomach for catheter retention. As can be seen by the drawing, the proximal end  12  of the catheter  10 , the fitting  14 , the pull string  16  and the cuff  18  all protrude out of the patient&#39;s abdominal wall for a distance of several centimeters. This protruding proximal catheter section can be a source of great distress for many patients. In addition to the emotional stress of having a catheter tube protruding from the stomach, nearly all patients find that lying on the catheter or covering the catheter is uncomfortable. Such prior art catheters are particularly problematic with pediatric patients, who cannot leave the catheter alone and will usually end up pulling the catheter out. 
     There is therefore a need for a catheter which is designed to extend from an interior cavity of the patient to a point external of the patient, wherein the portion of the catheter which lies external to the patient is minimized. In addition, the catheter must provide means for securely anchoring the catheter in place, such that it is difficult for the catheter to be accidentally removed. The present invention is directed toward meeting these needs. 
     SUMMARY OF THE INVENTION 
     The present invention relates to an indwelling catheter having an extremely low profile proximal section which is situated external to the patient&#39;s body when the catheter is in place. The external portion is preferably in the form of a “trap door”, including a flat base portion that lies against the patient&#39;s skin and a flat, hinged cover which is operative to seal the proximal opening of the catheter when not in use. In order to retain the catheter and prevent it from being accidentally dislodged, the catheter includes a series of helical coils which are unformed during catheter insertion and then automatically reform in order to hold the catheter in place internally. The catheter is self-adjusting in that fewer or greater loops will automatically reform depending upon the thickness of the patient&#39;s abdominal wall. The catheter of the present invention is therefore self-adjusting in order to accommodate the distance between the abdominal wall and the stomach. 
     In one form of the invention an indwelling catheter is disclosed, comprising an elongate body having a proximal end, a distal end and an interior lumen therethrough; an external flange coupled to the proximal end; and a plurality of helical coils formed in the body between the proximal and distal ends; wherein the helical coils may be straightened out by placing a stiffener into the interior lumen in order to facilitate placement of the catheter between an external surface of a patient and an interior cavity thereof; and wherein at least one of the helical coils automatically reforms when the stiffener is removed from the interior lumen after placement of the catheter, such that the flange is held against the external surface of the patient and the at least one helical coil is held against an interior surface of the cavity. 
     In another form of the invention a method of placing an indwelling catheter is disclosed, comprising the steps of: (a) providing an indwelling catheter, comprising an elongate body having a proximal end, a distal end and an interior lumen therethrough; an external flange coupled to the proximal end; and a plurality of helical coils formed in the body between the proximal and distal ends; (b) inserting a stiffener into the interior lumen such that the helical coils are straightened out; (c) inserting the catheter/stiffener through an external surface of a patient such that the distal end of the elongate body lies within an internal cavity of the patient and the external flange abuts the external surface of the patient; and (d) holding the elongate body in place while withdrawing the stiffener from the interior lumen, such that at least one of the helical coils reforms within the internal cavity, such that the flange is held against the external surface of the patient and the at least one helical coil is held against an interior surface of the cavity. 
     In another form of the invention an indwelling catheter is disclosed, comprising an elongate body having a proximal end, a distal end and an interior lumen therethrough; and a substantially flat external flange coupled to the proximal end, wherein the flange comprises a substantially flat base; a substantially flat cover; and a hinge coupling the cover to the base. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a prior art catheter device. 
     FIG. 2 is a side elevational view of a preferred embodiment catheter of the present invention. 
     FIG. 3 is an end elevational view of the preferred embodiment catheter of the present invention. 
     FIG. 4 is a cross-sectional view of the preferred embodiment catheter of the present invention. 
     FIG. 5 is a side elevational view of a metal stiffener used for inserting the catheter of the present invention into the patient over a wire guide. 
     FIG. 6 is a side elevational view of a second embodiment catheter of the present invention. 
     FIG. 7 is an end elevational view of the second embodiment view catheter of the present invention. 
     FIG. 8 is a partial cross-sectional view of the preferred embodiment catheter of the present invention inserted into a patient&#39;s stomach. 
     FIG. 9 is a partial cross-sectional view of the second embodiment catheter of the present invention inserted into a patient&#39;s stomach. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
     The indwelling catheter of the present invention solves the problems associated with the prior art feeding catheters by providing an extremely low profile proximal section which is situated external to the patient&#39;s body when the catheter is in place. The external portion is preferably in the form of a “trap door”, including a flat base portion that lies against the patient&#39;s skin and a flat, hinged cover which is operative to seal the proximal opening of the catheter when not in use. In order to retain the catheter and prevent it from being accidentally dislodged, the catheter includes a series of helical loops which are unformed during catheter insertion and then automatically reform in order to hold the catheter in place internally. The catheter is self-adjusting in that fewer or greater loops will automatically reform depending upon the thickness of the patient&#39;s abdominal wall. The catheter of the present invention is therefore self-adjusting in order to accommodate the distance between the abdominal wall and the stomach. 
     Referring now to FIG. 2, there is illustrated a preferred embodiment of the indwelling catheter of the present invention, indicated generally at  100 . The catheter  100  comprises an elongated tube  102  having an open central lumen  104  (see FIG. 4) extending therethrough. The tube  102  may be made from any flexible, biologically compatible material such as polyurethane. The proximal end of the tube  102  includes an opening  106  (see FIG. 3) which communicates with the lumen  104 . The distal end  108  of the tube  102  is preferably tapered and includes an axially directed end hole  110 . The tube  102  further includes a plurality of side ports  112  within the distal pigtail  114 . The end hole  110  and the side ports  112  provide paths for fluid communication between the interior lumen  104  and the outside of the catheter  100 . 
     The catheter  100  includes a distal pigtail loop  114  so that the internal end of the catheter will be blunt and non-irritating. The catheter  100  further includes several helically wound loops  116  near the proximal end of the catheter  100 . In the preferred embodiment, the catheter has four such loops  116 . A short, substantially straight section  118  of the catheter  100  lies between the helical loops  116  and the proximal end of the catheter. Both the distal pigtail  114  and the helical loops  116  are formed in the catheter  100  such that they will straighten out when a metal stiffener  120  (see FIG. 5) is inserted into the central lumen  104  of the catheter, and will then automatically reform when the metal stiffener  120  is removed from the catheter  100 . 
     Referring to FIG. 3, it can be seen that the helical coils  116  have a central axis  117  about which they are positioned. The remainder of the catheter body  102 , from the proximal section  118  to the distal pigtail  114 , lies substantially within a plane  119 . In the preferred embodiment of the present invention, the central axis  117  of the helical coils  116  is either substantially parallel to the plane  119  or lies substantially within the plane  119 , but is not perpendicular to the plane  119 . 
     A second embodiment of the indwelling catheter of the present invention is illustrated in FIGS. 6 and 7, and indicated generally at  200 . The catheter  200  is identical to the catheter  100 , with the exception that the central axis  202  of the helical coils  116  is formed substantially perpendicular to the plane  204  in which most of the catheter body lies. Operation and placement of the catheter  200  is analogous to the operation and placement of the catheter  100 . 
     The proximal end of the catheter  100  preferably includes a flange  122  that sits substantially flush with the exterior surface of the patient&#39;s skin when the catheter  100  is in place. The flange  122  is designed so as to minimize the amount of the catheter  100  which protrudes away from the patient&#39;s abdominal wall. In a preferred embodiment, the flange  122  comprises a substantially flat base portion  124  which is integrally formed as a single unit with the catheter  100 . The opening  106  into the central lumen  104  passes through the base portion  124 . The base portion  124  is preferably rectangular in shape, having dimensions of 1.5 cm.×2.5 cm.×2 mm. The flange  122  further preferably includes a similarly sized cover  126  which is coupled to the base portion  124  by an integrally formed hinge  128 . The cover  126  includes a protrusion  130  thereon which is placed so as to plug the opening  106  when the cover  126  is mated with the base portion  124 . The diameter of the opening  106  and the diameter of the protrusion  130  are chosen such that they couple in an interference fit, thereby prohibiting fluid leakage from the catheter  100  when the cover  126  is in place. The base  124  further includes a tab  132  and the cover  126  includes a complimentary tab  134  in order to facilitate separation of the cover  126  from the base  124 . 
     A preferred use for the indwelling catheter  100  of the present invention is for access to the gastrointestinal tract from outside of a patient, although those skilled in the art will recognize the use of the present invention for access to other body cavities is analogous. When used as a gastrojejunostomy catheter, the catheter  100  preferably has an overall length of 32 cm. with all of the coils  116  reformed and the distal pigtail  114  reformed. The distance from the base  124  of the flange  122  to the first of the helical loops  116  is preferably in the range of 0.5-3 cm. The distance from the most distal of the helical coils  116  to the distal end of the catheter  100  is preferably 27 cm., but can be sized differently according to the size of the patient. In this configuration, the catheter  100  is long enough such that its distal end can be positioned in the jejenum and feeding through the catheter can bypass the stomach. In order to use the catheter  100  as a gastrostomy catheter, it is only necessary that the distance between the helical coils  116  and the distal end be removed, allowing the catheter  100  to be used for feeding directly into the stomach. The catheter  100  is further particularly adapted for use as a cecostomy catheter for providing access to the cecum. The catheter for such gastrointestinal applications is preferably 10 fr. in size, but other sizes may be used depending upon patient size. 
     In order to position the catheter  100  within the patient, the metal stiffening tube  120  is inserted into the proximal opening  106  and pushed all the way to the distal tip  108  of the catheter  100 . This will cause the coils  116  and the distal pigtail  114  to completely straighten out. The catheter  100 , with the metal stiffener  120  in place, may then be inserted over a wire guide through the patient&#39;s abdominal wall and positioned under fluoroscopic control until the distal end is at the desired location within the patient. At this point, the base  124  of the flange  122  will be flush against the exterior surface of the patient&#39;s abdominal wall. The metal stiffener  120  and the wire guide are then removed from the catheter, allowing the distal pigtail  114  to reform and further allowing one or more of the helical coils  116  to reform. 
     The catheter  100  is illustrated in FIG. 6 as being placed through the abdominal wall  140  and stomach  142  of a patient. The illustration shows the catheter  100  after the metal stiffening tube  120  has been removed therefrom. It can be seen from this illustration that upon removal of the metal stiffening tube  120 , only two of the four original helical coils  116  have reformed in the catheter. This is because the thickness of the abdominal wall  140  is such that the remaining two helical coils  116  must remain unwound in order for the catheter  100  to traverse the distance between the exterior surface  144  of the abdominal wall  140  to the interior surface  146  of the stomach  142 . Therefore, by placing a plurality of helical loops  116  in the catheter  100 , the catheter is made substantially universal in terms of patient size. Depending upon the thickness of the abdominal wall  140 , a greater or lesser number of the loops  116  will reform within the stomach. For a small patient, all of the helical loops  116  will reform in the stomach, while for a larger patient, only a few of the loops  116  will reform. The result is that the catheter  100  adjusts itself to accommodate the distance between the exterior abdominal wall  144  and the interior of the stomach  146 . The reforming of the helical loops  116  within the stomach  142  act to retain tension between the base  124  in order to hold it securely in place at the surface  144 . It will be appreciated by those skilled in the art that although the catheter  100  was illustrated in the preferred embodiment as having four helical loops  116 , the present invention comprehends the catheter having a greater or lesser number of helical loops  116 . 
     It will be appreciated with reference to FIG. 6 that once the catheter  100  has been positioned, the only portion of the catheter  100  which remains external to the patient is set flush with the patient&#39;s skin so that there is nothing protruding away from the patient&#39;s abdominal wall. This is psychologically beneficial for the patient, plus it minimizes the chance of pediatric patients being able to grasp the proximal end of the catheter and pull it out. As an additional precaution, the entire proximal end of the catheter can be covered and kept out of sight by placing a small bandage thereover when not in use. As a further precaution, a piece of hypoallergenic two-sided tape (such as DUODERM) may be placed between the base portion  124  and the patient&#39;s skin. 
     FIG. 7 illustrates the second embodiment catheter  200  inserted into a patient&#39;s stomach in a manner analagous that of FIG.  6 . It can be seen that at least one of the helical coils  116  have reformed, thereby securing the catheter  200  in place. 
     When the catheter  100  is not in use, the cover  126  is kept in place on the base  124 , sealing the proximal opening  106 . When it is desired to introduce fluids into the body through the catheter  100 , the cover  126  is lifted, thereby exposing the proximal opening  106 . The catheter may then be accessed with, for example, a 14 gauge blunt tipped needle or a 14 gauge plastic cannula. 
     An additional feature of the present invention is that patient&#39;s frequently have several long term indwelling catheters in place for different purposes. Some may be for infusion of chemotherapeutic drugs and others may be for feeding. In such situations, there is a very real danger of confusing which catheter is for which purpose, making it possible to inject feed into the venous system or chemotherapy drugs into the stomach, both of which can be a potentially fatal mistake. If the catheter  100  of the present invention is used for feeding, its exterior flange  122  is unlike any other indwelling catheter that the patient is likely to have inserted, therefore the likelihood of a parent or night shift nurse-aide connecting to the wrong catheter is greatly reduced or even eliminated. Furthermore, if more than one of the catheters of the present invention are being used in the same patient for different purposes, the cover  126  provides a convenient surface for labelling the catheter in order to minimize confusion as to its purpose. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. For example, the preferred embodiment catheter has been described for use in the gastrointestinal tract, however it may be used in any procedure where it is desired to maintain continuing access from the exterior of a patient to an internal body cavity.