Catheter for nasogastric intubation

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.

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'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.

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', 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.