Patent Publication Number: US-2013245496-A1

Title: Urinary catheter anti-reflux and pathogen block device

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Patent Application No. 61/631,644, entitled “Urinary Catheter Anti-Reflux and Pathogen Block Device,” and filed on Jan. 9, 2012, which is incorporated herein by reference. 
    
    
     RELATED ART 
     Urinary tract infections (“UTIs”) are the most common type of healthcare-associated infection, accounting for more than 30% of infections reported by acute-care hospitals. Virtually all healthcare-associated UTIs are caused by use of instrumentation in the urinary tract. Catheter-associated urinary tract infections (CAUTIs) are associated with increased morbidity, hospital costs, and length of stay. In addition, bacteriuria, the presence of bacteria in urine not due to contamination from urine sample collection, commonly leads to unnecessary antimicrobial treatments as urinary drainage systems are often reservoirs for multi-drug resistant bacteria. An estimated 17% to 69% of CAUTIs may be preventable with recommended infection control measures, leading to the prevention of 380,000 infections and 9000 deaths related to CAUTI per year. 
     The most common cause of UTIs is the backflow of urine into the urinary tract when the catheter collection container is raised above the bladder level. Microbial pathogens can enter the urinary tract by migration along the outside of the catheter in the periurethral mucous sheath or by movement along the internal lumen of the catheter from a contaminated collection container or the catheter-drainage tube junction. Reductions in the numbers of such CAUTIs will have a positive effect on patient health and will decrease the overall cost of treating patients utilizing urinary catheters. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure can be better understood with reference to the following drawings. The elements of the drawings are not necessarily to scale relative to each other, emphasis instead being placed upon clearly illustrating the principles of the disclosure. Furthermore, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1A  is a diagram illustrating an exemplary embodiment of an anti-reflux device. 
         FIG. 1B  is a side view illustrating an exemplary embodiment of an anti-reflux device. 
         FIG. 2  is a diagram illustrating an exemplary embodiment of a hose barb connection, such as depicted by  FIG. 1 . 
         FIG. 3  is a diagram illustrating an exemplary embodiment of a duckbill backflow prevention valve. 
         FIG. 4  is a diagram illustrating an exemplary embodiment of a cruciform backflow prevention valve. 
         FIG. 5  is a diagram illustrating an exemplary embodiment of an exit device, such as depicted by  FIG. 1 . 
         FIG. 6  is a cross sectional view of an exemplary embodiment of an exit device, as depicted in  FIG. 5  taken at section line  6 - 6 . 
         FIG. 7  is a diagram illustrating an exemplary embodiment of a catheter anti-reflux system. 
     
    
    
     DETAILED DESCRIPTION 
     This presently disclosed devices and systems prevent the backflow of urine into a catheter from both the catheter interconnection tube and the urine collection container through the use of a one-way or check valve. In certain embodiments, the device contains an anti-microbial agent that is compatible with the human body. The device provides a valve with a low cracking pressure, or pressure required to open the valve, to allow passage of urine. The device also prevents blockage of the valve caused by the presence of solids in the urine stream. Very low opening pressure is required to prevent migration of urine back into the urinary tract. The valve and other device components do not act as a bacteria source and may be sanitized using methods known in the art, for instance by autoclave, gas sterilization or irradiation methods. 
       FIG. 1A  is a diagram illustrating an embodiment of an anti-backflow catheter device  20 . The device  20  comprises an elongated hollow tubular member  30  having an inlet chamber  32  and an outlet chamber  34 . Inlet chamber  32  further comprises a tapered end portion  36  which functions as a catheter connection. Urine enters the device  20  through the tapered end portion  36 , enters inlet chamber  32  and flows towards a medial portion  33  of the tubular member  30 . Tubular member  30  incorporates standard hose barb connections  38  and  39  placed at the outside ends of the inlet chamber  32  and outlet chamber  34 , respectively. The connections  38  and  39  serve as attachment points for the catheter end ( 38 ) and urine collection end ( 39 ) tubing. A hose barb connection is generally a tapered device with one or more continuous ridges or bumps on a fitting that are used to grip the inside diameter of a tube and seal the connection. An exemplary hose barb connection is illustrated in  FIG. 2 . Connections  38  and  39  are tapered cylindrical pieces or parts located at the at the outside ends of the inlet chamber  32  and outlet chamber  34  for attaching and securing tubing leading to the catheter or urine collection container (not shown). Each barb  38  and  39  comprises one or more of evenly spaced rings  43  with increasingly large diameters. The widest portion of each ring is formed with an angular barb-like protrusion  42 . The tubing leading to the catheter and urine collection container (not shown) is easily installed on connections  38  and  39  because there is little resistance when fitting the tubing over the rings  43  in the direction towards a medial portion  33  of tubular member  30 . The tubing is flexible and expands over the barbs  42  after placement over the connections  38  and  39 . Grip and seal occur as the tube begins to relax to its original inside diameter behind the barbs  42  and thus resists any force applied to remove the tubing. Barb-like protrusions grip the inside surfaces of the tubing and resist forces in the direction away from a medial portion  33  of tubular member  30 . The hoses therefore snugly fit over connections  38  and  39  and prevent slipping or leaking of fluids. Connections  38  and  39  help to prevent twisting or kinking of the catheter and urine collection container tubing (not shown). In one embodiment, inlet hose barb connection  38  may be coated on its exterior with at least one layer of an antimicrobial material to prevent microbial growth at the catheter connection. 
     Referring again to  FIG. 1A , the tubular member  30  is attached directly to the catheter (not shown) via hose barb connection  38  to minimize the volume of urine which may backflow into the bladder. The tubular member  30  is constructed of a rigid, high-strength and transparent material which retains its form over a wide range of temperatures. One example of such a material is polysulfone, which belongs to a family of thermoplastic polymers. These polymers are known for their toughness and stability at high temperatures and will not promote microbial growth. This material may be sanitized using methods known in the art, for instance by autoclave, gas sterilization or irradiation methods. 
     Turning now to  FIG. 1B , a needleless sample valve  50  is placed at the medial portion  33  of tubular member  30 . In one embodiment, the sample valve  50  is constructed from molded polycarbonate materials and permanently attached to the tubular member  30 . Sample valve  50  allows access to a sample volume  52  of urine collected directly from the catheter (not shown). This allows for aspiration of a small amount of urine, for example 10 cc, for further examination (i.e., urinalysis or culture). Access to the sample volume  52  is possible without the use of a needle or the need to permanently puncture the tubular member  30 . In one embodiment, the sample valve  50  is sealed with a molded silicon rubber plug  51 . The plug  51  comprises a slit  55  which travels its length. In one exemplary embodiment, a syringe with a Luer lock tip (not show) may be mated with sample valve  50 . A standard syringe Leur lock tip (not shown) generally comprises a female threaded end surrounding a plastic tapered tip. In one exemplary embodiment, the syringe female threaded end is twisted onto the threaded sample valve  50 . The plastic threaded tip fits between the slit  55  and then enters sample volume  52 . The slit returns to the closed position when the syringe is twisted off the sample valve  50  (i.e., after withdrawal of a urine sample) and the tapered tip is removed. 
     Referring again to  FIG. 1B , the inlet chamber  32  and outlet chamber  34  are separated by valve element  60 . Valve element  60  serves as a backflow prevention device and blocks the movement of possibly contaminated urine from the collection container back into the catheter. 
       FIGS. 3 and 4  illustrate two exemplary embodiments of the of the valve element  60 . As shown in  FIG. 3 , valve element  60 A is in the form of a truncated cone  62  incorporating a slit  64  in the valve face  65 . This type of valve element is often referred to as a “duckbill” valve. The valve  64 B illustrated in  FIG. 4  utilizes a “cruciform” shaped geometry incorporating a slit  70  through the tip of a cone-shaped element  72 . Valves  60 A and  60 B open under positive pressure in the desired flow direction (indicated by arrows  74  and  76 ). At negative pressure differentials, valve elements  60 A and  60 B form positive seals at the slit locations  64  and  70 , thus preventing backflow of urine in the directions opposite of arrows  74  and  76  (i.e., towards the catheter tubing). The valves  60 A and  60 B are constructed of flexible, elastomeric materials such as, for example, silicone or fluoro-silicone elastomer. These materials are biocompatible and will not cause adverse reactions in the body. Valve elements  60 A and  60 B have low cracking (opening) pressures, for instance pressure less than about 0.03 psi. Thus, urine flow from the catheter tubing (not shown) through the inlet side  66  of the valve elements  60 A and  60 B is not impeded during normal urine production, maintaining unrestricted urine flow. The valves  60 A and  60 B are designed to prevent entrapment of solids as they pass to the collection container. Duckbill valve  64 A will pass solid objects, for instance as large as about 1.5 mm through slit  64 . In addition, valves  60 A and  60 B are designed to pass viscous liquids, for example up to about 3000 centipoise viscosity. The cruciform geometry embodied by valve  60 B ( FIG. 4 ) allows the passage of urine flow with a higher or larger solid content, for example solid objects with an equivalent diameter of one-half the interconnecting tube diameter, or approximately 3 mm. 
     The exemplary catheter valves  60 A and  60 B prevent backflow of potentially contaminated urine into the catheter in the event that the urine collection container is not maintained a height below the level of the bladder. The valves  60 A and  60 B will prevent backflow at pressure heads in excess of the height of the urine collection container. For example, the urine collection container may be lifted to a maximum of 8 ft. tubing above the catheter without backflow or reflux. 
     In an additional embodiment, the interior surfaces of tubular member  30  at the exit side  68  of valve  60  may be coated with at least one thin continuous layer of a substance with the ability to reduce the incidence of bacterial growth. In one embodiment, the interior surfaces of outlet chamber  34  at the exit side  68  of valve  60  and the internal and external surfaces of valve  60  are covered in at least one layer of a silver or silver alloy compounds. Other suitable materials may include platinum or other metals. Silver ions and silver alloy compounds show a toxic effect on some bacteria, viruses, algae and fungi, interfering with the reproduction process of the pathogen without toxicity to humans. The chemical properties of silver in the ionized form (Ag + ) produce the antimicrobial properties. Catheters utilizing silver alloy coatings are more effective than non-coated catheters for reducing bacteriuria in adults having short-term catheterization in hospitals. The valve will serve as a kill site for any reflux containing microbial material. 
     In an additional embodiment, the anti-backflow device  20  disclosed herewith further comprises an antimicrobial exit device  80 . In one embodiment as is illustrated in  FIG. 5 , the exit device  80  is constructed as a cylindrical polycarbonate cartridge containing a plurality of hollow internal passages  82  and external grooves  84  traveling its length. Unlike the exit device illustrated in  FIG. 1A , the exit device  80  illustrated in  FIG. 5  comprises a concave face  81  and exterior grooves  84 . This configuration of face  81  and grooves  84  increases the antimicrobial surface area available for interaction with the urine stream. Passages  82  and grooves  84  are also illustrated in  FIG. 6 , which shows a cross sectional view of the exit device  80 . The exit device  80  resides within the outlet chamber portion  34  of the tubular member  30 . It is to be understood that other embodiments of the exit device may exist. For instance, the outlet chamber portion  34  of the tubular member  30  may be filled with silver coated spheres. In one embodiment, the surfaces of exit device  80 , internal passages  82  and external grooves  84  are coated with a thin layer of an antimicrobial substance, such as a silver compound. As described above, the silver confers antimicrobial properties to the exit device due to the release of silver ions. The channels  82  and grooves  84  increase the surface area of the silver coated surfaces, allowing greater exposure of potentially contaminated urine to the antimicrobial silver coating. In addition, the large number of passages  82  and external grooves  84  allow for the steady flow of urine through the exit device  80  and prevents blockages caused by solids normally found in urine. Placement of the exit device  80  in the outlet chamber  34  acts to (1) kill residual bacteria in the urine travelling through the device from the catheter, and (2) eliminate bacteria from any urine reflux backflow from the urine collection container. Movement of urine into or out of the outlet chamber  34  must occur through the exit device  80 . 
     The anti-backflow device  20 , valve  60  and other devices described herein may be made by conventional methods as known by one of skill in the art. In one embodiment, the components are assembled using ultrasonic bonding, which leaves no residual bonding material. The antimicrobial coatings presently disclosed may be made by conventional methods as known in the art. In order to avoid the introduction of any microbes into device  20 , the device  20  and associated catheter and tubing may be sanitized using methods known in the art, for instance by autoclave, gas sterilization or irradiation methods. 
       FIG. 7  shows one embodiment of a catheter anti-reflux system  100  as presently disclosed. A urinary catheter  102  is utilized to assist in the removal of urine from a patient. The catheter  102  is connected to the device  20  inlet chamber  32  via rubber catheter tubing  104 . As discussed in detail previously, catheter tubing  104  is secured to the device via hose barb connection  38 . Device  20  prevents backflow of urine back into the catheter through the use of one-way valve  60 . In addition, the device  20  provides antimicrobial surfaces on the interior of the outlet chamber  34  as well on a large surface area exit device  80 . These structures function to kill any residual or refluxed bacteria. Finally, device  20  provides a urine sample volume  66  which may accessed from a needleless sample valve  50 , both or which are protected from backflow contamination. Urine collection tubing  106  is attached to the outlet chamber  34  by hose barb connection  39 . The urine collection tubing  106  leads to a urine collection container  108 . 
     In operation, the pressure of the urine flow emanating from a patient directs the urine through the catheter tubing  104  where it enters the anti-reflux device  20  at the inlet end portion  36 . The device  20  and the catheter tubing  104  are connected via hose barb connection  38 , thus preventing leakage. The exterior surfaces of hose barb connection  38  may be coated with an antimicrobial material to prevent contamination from occurring at this interface. The urine flow continues into the inlet chamber  32  of tubular member  30 , filling the sample volume  42 . A sample of fresh urine may be collected through the needless sample valve  50  by opening the non-puncture mechanism  51  and removing the urine. Sampling on the inlet side  66  of the valve element  60  prevents backflow of contaminated urine from the urine collection container and allows the sample to be representative of the true bladder output. The urine flows over the interior surfaces of the valve element  60  and reaches the outlet side  68  of the valve  60 . The cracking or opening pressure of the valve  60  is low, for example less than 0.03 psi, allowing the outlet side  68  of valve element  60  to open under normal urine flow pressure. 
     The urine flow travels through the outlet side  68  of valve element  60  and interacts with the antimicrobial coated interior surfaces of the outlet chamber  34 , which functions to kill any residual bacterial in the urine. The construction of the one-way valve element  60  prevents its opening and backflow of urine flow into the valve element  60 , the medial portion  33  of the tubular member  30  and into the catheter (not shown) at head pressures of up to, for example, 10 feet of water. The continuing pressure of the urine flow pushes the urine stream through the antimicrobial-coated passages  82  and external grooves  84  of exit device  80 . The large surface area provided by passages  82  and external grooves  84  ensure exposure of the entire urine stream to the antimicrobial coating. The urine flow then continues out of outlet chamber  34  of device  20  and into the tubing connecting the device  20  with the urine collection container  108 . The urine collection container tubing  106  and the device  20  are attached via hose barb connection  39 , thus preventing leakage. Any subsequent reflux of contaminated urine from the urine collection container  108  into the outlet chamber  34  will travel through the exit device  80  and will be exposed to the antimicrobial coated surfaces of passages  82  and external grooves  84 . The presently disclosed device and system prevents reflux from traveling the urine collection system back to the bladder through the use of a one-way check valve, provides an antimicrobial “kill” area for bacteria and other pathogens at the entrance to the catheter, and provides a sampling volume adjacent to the collection catheter which is isolated form the urine collection system.