Abstract:
This document provides catheters (e.g., urinary catheters) having safety mechanisms that indicate when a distal end of the device enters an intended cavity (e.g., a human&#39;s bladder) and is properly positioned, thereby preventing inflation of a retention balloon in an unintended location (e.g., the urinary canal). For example, safety urinary catheters and methods for using and inserting such safety urinary catheters are provided.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/376,094, filed Aug. 23, 2010. The contents of the foregoing application is hereby incorporated by reference in their entireties. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    This document relates to urinary catheters with a safety mechanism that indicates when the distal end of the device entered a human&#39;s bladder and is properly positioned, thereby preventing inflation of the retention balloon in the urinary canal. For example, this document provides urinary catheters that can include a body having a proximal portion and a distal portion with the body having a safety mechanism to indicate when the distal portion of the catheter body has entered the urinary bladder. 
         [0004]    2. Background Information 
         [0005]    Catheters are medical devices that can be used to facilitate various medical procedures. A catheter can be inserted into the body of a patient and thereby allow drainage or removal of fluids or other material. For instance, a typical internal urinary catheter is known as a Foley catheter. A Foley catheter can include a hollow tube having a tip at one end which is inserted into the body. The tip can have one or more openings that communicate with the interior of the hollow tube. The other end of the tube can be disposed externally of the body and can be connected to a waste receptacle by way of a flexible discharge conduit. An annular inflatable portion, or retention balloon, can be spaced inwardly from the tip. Such a balloon can be deflated during placement of the catheter into the body and thereafter inflated after the tip is properly positioned within the body in the urinary bladder of the patient. 
       SUMMARY 
       [0006]    This document provides catheters having a safety mechanism that is capable of indicating when the distal end of the device entered a bladder (e.g., a human&#39;s bladder) and is properly positioned, thereby preventing inflation of a retention balloon in the urinary canal. In some cases, a urinary catheter can be improperly inserted so that inflation of the retention balloon is initiated while it is still within the urethra (urinary canal). The force exerted by the retention balloon on the walls of a restricted body channel may cause disastrous complications such as ruptured channel walls in addition to considerable patient discomfort. A urinary catheter provided herein can be used to avoid such improper insertions and such complications. 
         [0007]    As described herein, a catheter can be designed to have a body having a proximal portion and a distal portion, a retention balloon near the end of the distal portion, and a safety element on the catheter body located proximal to the retention balloon. The catheter can be configured such that the safety element changes position when the retention balloon is inside a body cavity. The catheter can be a urinary catheter. The catheter can be a Foley catheter. 
         [0008]    In some cases, the safety element can be a flexible flap. The safety element can be attached to the catheter body immediately proximal to the retention balloon. The safety element can be made out of the same material as the catheter body or a different material. The safety element can be folded against the catheter body while the catheter is within a body passage, urinary canal, or urethra. The safety element can become extended when it is inside a body cavity such as the urinary bladder. The safety element can be perpendicular to the longitudinal axis of the catheter body. The safety element can be connected to a communication structure near the distal tip of the safety element. 
         [0009]    A communication structure can be connected to the distal tip of the safety element by being securely tied to the distal tip or by being molded into the safety element. The communication structure can enter the catheter body through an opening that is proximal to the connection point of the safety element. The opening can connect to the drainage lumen. The opening can connect to a communication structure lumen that is specific for the communication structure. In some cases, the communication structure can be located outside the catheter body. The communication structure can be a long piece of suture that extends the length of the catheter. In some cases, a communication structure can be a latex band. 
         [0010]    A communication structure can be designed to have an indicator near the proximal end. Such an indicator can be a specific length of the communication structure that is a color or pattern that contrasts the other portions of the communication structure. In some cases, the indicator can be a knot or a bead. The indicator can change position along the longitudinal axis depending upon the configuration of the safety element. When the safety element is in a folded configuration, the indicator can be in a more proximal position. In the more proximal position, the indicator can be located distal to the funnel. When the safety element is in an extended configuration and perpendicular or nearly perpendicular to the longitudinal axis, the indicator can be in a more distal position. In the more distal position, the indicator can be located inside the funnel. In the more distal position, the indicator can be flush with the proximal end of the funnel. In the more distal position, the indicator can be distal to the funnel. The position of the indicator can indicate whether or not the retention balloon can be inflated. If the indicator is in the more proximal position, the retention balloon should not be inflated. If the indicator is in the more distal position, the retention balloon can be inflated. 
         [0011]    This document also provides methods for using a catheter with a safety mechanism to know when the distal end of the catheter has entered a human&#39;s body cavity. In some cases, a method provided herein can include applying lubrication to at least a portion of the catheter. The lubricant can include a water-based lubricant. The catheter can be a Foley catheter, and the body cavity can be the urinary bladder. The method can include attaching a pump to the inflation lumen of the catheter and a tube that connects to a urine storage bag to the drainage lumen of the catheter. This step may optionally be performed later in the method. The method can include using an introducer tip that defines an insertion opening. The introducer tip can be used to insert the distal end of the catheter body in a bodily opening and into a human&#39;s bodily passage. The bodily opening can be the meatus, and the bodily passage can be the urinary canal or the urethra. The method can include advancing the catheter into the bodily passage while monitoring the distal portion of the safety mechanism that has a visible indicator that is distal to the funnel. The method can include stopping the advancement of the catheter when the position of the indicator changes in relationship to the funnel along the longitudinal axis of the catheter body. The indicator may no longer be visible once the displacement in the longitudinal direction has occurred. The change in location of the indicator along the longitudinal axis from a more proximal position to a more distal position can indicate that the retention balloon has entered a body cavity. The body cavity can be a urinary bladder. The method can include inflating the retention balloon after the change in the position of the indicator has been observed. The method can include using the catheter with a safety mechanism to enable a human to void his or her bladder. 
         [0012]    In general, one aspect of this document features a catheter comprising, or consisting essentially of, (a) a body having a proximal portion and a distal portion, (b) a retention balloon near the end of the distal portion, and (c) a safety element on the body located proximal to the retention balloon, wherein the catheter is configured such that the safety element changes position when the retention balloon is inside a body cavity. The safety element can comprise a flap located proximal to the retention balloon and can be connected to a communication structure. The flap can be folded against the catheter while the catheter is inserted, and the flap can be extended only when the retention balloon is inside the body cavity. The communication structure can be a suture that extends from the tip of the safety element to the proximal end of the catheter. The communication structure can comprise an indicator that signals when the safety element is extended or non-extended. The flap can be latex. The catheter can be a urinary catheter. The catheter can be a Foley catheter. The body cavity can be a urinary bladder. 
         [0013]    In another aspect, this document features a method for using a catheter comprising, or consisting essentially of, (a) inserting a catheter into a patient, the catheter comprising, or consisting essentially of, a body having a proximal portion and a distal portion, a retention balloon near the end of the distal portion, a safety mechanism on the body located proximal to the retention balloon, and (b) inflating the retention balloon after the safety mechanism signals when the retention balloon is inside a body cavity. 
         [0014]    Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting. 
         [0015]    Other features and advantages of the invention will be apparent from the following detailed description, and from the claims. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0016]      FIG. 1  is a perspective view of a catheter in accordance with one embodiment. 
           [0017]      FIG. 2A  is a close up view of proximal and distal ends of a catheter when a safety element is in an extended configuration in accordance with one embodiment. 
           [0018]      FIG. 2B  is a close up view of proximal and distal ends of a catheter when a safety element is in a folded configuration in accordance with one embodiment. 
           [0019]      FIGS. 3A and 3B  are cross sectional views taken along line  3 - 3  of  FIGS. 2A and 2B , in accordance with some embodiments. 
           [0020]      FIG. 4A  is a close up view of proximal and distal ends of a catheter when a safety element is in a folded configuration in accordance with one embodiment. 
           [0021]      FIG. 4B  is a close up view of proximal and distal ends of the catheter of  FIG. 4A  when the safety element is in an extended configuration in accordance with one embodiment. 
           [0022]      FIG. 5A  is a side view of the urinary catheter during insertion into a urinary canal in accordance with one embodiment. 
           [0023]      FIG. 5B  is a side view of the urinary catheter of  FIG. 5A  after it has been inserted into the urinary bladder in accordance with one embodiment. 
           [0024]      FIG. 6  is a process of using a catheter with a safety mechanism to prevent premature inflation of the retention balloon in accordance with one embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]      FIG. 1  is a perspective view of a Foley-type catheter generally designated with reference number  20 . Catheter  20  can be made of polyvinyl chloride (PVC), polyurethane, silicone rubber, nitrile rubber, or other appropriate material that is biocompatible, hydrophobic, and generally inert with respect to physiological fluids it contacts. Catheter  20  can have a polished surface. Catheter  20  (e.g., urinary catheter) can be between fifteen and fifty-five centimeters in length and between fifteen and seventy millimeters in diameter. 
         [0026]    To assist in the description of the components of catheter  20 , the following coordinate terms are used. A “longitudinal axis” is generally parallel to a section of the catheter. In  FIG. 1 , the longitudinal axis is generally parallel to an elongated flexible body portion  22 . As used herein, “the longitudinal direction” refers to a direction substantially parallel to the longitudinal axis. The term “distal” is used in reference to an end of catheter  20  near the patient&#39;s body. The term “proximal” is used in reference to an end of catheter  20  near a funnel  60 . 
         [0027]    Catheter  20  can include a catheter body  22  with a proximal end  24  and a distal end  26 . Catheter  20  can include a funnel  60  at or near proximal end  24 . Funnel  60  can define one or more lumens. For example, funnel  60  can be split to define an inflation lumen  34  and a drainage lumen  36 . Inflation lumen  34  can extend to a water/air pump  62  through a tube  64 . Water/air pump  62  can be employed to flow water or air into inflation lumen  34 . Drainage lumen  36  can extend to a urine storage bag  68  through a tube  66 . Urine storage bag  68  can be employed to collect discharged urine from a patient. 
         [0028]    Catheter  20  can include a retention balloon  28 . With reference to  FIGS. 2A and 2B , catheter  20  can include fluid tight seals  30  and  32 . Retention balloon  28  can be deflated for insertion into a patient. Pump  62  can pump water through inflation lumen  34  and ultimately into retention balloon  28  located in the patient&#39;s bladder. Retention balloon  28  can retain distal end  26  of catheter  20  in the bladder, and maintain a drainage port  38  in the proper position to allow urine to pass through. 
         [0029]    Drainage lumen  36  can extend from distal end  26  to proximal end  24 . At proximal end  24 , fluid (e.g., urine) passing through drainage lumen  36  can enter funnel  60  and continue to pass through tube  66  to urine storage bag  68 . While funnel  60  may be connected to urine storage bag  68  for an extended period of time, it may only need to be connected to water/air pump  62  for a long enough period of time to inflate retention balloon  28  of catheter  20 . 
         [0030]    Distal end  26  can include one or more openings  38  in fluid communication with drainage lumen  36  to facilitate drainage of urine from a bladder of a patient. In one embodiment, catheter  20  can have one opening  38  at distal end  26 . Any number of openings can be used. For example, distal end  26  can have one, two, three, four, five, or more openings. The opening  38  shown is oval shaped. Opening  38  can be any appropriate shape, such as circular or rectangular. If multiple openings are present, each opening can be configured to have the same shape or a different shape. In some cases, if multiple openings are present, the multiple openings can be positioned in a variety of ways. For example, the openings can be positioned along the same longitudinal line. In some cases, the openings can be positioned equidistant from distal end  26  of catheter  20 . The openings can be positioned according to any combination of spacing about the outer surface of catheter  20  at distance from the tip of catheter  20 . 
         [0031]      FIGS. 2A and 2B  are close-up views of distal end  26  and proximal end  24  of catheter  20 . A catheter provided herein can include a safety mechanism. A safety mechanism can include a safety element  40  connected to a communication structure  42 . Safety element  40  can be connected to catheter body  22  proximal to retention balloon  28 . In one embodiment, safety element  40  can be a flexible flap that is connected to catheter body  22  proximal to retention balloon  28 . 
         [0032]    Safety element  40  can be made out of polyvinyl chloride (PVC), silicone rubber, nitrile rubber, latex, or other appropriate material. For example, safety element  40  can be a flap made out of the same material as catheter  20  or a different material. Safety element  40  can be permanently affixed to catheter body  22  or detachable. If safety element  40  is detachable, it can be removed from catheter  20  by pulling firmly on communication structure  42  at proximal end  24  of catheter  20 . In some case, a catheter provided herein can be designed to have a safety element  40  that is not a balloon and is not inflatable. In some cases, a catheter provided herein can be designed to have a safety element  40  that is non-inflatable. 
         [0033]    Safety element  40  can be connected to catheter body  22  in such a way that when safety element  40  is in an extended configuration, it is about perpendicular to the longitudinal axis, as shown in  FIG. 2A .  FIG. 2B  shows a folded or bent position of safety element  40 . This folded or bent position can be used when catheter  20  has not yet reached the bladder. When catheter  20  is inserted and advanced into the urinary canal, safety element  40  is flexible enough so it folds against catheter body  22  such that safety element  40  is parallel or almost parallel with the longitudinal axis. Safety element  40  can have enough flexibility so that it can extend away from catheter body  22  when not restrained or restricted by, for example, a urinary canal. Safety element  40  can be between 5 mm and 30 mm in length. 
         [0034]    Communication structure  42  can be attached to a distal tip  44  of safety element  40 . In some cases, communication structure  42  can extend in the longitudinal direction and can be visible at a proximal end  24  of catheter  20 . In some cases, communication structure  42  can be securely tied to distal tip  44  of safety element  40  or molded into safety element  40 . With further reference to  FIGS. 2A and 2B , communication structure  42  can enter catheter body  22  at an opening  46  that can be proximal to a point where safety element  40  is connected to catheter body  22 .  FIG. 2A  shows safety element  40  in an extended configuration, with communication structure  42  connected to distal tip  44  of safety element  40  such that length l of communication structure  42  is pulled outside catheter body  22 . The proximal end of communication structure  42  can be placed into urine storage bag  68  or it can be excluded from urine storage bag  68  when urine storage bag  68  is attached to tube  66  by compressing communication structure  42  in a seal. In some cases, there can be a small hole in the proximal end of catheter body  22  for communication structure  42  to exit an internal portion of catheter  20  such that communication structure  42  does not come into contact with drainage lumen  36 , tube  66 , or urine storage bag  68 . 
         [0035]    In one embodiment, communication structure  42  can be a suture. In some cases, communication structure  42  can be a string, ribbon, or latex band. 
         [0036]    When safety element  40  is folded against catheter body  22 , an indicator  48  on communication structure  42  can be seen at proximal end  24  near a base of funnel  60 .  FIG. 2B  shows an indicator  48  that is visible at proximal end  24  near the base of funnel  60 . When indicator  48  on communication structure  42  is visible, it signals that safety element  40  is in the folded configuration and retention balloon  28  should not be inflated. 
         [0037]      FIG. 2A  shows safety element  40  in an extended configuration, and indicator  28  is no longer visible outside funnel  60 . When safety element  40  has been advanced completely into the urinary bladder, safety element  40  can become perpendicular to the longitudinal axis, causing communication structure  42  to be pulled towards distal end  26  and indicator  48  to no longer be visible at proximal end  24  of catheter  20 . 
         [0038]    Indicator  48  of communication structure  42  can be a different color or pattern than the rest of communication structure  42 . For example, indicator  48  can be red. Indicator  48  can be a segment on communication structure  42  that is the same length as l ( FIG. 2A ) that is displaced when safety element  40  moves from a folded configuration to an extended configuration. In some cases, indicator  48  can be a knot or a bead. Indicator  48  can be a different type of material than the other portions of communication structure  42 . For example, indicator  48  can be a suture, and communication structure  42  can be latex or vice-versa. Indicator  48  can be located at a position on communication structure  42  such that indicator  48  is visible when safety element  40  is in a folded configuration and not visible when safety element  40  is in an extended configuration. 
         [0039]      FIGS. 3A and 3B  are cross sectional views taken along line  3 - 3  in FIGS.  2 A and  2 B. With reference to  FIG. 3A , openings  38  and  46  shown in  FIGS. 2A and 2B  can be connected to drainage lumen  36 , and communication structure  42  can be configured to extend within drainage lumen  36 . In some alternative embodiments, with reference to  FIG. 3B , opening  46  shown in  FIGS. 2A and 2B  can be connected to a communication structure lumen  48 , which is a separate lumen specifically for communication structure  42  to pass through to proximal end  24  of catheter  20 . In either drainage lumen  36  or communication structure lumen  48 , there may be a hook or loop (not shown) at proximal end  24  to hold communication structure  42  to one side of funnel  60 . 
         [0040]      FIGS. 4A and 4B  are close-up views of distal end  26  and proximal end  24  of catheter  20  with an alternative embodiment of a safety mechanism. In such cases, a safety mechanism can included a safety element  40  that is proximal to a retention balloon  28 . Communication structure  42  can be connected to a distal tip  44  of safety element  40  but does not enter catheter  20  through an opening. Communication structure  42  can run parallel to catheter body  22  along the longitudinal axis to proximal end  24  of catheter  20 . There can optionally be a hook or a loop  50  on or near funnel  60  to hold communication structure  42  in close proximity to proximal end  24  of catheter  20 . Communication structure  42  can optionally be enclosed within a lumen that is connected to but is external to catheter body  22  as opposed to internal (lumen not shown). In  FIG. 4A , safety element  40  is folded against catheter body  22 , and an indicator  48  on communication structure  42  is visible past funnel  60  at proximal end  24  of catheter  20 . When indicator  48  on communication structure  42  is located proximally to funnel  60 , it signals that safety element  40  is still within the urinary canal and that retention balloon  28  should not be inflated. When safety element  40  has been advanced completely into the urinary bladder, safety element  40  becomes perpendicular to the longitudinal axis, causing communication structure  42  to be pulled towards distal end  26  and indicator  48  to be displaced along the longitudinal axis of catheter body  22 . In this embodiment, indicator  48  can always be visible and the position of indicator  48  can signal the configuration of safety element  40 .  FIG. 4B  shows safety element  40  in an extended configuration that would occur when it is inside the bladder. Indicator  48  is now located just above the proximal end of funnel  60 . When indicator  48  has shifted distally from its original position, this signals that retention balloon  28  can be inflated. Safety element  40  can optionally be detachable from catheter body  22 . Safety element  40  can be removed from catheter  20  by pulling firmly on communication structure  42  at proximal end  24  of catheter  20 . 
         [0041]    The embodiments shown in  FIGS. 4A-4B  where communication structure  42  is not housed within drainage lumen  36  may help to reduce the risk of an infection. Additionally, catheter  20  can be configured so communication structure  42  never comes into contact with drainage lumen  36 , tube  66 , or urine storage bag  68  which may also reduce infection risk. 
         [0042]      FIGS. 5A and 5B  are side views showing placement of a catheter provided herein (e.g., catheter  20 ) relative to the urinary tract of a male patient. Catheter  20  can also be used for a female patient. As shown in  FIG. 5A , an introducer  52  can be used to insert distal end  26  of catheter  20  into the meatus opening in the patient into the urinary canal  74  towards bladder  70 . As shown, distal end  26  is within the urinary canal  74 . The wall of the urinary canal presses against flexible safety element  40  thereby causing safety element  40  to fold against the longitudinal axis of catheter body  22 . Indicator  48  on communication structure  42  is visible outside the body near proximal end  24  of catheter  20 , indicating that retention balloon  28  should not be inflated. If catheter  20  is pushed into a false lumen  74  instead of bladder  70 , indicator  48  will still be visible since the force of the lumen wall will keep safety element  40  in the folded configuration. False lumen  74  may be shorter and/or wider than the one depicted in  FIGS. 5A and 5B . In some cases, false lumen  74  is nearly the exact dimensions of catheter  20  since it is created when catheter  20  is being advanced towards the bladder. 
         [0043]      FIG. 5B  shows distal end  26  of catheter  20  inside bladder  70 . Flexible catheter body  22  extends from bladder  70  through the meatus opening in the patient. Openings  38  on distal end  26  of catheter  20  transfer urine from the patient&#39;s bladder  70  to the urine storage bag  68  (not shown). Safety element  40  can be in an extended position, perpendicular to the longitudinal axis of catheter body  22 . In the extended position, safety element can pull communication structure  42  distally, causing indicator  48  to no longer be visible at proximal end  26 . When indicator  48  on communication structure  42  is no longer visible at proximal end  26 , this signals that retention balloon  28  is fully inside bladder  70  and pump  62  (not shown) can be used to inflate retention balloon  28 . 
         [0044]      FIG. 6  is a process of using a catheter provided herein (e.g., catheter  20 ). It will be appreciated by the skilled practitioner that the illustrated process can be modified in a variety of ways. For example, appropriate sterilization techniques and application of lubrications can be performed. 
         [0045]    As shown in  FIG. 6 , a process can start at step  600 . At step  610 , a catheter is provided comprising an introducing member, elongated flexible body portion, and a safety mechanism. A urine storage bag and pump may be connected to a catheter funnel at this time if the communication structure of a safety mechanism does not pass through the inflation lumen or the drainage lumen. At step  620 , the catheter can be inserted into the patient and advanced along the urinary canal. While the catheter is being advanced, the indicator at the distal end of the catheter is visually monitored. At step  630 , advancing the catheter is stopped when the indicator is no longer visible or it has shifted distally from an originally position. At this point, the presence of the distal end of the catheter within the bladder can be confirmed by gently pulling on the communication structure and watching the indicator appear and disappear. If the safety mechanism is removable, the communication structure can be pulled until the safety element breaks free from the catheter body. Subsequently, at step  640 , the retention balloon can be inflated, and the patient&#39;s urine is funneled through the catheter and into a urine storage bag at step  650 . The process can end at step  660 . 
       Other Embodiments 
       [0046]    It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.