Abstract:
This invention provides a catheter for nasogastric intubation comprises a tube for nasogastric intubation and a plastic separator, said tube for nasogastric intubation consisting of a catheter and a plastic sheath tube having a longitudinal tear-off line over full length thereof together with elasticity and rigidity slightly larger than those of said catheter inserted slidably thereinto, and said separator for splitting said sheath tube fixing said tube at the vicinity of a nostril.

Description:
This is a continuation of co-pending application Ser. No. 933,642 filed on Nov. 21, 1986, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a catheter for nasogastric intubation. 
     2. Description of the Prior Art 
     Normally, a catheter for nasogastric intubation to be used for nutritional purposes comprises a weighted portion in which a weight is sealed into a distal end of a soft small-diameter plastic tube. The weighted portion is inserted through nostril into the esophagus and into the stomach or the intestines the weight facilitating catheter placement for supply of a nutritious liquid through one or two side holes positioned slightly above the weighted portion. 
     Since the catheter remains positioned in and through the nostril for a long period of time, a patient may feel considerable pain. To avoid such pain, the catheter is preferably formed of a material as soft as possible. Moreover, since the catheter remains in contact with the walls of the internal organs for a long period of time, if the catheter is formed of a hard material, the tissue of the walls of the internal organs may be injured. 
     Also, for this reason, it is desired that the catheter be formed from a soft plastic tube. However, and such tube has to be inserted into the stomach and intestines following a torvous path nostril, through the the narrow-passage larynx and the esophagus and therefor a catheter made of a soft plastic tube lacks the requisite stiffness and is difficult to insert. 
     In the past, therefore, a method has been employed in which a guide wire is inserted into the boil of the catheter to increase the catheter stiffness. In this proposal, however, insertion of the guide wire into the catheter a lubricant be used to coat the internal surfaces of the bore of the catheter to decrease the frictional resistance therebetween. Such procedure is unnecessarily time consuming, and in addition, insertion of the guide wire is cumbersome. Furthermore, such procedure may result in profiction the end of the guide wire through one of the side holes of the catheter where it may pierce the walls of the internal organs. 
     SUMMARY OF THE INVENTION 
     This invention overcomes the disadvantages noted above. According to the present invention, a catheter is inserted and encased into a plastic insertion guide or sheath tube having a longitudinal tear-off line over the full length and there of having elasticity and rigidity slightly greater than those of the catheter. The catheter and encasing sheath tube are inserted together through the patient&#39;s nostril, larynx and esophagus into the stomach or intestines. A separator positioned just outside the nostril splits the sheath tube and holds the catheter as the sheath tube is withdrawn from around the intubated catheter. The separator includes an inner tube projecting into the bore of an outer tube of the separator. The catheter extends within and through the inner tube, and the separator is positioned along the catheter near the nostril. The sheath tube is extended over the end, and around the outside of, the inner tube, and is then split along the tear-off line as the sheath tube is pulled from around the inner tube and out through an opening in the side of the outer tube of the separator. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the catheter, sheath tube and separator according to this invention, showing the position of the sheath and catheter in the separator during sheath withdrawal. 
     FIG. 2 is an axial section view of the catheter, sheath tube and separator shown in FIG. 1. 
     FIG. 3 is a perspective view of the spearator. 
     FIG. 4 is a section view taken along line X--X of FIG. 3. 
     FIG. 5 is a section view of the separator taken along line Y--Y of FIG. 3. 
     FIG. 6 is a plan view of the catheter and sheath tube without the separator. 
     FIG. 7 is an enlarged plan view of the distal end of the catheter and sheath tube shown in FIG. 6. 
     FIG. 8 is a section view of a second embodiment of the separator taken along substantially the same lines as the section view of FIG. 4. 
     FIG. 9 is a section view of a third embodiment of the separator taken along substantially the same lines as the section view of FIG. 4. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, catheter 1 is made of a soft plastic. As described above, sheath tube 2 is a plastic tube having elasticity and rigidity slightly greater than those of the catheter, and is preferably provided with a longitudinal tar-off line 3 over substantially the full length of the sheath tube. The tear-off line 3 is preferably formed by integrating a line material dissimilar to and weaker than the material of which the sheath tube 2 is made, longitudinally along one side of the sheath tube. Alternatively, the tear-off line 3 may be formed by decreasing the wall thickness of the sheath tube 2 longitudinally along one side of the sheath tube 2. It will be understood that although only a single tear-off lines is shown in the drawings, there may be more than one such longitudinal tear-off line. However, it is desirable that the tear-off line does not extend through a very small area 10 at the distal end of the catheter. 
     A separator for holding the catheter is made of slightly hard plastics, and is set near the nostril. The separator includes an inner tube 4 having an inner bore of the separator sufficient in diameter to slidably receive the catheter 1 therein, and an outer tube 5 having a bore of sufficient diameter to slidably accept the sheath tube therein. The outer tube 5 is positioned coaxially with the inner tube 4, the bore of the outer tube being sufficient to form an annulus between the outside surface of the inner tube and the bore of the outer tube 5. The separator is provided with a closed portion 6 which occludes a portion of the annulus between both tubes 4 and 5. The bore of the inner tube 4 extends through the closed portion 6 to a back end of the inner tube 4, while a front end of the inner tube extends within the bore of the outer tube toward, but not to, an open end of the outer tube 5. Further, a portion of the outer tube 5 is cut out to form a side opening 9 positioned longitudinally between the closed portion 6 and the front end of the inner tube 4. As shown in the drawings, the closed portion 6 has an axially or longitudinally inclining face 8, and the side opening 9 in the outer tube 5 has an oppositely inclined face portion 7 opposite the closed portion 6 and inclining face 8. 
     Although for ease of removal of the sheath tube 2 the tear-off line 3 is disclosed herein as being formed in the sheath tube prior to use and withdrawal of the sheath tube 2 after intubation, it is also possible with the present invention to use a sheath tube 2 having no tear-off line 3, that is withdrawn from around the catheter by longitudinally splitting one side of the sheath tube 2 with a cutter (not shown), mounted or formed in the separator near the inner tubes opposite the side opening as the sheath tube 2 is pulled out through the side opening 9 of the separator. 
     The separator is installed on the catheter 4 and sheath tube 2 by inserting the catheter 1 into the inner tube 4 while slightly splitting the sheath tube and positioning the split end of the sheath tube 2 within the annulus between the tubes 4 and 5. The sheath tube 2 is then pulled through the opening 9 in the tube 5, and while catheter 1 is pulled through the inner tube 4, in directions shown by the arrows in FIGS. 1 and 2. Once the separator is positioned near the nostril and the catheter 1 is satisfactorily emplaced, the sheath tube 2 is continuously drawn out upward from the side opening 9, splitting the tube 2 at eh tear-off line 3 responsive to pullin the sheath tube 2 against the inner tube 4 until the sheath tube 2 is entirely drawn out, thereby leaving the catheter 1 intubated in the stomach and the intestines. 
     The features of the separator shown in FIGS. 1 and 2 and described above may also be seen in FIGS. 3, 4 and 5, showing the separator without the catheter 1 and sheath tube 2. The separator closed protion 6, outer tube 5, and inner tube combine to form the body of the separator. 
     The catheter 1 is shown in FIG. 6, wherein the letter A designates a weight portion at a distal end of the catheter 1, the letter B designates side holes from which a nutritous liquid is supplied into the stomach or intestines from the distal end of the catheter 1, and the letter C designates a securing portion at a proximal end of the catheter 1 for connecting the catheter to a bottle of nutritional liquid. The enlarged view of the distal end of the catheter 1 shown in FIG. 7 clearly shows sheath tube 2, the tear-off line of the sheath tube 2, and the non-tearing portion 10 thereof. 
     FIG. 8 shows a second example of a separator according to this invention, wherein an axially extending slit 11 is provided through the outer tube 5, the closed portion 6, and the inner tube 4, to the center or axis of the separator. 
     A third embodiment of a separator according to this invention is shown in FIG. 9, wherein the separator is longitudinally divided into two parts. Inserting projections 12 and inserted holes 12&#39;, adapt the two parts of the separator to be removably integrated to each other. The separator is installed on the catheter 1/sheath tube 2 combination by separating the two parts, and then integrating the parts to form the separator with the catheter 1 and sheath tube 2 appropriately positioned therein. 
     In the operation of this invention, the catheter 1 is encased in the sheath tube 2, and the combination is inserted into the interal organs as mentioned above. After intubation, the sheath tube 2 can be smoothly and easily drawn up from the interal organs by splitting the sheath tube 2 with the inner tube, or splitting means on the separator for splitting the sheath tube 2 responsive to withdrawal of the sheath tube from around the inner tube 4. 
     Further by setting this separator at the nostril, the operation can be performed by a single person as compared with two persons in a conventional method. Since the sheath tube has slightly greater elasticity and rigidity than that of the catheter, the insertion into the stomach and the intestines thereof can be performed very easily and rapidly. Since the drawn out sheath tube can be performed smoothly and promptly, a patient feels minimal discomfort. The sheath tube and the separator can be produced at low cost because they can be easily formed out of plastic.