Self Propelled Catheter

Abstract

A catheter effective for self movement within a passageway comprises an elongated tube having a first channel extending axially thereof and a member operatively hingedly connected to the forward end of the tube. The member is provided with means such as a plurality of angularly projecting parts for gripping the walls of the passageway. Means are provided to oscillate the member within the passageway so that the projecting parts alternately grip one side wall of the passageway and then another. The oscillating means preferably comprises a fluid system which includes two channels connecting with the channel of the elongated tube, extending forwardly and outwardly therefrom, and provided with openings proximate the oscillating member. When a fluid is forced through the main channel it is directed by fluid control means to enter one and then the other of the laterally extending channels to pressurize different surface parts of the member, thereby to cause the oscillation thereof.

Description

This invention relates generally to medical devices, and more specifically to a self propelled catheter.

Catheters are employed in a wide variety of applications for medical purposes. A catheter is generally defined as an elongated tube which is inserted into a body cavity for the purposes of injecting or withdrawing fluids or other materials. Usually such a device is manually inserted into an opening in the body, and carefully forced into the proper area of the body. Such a procedure is often accompanied by discomfort and even pain, and a number of attempts have been made to ease the difficulty accompanying the insertion of such a device.

One important application for such a device is to clear an intestinal obstruction. Generally the elimination of such an obstruction involves decompression of the distended intestinal tract by aspiration of liquid and gas through a catheter. Passage of the catheter from the stomach through the pyloric sphinctor into the duodenum and the small intestine is usually difficult. Generally, fluoroscopy is required for accurate placement of the tube at the pyloric canal where the obstruction is generally found. Many techniques and devices have been developed to assist the passage of a catheter into the duodenum. Tubes having weighted front ends are currently employed for this purpose. Electromagnets and remotely guided mechanical devices have also been used, but without much success.

One of the primary difficulties thus far experienced in devices of this type is that the catheter, in order to negotiate the tortuous body passages involved, must be composed of a material which is soft and flexible. This requirement in turn causes the advancement of such a device through a body passage and particularly the narrow outlet of the stomach to be especially difficult, primarily because the front end of the device may be impeded in its advance, as by the coarse folds of the mucosal lining of the stomach. In addition, the remaining portion of the tube often winds about itself in the distended stomach portion and is difficult to remove without injury.

While self propelled devices have been developed to avoid these difficulties, their complexity and the associated equipment required renders such devices generally disadvantageous to manufacture and employ. Furthermore, they are generally too large for most applications of the number of moving parts which are required to operate the device.

It is the primary object of this invention therefore to provide a catheter which is characterized by its simplicity of structure, low cost, and ease of manipulation.

It is another object of this invention to provide a catheter which is characterized by a self propulsion system which enables the catheter to advance under its own power along the walls of the passageway with a minimum of moving parts.

Broadly, the objects of the invention are achieved by a catheter which is effective for self movement within a passageway and which comprises an elongated tube having a first channel extending axially therein, a member operatively hingedly connected to the forward end of the tube, means operatively connected to the member and effective to grip the walls of the passageway as the member advances therethrough, and means operatively connected to the tube and effective to oscillate the member, thus causing the gripping means alternately to engage the opposite walls of the passageway, thereby to advance the tube along the passageway. In the preferred embodiment a fluid is caused to flow through the first channel in the tube and to pressurize the member at one part of a surface and then another part in accordance with a fluid flow path which is controlled by a fluid control means operatively connected to the tube. The flow path is defined by second and third channels in the tube which communicate with the first channel and extend forwardly and outwardly toward the member. Each of the second and third channels is provided with an opening in registration with the member. The openings are laterally spaced from each other and proximate to different surface parts of the member.

In order to ensure a continuous flow of fluid through the catheter a second tube is provided. This second tube communicates with the forward opening in the second and third channels and is effective to draw the fluid from these openings out of the catheter. Thus, fluid is passed down into the catheter, enters the first channel, diverges to either of the second or third channels, egresses from the openings at the end of the channel to which it is diverted, and then is drawn through the second tube for passage out of the system or for recirculation within the first channel.

When the catheter is to be employed as a self propelled intestinal tube such as for the elimination of blockages in the stomach area, a plurality of holes are placed in the outer surface of the elongated tube and connect with the first channel. Thus, after the catheter has oscillated down the passageway to the blockage in the stomach area, a reverse flow of fluid is effected by providing a suction pressure on the first channel, thereby to suck the stomach obstructions, for example, through the holes in the tube surface. The second tube may be open to the atmosphere at this time to serve as an air vent.

The divergence of the stream of fluid passing through the first channel of the catheter to one or the other of the laterally extending channels connecting with the first channel occurs in accordance with known fluid flow principles. It is known, for example, that a low pressure region is formed near a wall by molecules from a jet stream which sweep other molecules out of a region between the wall and the jet stream. The jet stream is therefore said to entrain fluid on both sides. Because of the presence of the walls, some of the molecules are evacuated between the jet and each wall thereby causing the low pressure region into which there is a counter flow of fluid along the wall. Because of the turbulent fluctuations, the jet stream will momentarily bend or deflect toward one of the walls in the passageway. This tends to reduce the counter flow, thereby lowering the pressure between the jet stream and that wall to a greater extent than between the jet stream and the opposite wall. The jet stream therefore is quickly attracted to the wall to which it is deflected. Initially, the jet stream will randomly orient itself to either of the opposite walls defining the passageway through which it passes.

It has been determined that the jet stream can be shifted by the use of certain controls. For example, if openings are provided in the opposite walls of the channel through which the jet stream passes, they may be employed as controls to direct the stream to one wall or another. For example, if one of the openings is blocked or constructed, the pressure on that wall at that opening will be lower than on the opposite wall at the unrestricted opening. As a result, the jet stream will deflect toward the lower pressure region. Additional control can be provided by supplying an external pressure to either of the openings so that a greater differential pressure between the openings will be placed upon the jet stream passing therebetween. If the low pressure region is alternated between openings the jet stream will be alternately deflected to one or to the other side of the channel.

This principle of fluid flow control is employed in the present invention to provide the fluid control means which acts on the fluid in the catheter. The fluid control means is effective to direct the passage of fluid from the first channel to one and then the other of the second and third channels. Automatic and continuous direction and control of the passing fluid is achieved by providing first and second control tubes within the catheter which extend from the openings in the second and third channels rearward to communicate with the first channel on opposite sides thereof. As the fluid passes these control tubes in the first catheter channel it is directed to either the second or third channels by a controlling pressure at the orifice of the control tubes. These control tubes are positioned on opposite sides of the main stream of fluid flow so that a difference in pressure at the orifices in the control tubes will cause a divergence of the fluid toward the area of lowest pressure.

Each of the control tubes is provided with an orifice proximate to a part of the oscillating member. These orifices are alternately closed or constructed by the movement of the member from one position to another during its oscillation. As a result, the control tube having the blocked orifice experiences a reduction in pressure which is transmitted to that portion of the tube which connects directly with the first channel. The passing fluid stream is therefore attracted to the control tube having reduction in pressure and is thereby diverted to the channel closest to that control tube. Upon passing through that channel the fluid stream pressurizes the member to again shift positions and the opposite tube is there constricted. As a result, the control tube having the blocked orifice experiences a reduction in pressure which is transmitted to that portion of the tube which connects directly with the first channel. The passing fluid stream is therefore attracted to the control tube having reduction in pressure and is thereby diverted to the channel closest to that control tube. Upon passing through that channel the fluid stream pressurizes the member to again shift positions and the opposite tube is therefore constricted. As a result, the fluid stream is diverted back to its original position and passes through the other of the channels. The cycle is continued until the oscillating member strikes an impenetrable object or until the fluid is no longer passed through the catheter. Additional control is provided by having the orifices at the forward end of the control tubes communicate with the openings in the second and third channels which are also proximate the oscillating member. With this construction, the pressure formed at the output end of the channel through which the fluid passes is sufficient to shift the member, and also to increase the pressure at the orifice of the control tube with which it is in communication. Thus, the pressure of that control tube increases and the increase is transmitted to the orifice of that tube positioned at the intersection with the fluid stream in the first channel. This then provides a positive force on the fluid stream in the first channel to supplement the reduction in pressure at the opposite control tube due to the simultaneous blockage of its orifice by the member.

To the accomplishment of the foregoing, and to such other objects as may hereinafter appear, the present invention is directed to a self propelled catheter as defined in the appended claims, and as described in the following drawings wherein:

FIG. 1 is a pictorial view of a catheter embodying the principles of the invention;

FIG. 2 is an enlarged fragmentary perspective view of a portion of the catheter illustrated in FIG. 1;

FIG. 3 is a cross sectional view taken on line 3--3 of FIG. 2;

FIG. 4 is a fragmentary cross sectional view taken on line 4--4 of FIG. 3; and

FIGS. 5 through 11 are cross sectional views taken respectively along the lines 5--5, 6--6, 7--7, 8--8, 9--9, 10--10 and 11--11 of FIG. 3.

Referring now to the drawings and specifically FIGS. 1 through 4, a catheter generally designated 10 comprises an elongated tube 12 having an opening 14 at one end and attached to an extended tip member 16 at the other end. A second tube 18 communicates with an interior chamber 19 of the tube 12 at the joint 20 and extends substantially parallel to the tube 12 along its length. The tubes 12 and 18 may be joined together at several points 21 by any suitable bonding method in order that they be held in close contact during the operation of the device. The second tube 18 is also provided with an opening 22 at its rearward end for the purpose of inserting and withdrawing fluids.

The tube 12 is assembled in two parts 24 and 26. The part 24 contains the interior chamber 19 and carries the tip member 16. The part 26 is provided with a plurality of holes 28 positioned circumferentially about the outer surface of the tube 12 below the interior chamber 19 and connecting with the interior passage 40. These openings 28 are more clearly illustrated in FIG. 2, and are employed for the aspiration of liquids and gases from the interior of the body passageway through which the catheter is employed, for example, as an intestinal tube for the elimination of an obstruction in the stomach.

As illustrated in FIG. 2, the member 16 is provided with a plurality of rearwardly and outwardly angular projecting parts 30 which are effective to grip the walls of the passageway into which the catheter 10 is inserted. The member 16 is operatively connected to the tube 12 by means of the flexible collar 32. This collar 32 is composed of a material such as rubber which is soft and flexible so as to permit lateral oscillatory movement of the member 16. The member 16 at its lower end is provided with a pair of laterally spaced downwardly facing surfaces 60 and 62.

The means for oscillating the member 16 from side to side as it passes through a passageway may best be explained with reference to the fluid control system illustrated in FIGS. 2 through 11, As shown in FIGS. 2 and 3, the interior section of the tube 12 is provided with a plurality of channels 34, 36 and 38. The first channel 34 communicates directly with the main passage 40 in tube part 26 through a construction 42, and as it extends upwardly it diverges into channels 36 and 38, the latter terminating at openings 56 and 58 respectively which are located respectively opposite the surfaces 60 and 62 of member 16. As shown best in FIGS. 2, 10 and 11, the interior chamber 19 is defined at the front portion of the catheter by the member 16, at the rear portion by the widest segment 43 of tapered tube section 45 and at the upper and lower portions by the inner surface of tube 12. This chamber 19 communicates directly with the interior of tube 18 (FIG. 10) and with the openings 56 and 58 an channels 36 and 38. A triangularly shaped splitter 64 has its vertex 66 positioned at the junction of channels 34, 36 and 38. This splitter 64 provides an effective partition between the channels 36 and 38 and aids in the direction of the fluid into and through one or the other of the channels 36 and 38. This splitter is also clearly shown in FIG. 4. Positioned to either side of the channels 34, 36, 38 are control tubes 44 and 46. These control tubes 44 and 46 are provided with openings 48 and 50 at one end which communicate directly with the channel 34. The tubes 44 and 46 terminate at their own ends in openings 52 and 54. These openings 52 and 54 communicate with the openings 56 and 58 in the channels 36 and 38 respectively, and are also located respectively opposite the member surfaces 60 and 62.

In the operation of the catheter 10 a fluid is forced through the opening 14 in the tube 12, and into the main passage 40 in the direction of the arrow 68 of FIG. 3. The fluid is then caused to flow through the construction 42 into the channel 34. As explained above, when the fluid passes through the constriction 42 and effectively becomes a jet stream due to the increase in velocity, it will inherently seek one of the opposite walls 70 and 72 which define the various channels within the tube 12. For illustrative purposes, the fluid is indicated by means of several arrows as seeking to attach to the wall 70. Thus, the fluid flows into the channel 36 and out of the opening 56. Suction pressure applied through the opening 22 in the tube 18 is effective to draw the fluid from the opening 56 out of the tube 12 through chamber 19 and into the tube 18.

The passage of the fluid through the opening 56 has several effects. First it causes a pressure at the surface 60 of member 16 sufficient to shift the member 16 to the position shown in FIG. 3. In addition, surface 60 no longer blocks the orifice 52 of the control tube 44 and the pressure at present at the orifice 50 of the tube 44 is increased. The effect of this increased pressure is to cause the fluid continuously flowing through the channel 34 to be deflected to the opposite wall 72. Additional assurance of this deflection is achieved because of the shifting of the member 16 to the position shown in FIG. 3. In the position shown, the surface 58 constricts the space 74 between the surface 62 and the openings 54 and 58. The result of this construction is a reduction in the pressure present at the orifice 48 of tube 46. This reduced pressure attracts the fluid stream into the wall 72 as it passes through the nozzle 42 into the channel 34. Thus, the fluid is directed into the channel 38 and reverses the cycle above described. That is, the member 16 is caused to again shift by the fluid passing out of the opening 58. The pressure of the fluid is effectively applied to the surface 62 of the member 16 causing the hingedly mounted member 16 to shift to the opposite position. Consequently, the pressure increases at the opening 48 of the tube 46 and simultaneously decreases at the opening 50 of tube 44 due to the construction of the space 76 proximate the openings 52 and 56. The fluid stream is therefore deflected back to channel 36.

Continued passage of fluid into the tube 12 causes automatic oscillation of the member 16. The oscillation will continue until the member 16 reaches an impenetrable obstacle or until the forcing of fluid into the channel 40 is discontinued. The smooth step by step advance of the catheter 12 is achieved by the gripping action of the parts 30 as the member 16 is oscillated. These parts seize the passageway wall such as the lining of the stomach and lightly press against this lining to pull the entire tube forward. Upon the shifting of the member 16 to the opposite position the parts contact the opposite wall and continue to pull the tube forward. For this purpose the parts are composed of a firm but soft and flexible plastic rubber or the like. A suitable material is polyvinyl plastic. Obviously the tips of parts 30 should not be so sharp as to inflict injury upon sensitive areas such as that of the stomach wall or other internal cavity of the body.

FIGS. 5 through 11 illustrate by means of cross sectional views the interior configuration of the tube 12. As noted in FIG. 5 the channels 36 and 38 are substantially rectangular in cross section while the control tubes 44 and 46 are generally circular in cross section. The cross sectional areas of the tubes 44 and 46 are preferably small relative to those of the channels 36 and 38. The fluid control is effected by the tubes because of the ability to vary the pressure at the several tube openings and this in turn is due in part to the relative constricted size of the tubes. As noted also in FIG. 5, the channels 36 and 38 are laterally spaced from each other proximate the member 16 so that they might be in registration with separated parts of the member 16, i.e., surfaces 60 and 62. The lateral displacement ensures that the pressure provided at these openings will be sufficient to shift the member from one position to another.

It will be noted in FIGS. 6 and 7 that the channels 36 and 38 converge rearwardly of member 16 and eventually communicate with and merge into the channel 34. The control tubes 44 and 46 are generally parallel to each other and extend substantially parallel to the longitudinal axis of the tube 12. These tubes are provided with laterally extending arms 78 and 80 shown in FIG. 8. The arms 78 and 80 intersect the channel 34 proximate the constriction 42 at a position such as to impress a force on the passing fluid stream in a direction substantially perpendicular to its direction of movement. The stream is therefore readily diverted in the direction of applied pressure. As illustrated in FIG. 9 the control tubes 44 and 46 do not extend beyond the initial opening in the construction 42.

FIG. 10 indicates the intersection of the suction tube 18 and the chamber 19 in tube 12. As above indicated the tube 18 is employed during the operation of the system to withdraw fluid from the openings 56 and 58 in channels 36 and 38 to thereby complete the flow of the fluid through the system. The suction pressure provided in this tube 18 such as by suitable conventional pumping means (not shown) operatively connected to opening 22 is effective to draw substantially all of the fluid flowing through main passage 40 into tube 12. The fluid in passage 40 therefore does not escape through openings 28 as the catheter 10 oscillates through an internal body cavity since the pressure in the body cavity is greater than that provided in tube 18. When the advance of the catheter through a body cavity is terminated, the tube 18 may be open to the atmosphere and a suction pressure applied to the passage 40 through opening 14 in tube 12 and aspiration of fluids from the body cavity through openings 28 may thereby be effected.

FIG. 11 further illustrates that the main channel 40 forms a substantial part of the interior of the tube 12 rearwardly of the constriction 42. This illustration also indicates that the tube 18 extends longitudinally of the tube 12 along the outer surface thereof. It is apparent that the catheter may be modified to incorporate the passageway of the tube 18 within the interior section of the tube 12 instead of by means of an outer tube.

It will be appreciated that the catheter of the invention is simple to manufacture, inexpensive, and efficient in operation. No moving parts other than the oscillating tip are required, and the passage of the catheter into a body cavity is achieved without adverse effects on the patient.

While only one embodiment has been described, a wide variety of modifications may be made, all within the scope of the invention.

Claims

I claim:

1. A catheter effective for movement within a passageway defined by a plurality of walls comprising a catheter tube, a member operatively hingedly connected to the forward end of said tube for side-to-side oscillation, means operatively connected to said member and effective to grip the walls of the passageway as said member advances therethrough, and means operatively connected to said tube and effective to oscillate said member from side to side, whereby said gripping means alternately engages the opposite walls of the passageway, thereby to advance said tube along said passageway, said tube having a channel extending axially thereof and communicating with said member, said channel being adapted to receive and pass a fluid toward said member, and means operatively connected to said channel and effective to oscillate said member in response to the flow of fluid through said channel.

2. In the catheter of claim 1, said tube having second and third channels communicating with said first channel and extending toward said member, each of said second and third channels having an opening in registration with said member, said openings being laterally spaced from each other and proximate to different surface parts of said member, and fluid control means operatively connected to said first channel and effective to direct a fluid passing through said first channel alternately to one and then the other of said second and third channels, thereby to cause said fluid to pass through one and then the other of said openings in said channels, whereby said member is caused to oscillate.

3. In the catheter of claim 2, a second tube operatively connected catheter tube, said second tube being in communication with the openings in said second and third channels and being effective to draw a fluid from said openings after the fluid passes through said channels.

4. The catheter of claim 2, in which said fluid control means comprises a first control tube having first and second orifices and a passageway therebetween, said first orifice being positioned in registration with and proximate to one of said surface parts on said member and said second orifice connecting with said first channel in a position to direct a fluid in said first channel toward (a) said second or (b) said third channel in response to (a) the substantial constriction of said first orifice when said surface part is in a first position and (b) the substantial opening of said orifice when said surface part is in a second position.

5. In the catheter of claim 4, a second control tube having first and second orifices and a passageway therebetween, said first orifice of said second control tube being positioned in registration with and proximate to the other of said surface parts of said member, and said second orifice of said second control tube connecting with said first channel opposite to said second orifice of said first control tube and in a position to direct a fluid in said first channel toward (a) said third and (b) said second channel in response to the (a) construction and (b) opening of said first orifice of said second tube by said other surface part when said member oscillates.

6. The catheter of claim 5, in which said first and second control tubes have parts extending axially of said first tube and parts extending laterally of said tube, said lateral parts terminating at said second orifices.

7. In the catheter of claim 6, a constricted nozzle at a part of said first channel positioned rearwardly of said second and third channels, said second orifices of said first and second control tubes being positioned proximate said nozzle.

8. The catheter of claim 3, in which said fluid control means comprises a first control tube having first and second orifices and a passageway therebetween, said first orifice being positioned in registration with and proximate to one of said surface parts on said member and said second orifice connecting with said first channel in a position to direct a fluid in said first channel toward (a) said second or (b) said third channel in response to (a) the substantial construction of said first orifice when said surface part is in a first position and (b) the substantial opening of said orifice when said surface part is in a second position.

9. In the catheter of claim 8, a second control tube having first and second orifices and a passageway therebetween, said first orifice of said second control tube being positioned in registration with and proximate to the other of said surface parts of said member, and said second orifice of said second control tube connecting with said first channel opposite to said second orifice of said first control tube and in a position to direct a fluid in said first channel toward (a) said third and (b) said second channel in response to the (a) constriction and (b) opening of said first orifice of said second tube by said other surface part when said member oscillates.

10. The catheter of claim 9, in which said first and second control tubes have parts extending axially of said first tube and parts extending laterally of said tube, said lateral parts terminating at said second orifices.

11. In the catheter of claim 10, a constricted nozzle at a part of said first channel positioned rearwardly of said second and third channels, said second orifices of said first and second control tubes being positioned proximate said nozzle.

12. The catheter of claim 11, in which said means for gripping the walls of said passageway comprise a plurality of projecting parts operatively connected to the outer surface of said member.

13. In the catheter of claim 11, a flexible collar operatively connected between said member and said catheter tube.

14. The catheter of claim 11, in which said catheter tube is provided with a plurality of openings for drainage of material from the passageway into which said catheter advances.

15. In the catheter of claim 7, a flexible collar operatively connected between said member and said catheter tube.