Abstract:
A catheter includes a catheter tube, internal and external retention bolsters and a retractable catheter tip. The retractable tip is in the form of a bolus which is extended to axial alignment with the tube for insertion. After insertion with a stylet or the like, removal of the stylet permits the tip to retract automatically and assume a position perpendicular to the axis with minimal protrusion into the corporeal space involved.

Description:
RELATED APPLICATION 
     This application is based on provisional application Ser. No. 60/647,254, filed Jan. 26, 2005, and claims priority therefrom. The provisional application is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to catheters for introducing fluids to body cavities and/or exhausting fluids from body cavities. It relates particularly to what are commonly referred to as balloon catheters, which find particularly advantageous application in aspirating or draining fluid from the stomach or bladder. The invention applies to catheters employing pre-formed, thick-walled balloons or thin walled balloons requiring stretching to their final shape by the instillation of liquid or air. 
     BACKGROUND OF THE INVENTION 
     Whether employed in bladder draining, as with the Foley catheter, or enteral feeding applications, catheters must perform desired functions without becoming occluded or damaging the organ walls, if that is possible. Unfortunately, it is frequently not possible for extended periods of time with conventional catheters. Foley urologic tips and enteral percuteneous replacement catheters all employ tips with side ports. The tips extend as a length of tubing from the base of the catheter retention balloon. The tips poke into the mucosa of the bladder or stomach causing pressure necrosis. In some instances they actually penetrate the organ wall which results in leakage of fluid and subsequent infection. Conventional tips are also subject to restriction of flow in the aspiration mode because the side ports are sucked into the vessel wall mucosa, thereby occluding flow. This “sucking” phenomenon also results in suction sores at the point of contact, resulting in focal points for infection. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a new and improved catheter. 
     Another object is to provide a new and improved catheter including a catheter tube, a retention bolster and a retracting bolus tip. 
     Another object is to provide a catheter including an automatically retracting bolus tip that, in use, does not protrude into a corporeal space to the extent that it can cause necrosis and subsequent erosion of the cavity wall. 
     Still another object is to provide a catheter of the aforedescribed character with a bolus tip which facilitates simple insertion with a stylet and, upon withdrawal of the stylet, the bolus automatically retracts. 
     Yet another object is to provide a catheter which, during insertion with a stylet, presents a rounded tip that facilitates insertion and prevents abrasion. 
     A further object is to provide a catheter including a retracting bolus tip that allows aspiration or drainage without suction retention. 
     Yet a further object is to provide a catheter of the aforedescribed character including a bolus tip that effectively prevents occlusion of the catheter port by mucosa. 
     Yet another object of the invention is to provide an external bolster that provides the maximum in a low profile shape. 
     Yet another object of the invention is to provide an external bolster that provides a soft retention surface that spreads retention pressure over its entire surface and reduces soreness and infection at the site of the external stoma. 
     Yet another object of the invention is to provide an external bolster that provides the ability to lift the bolster for cleansing. 
     Yet another object of the invention is to provide an external bolster that provides for a method of presenting a slit valve contained in the external bolster that allows for the inflation/deflation of the internal retention bolster while at the same time not increasing the size of the external bolster. 
     Yet another object of the invention is to provide an external bolster that acts as a “monitor” for the inflation of the internal bolster. 
     Yet another object of the invention is to provide an external bolster that provides for an easy method of deflating the internal bolster. 
     The invention also incorporates an external inflatable retention device that secures the catheter while at the same time presenting soft, but strong retention because it is inflated with air and its round shape spreads the retention pressure over a large area. External bolsters should be “low profile” so that they do not interfere with the patient&#39;s clothing and are inconspicuous. The new external bolster offers a lower profile than any of the existing devices. 
     The device incorporates a unique insertion tip with a preformed inflatable bolster and also a unique external inflatable retention bolster. Both bolsters are in communication with each other and therefore have the same internal air pressures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention, including its construction and method of operation, is illustrated more or less diagrammatically in the following drawings, in which: 
         FIG. 1  is a side elevational view of the distal end of a catheter embodying features of the present invention, showing its bolus tip in a normal retracted position; 
         FIG. 2  is a rear elevational view of the catheter end seen in  FIG. 1 ; 
         FIG. 3  is a front elevational view of the catheter end seen in  FIG. 1 ; 
         FIG. 4  is a top plan view of the catheter end seen in  FIG. 1 ; 
         FIG. 5  is a sectional view taken along line  5 - 5  of  FIG. 3 ; 
         FIG. 6  is a sectional view taken along lines  6 - 6  of  FIG. 1 ; 
         FIG. 7  is a front elevational view of a stylet used in conjunction with the catheter of the invention to introduce the catheter into a body cavity; 
         FIG. 8  is a front elevational view, similar to  FIG. 1 , showing the stylet in the catheter and holding the bolus in its extended position for insertion; 
         FIG. 9  is a front elevational view of the catheter, similar to  FIGS. 1 and 8  showing the retention balloon fully stretched by the stylet for insertion; 
         FIG. 10  is a front elevational view of the catheter, similar to  FIG. 1  showing the retention balloon folded back on itself during removal; 
         FIG. 11  is a side elevational view of the distal end of another catheter as shown in  FIG. 1 , but with a lower elevation from the retention balloon and a smaller mass; 
         FIG. 12  is a rear elevational view of the catheter end as seen in  FIG. 11 ; 
         FIG. 13  is a front elevational view of the catheter end as seen in  FIG. 11 ; 
         FIG. 14  is a top plan view of the catheter as seen in  FIG. 11 ; 
         FIG. 15  is a side elevational view of the distal catheter ends as shown in  FIG. 11  showing the relative masses; 
         FIG. 16  is a rear elevational view of the distal catheter ends as shown in  FIGS. 2 and 12  showing the widths of the bullet tips; 
         FIG. 17  is a top plan view of the catheter as seen in  FIGS. 4 and 14  showing in outline the shapes of the stylet sockets for the first version shown in  FIG. 1 , and the second version shown in version two in  FIG. 11 ; 
         FIG. 18  is a front elevational view of a retention balloon as seen in PEG tubes without a tip bolus showing gastric mucosa occluding the port; 
         FIG. 19  is a side elevational view of the catheter, similar to  FIG. 11 , showing the gastric mucosa being held away from the port opening; 
         FIG. 20  is a rear elevational view of the catheter end as shown in  FIG. 12  showing the gastric mucosa being held away from the port; 
         FIG. 21  is a side elevational view of catheter as shown in  FIG. 11 , but completed with the addition of the external proximal bolster; 
         FIG. 22  is a partial sectional view of the catheter as seen in  FIG. 21  taken along lines  22 - 22  of  FIG. 21  and a partial side elevational view of  FIG. 21  showing the bolus tip  116  and internal bolster  120  being stretched for insertion and air being expelled out of the catheter internal retention bolus  120 ; 
         FIG. 23  is a top plan view of the catheter as shown in  FIG. 21  showing the valved port for the administration set; 
         FIG. 24  is a partial sectional view of the catheter as seen in  FIG. 21  taken along lines  22 - 22  of  FIG. 21  and a partial side elevational view of  FIG. 21  showing the bolus tip in its final stretched position for insertion; 
         FIG. 25  is a partial sectional view of the catheter as seen in  FIG. 21  taken along lines of  22 - 22  of  FIG. 21  and a partial side elevational view of  FIG. 21  shown with the stylet removed and the bolus in its final relaxed position showing air re-entering the catheter; 
         FIG. 26  is a sectional view of the catheter seen in  FIG. 21 , taken along the line  22 - 22 ; showing the blunt needle removed trapping the air in the inflated catheter of  FIG. 21 , and showing the blunt needle being removed; and 
         FIG. 27  is a side elevational view of the catheter  21 , in-situ. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings and particularly to  FIGS. 1-6  the distal end of a catheter embodying features of the invention is seen generally at  10 . The catheter illustrated includes a 20 French (20 Fr) catheter tube  12  molded of a soft, resilient plastic such as silicone. Secured to the corresponding end of the tube  12  is a retention balloon bolster  14  and a bolus tip  16 , molded unitarily from the same plastic. 
     Referring specially to  FIGS. 5 and 6 , the tube  12  comprises a silicone body  22  containing a stainless steel wire coil spring  24 . The coil spring  24  extends from a suitable set connector on the proximal end of the tube  12  (not shown) to a location  26  immediately adjacent the retention balloon bolster  14 . Accordingly, the balloon bolster  14  surrounds the tube portion  28  which is not supported by the spring  24 . The tube body  22  is formed with the spring  24  in it in the manner described in Quinn U.S. Pat. No. 6,077,243. A lumen  29  extends through the length of the tube body  22 . 
     The retention bolster  14  comprises a tire-shaped balloon  20 . The tire-shaped balloon  20  is preformed in that shape from silicone rubber and includes parallel sidewalls  36  and  37 . The sidewall  37  is the rear sidewall while the sidewall  36  is the front sidewall. Connecting the sidewalls  36  and  37  (in the language of tire construction) is the treadwall  39 . The treadwall  39  is semi-circular in cross-section. 
     The annular inner peripheries of the sidewalls  36  and  37  are defined by beads  42  and  43 , respectively. Each of the beads  42  and  43  comprises a cylindrical sleeve. The sleeve  43  extends forwardly of the rear sidewall  37 . Thus, it is inside the balloon  20 . The sleeve  42  extends forwardly of the front sidewall  36 . Thus, it is outside the balloon  20 . The cylindrical inner surfaces of the sleeves  42  and  43  are glued to the outer surface of the tube body  22  wall with a silicone adhesive. 
     Air is trapped in the space  44  within the preformed balloon  20  when the bead sleeves  42  and  43  are glued to the body  22  to assemble the tube  12  and balloon  20 . The front and rear sidewalls  36  and  37  extend parallel to each other from their corresponding bead sleeves  42  and  43  to their juncture with the semi-circular treadwall  39 . A flat front surface  56  is, accordingly, defined on the outside of the front wall  36  while a flat rear surface  57  is defined on the outside of the rear wall  37 . 
     According to the invention, the flat front surface  56  forms the balloon  20  retention surface for the catheter  10 . The flat rear surface  57  is flush with the tube  12  at its port  61 . Thus, the tube  12  does not protrude forwardly beyond the balloon  20 . 
     The body  22  of the tube contains a deflation lumen  65  which extends the length of the tube segment between the coil spring  24  and the outer surface  47  of the tube body. The deflation lumen  65  communicates with the inside of the balloon  20  through a radial aperture  66  in the tube segment body  41 . The lumen  65  is plugged at  67  under the balloon bead  63 . It is also plugged adjacent its opposite end, i.e., normally at the aforementioned set connector (not shown). 
     As has been pointed out, the bolus tip  16  is molded unitarily with the retention balloon bolster  14 . The tip  16  comprises a cylindrical base  72  defining a port  74 , the port being co-axial with, and having the same ID (inside diameter) as that of the tube lumen  29 . 
     Cantilevered to one side of the cylindrical base  72  is the bolus tip nose section  77 . The nose section  77  includes a bullet nose  79  having a semi-spherical outer surface  81  and an internal socket  83 . 
     Bracketing the socket  83 , and extending radially inwardly toward the axis of the cylindrical base  72 , are opposed side walls  85  and  86 . The side walls  85  and  86  have corresponding upper edges  88  and  89  which slope gradually toward the cylindrical base  72  and join it on opposite sides of the lumen port  61 . 
     To place the catheter  10  in a patient&#39;s bladder through the urethra or into the stomach through a stoma, the nose section  77  of the bolus tip  16  is manually moved to the position shown in  FIG. 8 , i.e., into its extended position. A stylet  90 , such as seen in  FIG. 7 , is then inserted through the tube  12  from its proximal end (not shown) until the end  91  of the stylet is seated in the socket  83  of the bolus tip nose section  77 . 
     A plug (not shown) in the air passage  65  near the proximal end of the tube  12  is removed so that air can escape from the balloon  20 . Accordingly, when the stylet  90  is employed to insert and push the catheter through a stoma, for example, the tube portion  28  stretches, the balloon  20  elongates axially and shrinks radially to where the bolster  14  and bolus tip pass through the stoma. 
     With the catheter  10  in place, the stylet  90  is pulled out. The balloon  20  resumes its normal shape. The tip  16  retracts to the position shown in  FIGS. 1-5 . A plug is reinserted in the lumen  65  near the set connector. The catheter  10  is operational. 
     Referring now to  FIGS. 11-14 , another embodiment of the catheter end shown in  FIG. 1  is shown at  110 . The function and operation of the two versions  110  and  10  are identical.  FIG. 13  shows the socket  183  that has an oblong shape rather than the round shape of socket  83 . In the case of socket  83  the stylet  90  is the approximately the same size and shape as the socket  83 . The socket  183  has an oblong shape that has the same internal cross sectional area as socket  83 . When stylet  90  is inserted into socket  183  the bullet bolus tip  116  expands to accept the stylet  90 . Socket  83  is a circle with an outside diameter of 0.066.″ Socket  183  has a height of 0.030″ and a width of 0.093. 
     The catheter end  110  provides a lower profile when in place in the body cavity.  FIG. 15  shows the lower comparable height of bullet tip bolus  16  in place.  FIG. 16  shows that the width of bullet tip boluses  16  and  116  are the same width. 
       FIG. 17  shows a dotted line top plan view of the internal shape of sockets  83  and  183 . 
       FIG. 18  shows mucosa  94  occluding a standard PEG type port.  FIGS. 19-20  shows the open spaces  95  created by the tip  116  of assembly  110 . 
       FIGS. 21 ,  22  and  23  show the external bolster  118 . The external bolster has the same basic construction as the internal bolster  116 . It attaches to tube  12  at section  119  which has no spring reinforcement. The deflation lumen  65  communicates with the inside of bolster  118  through radial aperture  122  in the tube segment body  41 . A plug  123  is placed in the proximal end of the deflation lumen  65  to prevent the escape of air. The external bolster  118  contains silicone slit valve  124  that accepts a blunt tip needle  126  to allow air to enter the system connecting the proximal external bolster  118  with the distal internal bolster  116 . Bolster  118  also contains, at the axial midpoint, another silicone slit valve  128  that accepts an access enteral feeding set (not shown) or a urologic drainage set. 
     Now referring to  FIGS. 21 ,  22  and  23  the external proximal bolster  118  contains a tire shaped balloon  130 . As is the internal bolster balloon  120 , the balloon  130  is preformed in that shape from silicone rubber and includes parallel walls  132  and  134 . The side wall  132  is the top most proximal wall and the side wall  134  is the bottom wall. Connecting the side walls  132  and  134  (in the language of tire construction) is the treadwall  136 . The treadwall  136  is semi-circular in construction. 
     The annular inner peripheries of the side walls  132  and  134  are defined by beads  138  and  140 , respectively. Each of the beads  138  and  140  comprises a cylindrical sleeve. The sleeve  138  extends below the top side wall  132 . Thus it is inside the balloon  130 . The sleeve  140  extends above the bottom wall  134 . Thus it is also inside the balloon. The cylindrical inner surfaces of the sleeves  138  and  140  are glued to the outer surface of the tube body  22  wall with a silicone adhesive. 
     Air is trapped in the space  142  within the preformed balloon  130  when the bead sleeves  138  and  140  are glued to the body  22  to assemble the tube  12  and balloon  130 . The top and bottom walls  132  and  134  extend parallel to each other from their corresponding bead sleeves  138  and  140  to their juncture with the semi circular treadwall  138 . A top flat surface is  144  is, accordingly, defined on the top outer wall  132  while a flat surface  146  is defined on the bottom wall  134  which is in contact with the patient&#39;s skin. 
     According to the invention, the flat bottom surface  146  forms the external retention surface for catheter  110  and is contact with the patient&#39;s skin. The flat top surface  140  is flush with the top of tube  12  at the point that it contains slit valve  128 . Thus, the tube  12  does not protrude above the surface of balloon  130 . 
     Now also referring to drawings  21 ,  22  and  23 , a blunt needle  126  is inserted into external balloon  130  through slit valve  124  to allow the escape of air from the internal bolus balloon  120  as the balloon is gradually deformed by the stylet.  FIG. 24  shows the balloon  120  fully deflated and deformed and ready for insertion.  FIG. 25  shows the balloon in its final in-situ shape after placement and the re-entry of air as the balloon  120  returns to its preformed shape when the stylet is removed after placement.  FIG. 26  shows the device  110  in place and the blunt needle  124  removed thereby trapping air in the balloon  120  and  118 .  FIG. 27  shows the device  110  in place in the patient&#39;s body  92  with the external balloon  118  against the patient&#39;s skin and the internal retention balloon  2120  against the stomach mucosa. 
     With the invention placed in-situ feeding or drainage can be started by placing an appropriate feeding set into the slit valve  128  that is glued into top balloon bolster  118 . 
     To remove the catheter after it is no longer required, simply place a small cut in the external balloon  118 , thereby allowing the air in the internal balloon bolus  116  to escape and thereby deform the balloon as the catheter is gently pulled out.