Abstract:
A flash chamber having a self-closing valve for use with a catheter is described. The flash chamber, which is connected to the catheter, precludes blood leakage as a needle is removed from the catheter and an IV unit is coupled to the catheter. The flash chamber permits the practitioner to visually verify that a blood vessel has been punctured and includes a self-sealing valve that prevents blood from flowing out of the flash chamber as the needle is removed and the IV unit is attached.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application claims priority from U.S. Provisional Application Ser. No. 60/208,690, filed Jun. 1, 2000, which application is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     The present invention relates to a flash chamber with a self-closing valve for use with a catheter. The flash chamber precludes blood leakage as a catheter needle is removed from the catheter and an IV unit is coupled to the catheter. 
     Intravenous (IV) procedures are commonly used in the medical arts to deliver medications and other fluids to patients. Typically, the IV procedure is initiated by having a needle encircled by a catheter or plastic sleeve pierce a patient&#39;s skin. The needle and catheter are then inserted into a vein or artery to provide the practitioner with access to the circulatory system. The needle is then removed from the catheter, and an IV line is attached to a terminal hub. 
     When the needle, which is commonly attached to a syringe, is within the catheter a positive pressure is applied against the blood coursing through the punctured vein or artery so that blood remains in the blood vessel. However, once the needle is removed from the catheter and before the IV line is attached to the hub blood can freely flow from the punctured vessel through the catheter. The blood exiting the catheter obscures the working area and exposes the practitioner to direct contact with the patient&#39;s blood. 
     Because intravenous procedures are so common and important in the medical arts, it would be advantageous to have an IV catheter assembly designed to keep the blood from exiting through the catheter when the needle is removed and before the IV line is attached. Preferably the design should be relatively simple, thereby reducing the possibility of a failure of the system, and should be capable of being used with the current IV lines without the need for adapters. 
     SUMMARY OF THE PREFERRED EMBODIMENT 
     The present invention is for a flash chamber with a self-closing valve for use with a catheter. The flash chamber precludes blood leakage as a needle is removed from the catheter and an IV unit is coupled to the catheter. The flash chamber is connected to the catheter, and is adapted to receive the IV line. The flash chamber permits the practitioner to visually verify that a blood vessel has been punctured and includes a self-sealing valve that prevents blood from flowing out of the flash chamber as the needle is removed and the IV unit is attached. A stylus extends into the flash chamber and is positioned such that the stylus can be made to protrude through the valve placing the catheter in fluid communication with the IV unit. 
    
    
     DESCRIPTION OF FIGURES 
     FIG. 1 is a perspective view of a catheter assembly including a flash chamber with a self-closing valve made in accordance with the present invention; 
     FIG. 2 is a cross-sectional side view of the catheter assembly of FIG. 1 with the stylus withdrawn and the pathway closed; 
     FIG. 3 is a cross-sectional side view of the catheter assembly of FIG. 1 with the stylus protruding through the diaphragm, thereby leaving the pathway open; 
     FIG. 4 is a cross-sectional side view of the catheter assembly of FIG. 1 with the stylus protruding through the diaphragm and with a needle protruding through the catheter; 
     FIG. 5 is cross-sectional side view of the catheter assembly of FIG. 1 with the stylus removed from the diaphragm and with a needle protruding through the catheter; 
     FIG. 6 is a cross-sectional side view of the first housing of the flash chamber; and 
     FIG. 7 is a cross-sectional side view of the second housing of the flash chamber. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The catheter assembly including a flash chamber with a self-closing valve depicted in the various Figures is selected solely for the purposes of illustrating the invention. Other and different catheter assemblies and flash chambers may utilize the inventive features described herein as well. 
     Reference is first made to FIGS. 1 through 5 in which the catheter assembly including a flash chamber with a self-closing valve constructed in accordance with the present invention is generally noted by the character numeral  10 . The catheter assembly  10  has as major components a flash chamber  14 , a self-closing valve  50 , and a catheter  12 . The catheter  12  is a hollow sleeve  11  with a hub  13 , as is known in the art. The self-closing valve  50  is a diaphragm with sufficient resiliency that fluids, such as blood, cannot leak through the slit when it is closed. In a preferred embodiment, the diaphragm  50  is made of self-sealing elastomeric materials so that the diaphragm “closes” when it is in a resting state. Further, in a preferred embodiment, the diaphragm  50  is pre-slit minimizing the risk of creating shreds from the diaphragm material as the catheter  12  and needle are forced through the diaphragm  50 . 
     As shown in FIGS. 2-7, the flash chamber  14  includes a first housing  20  and a second housing  30 . The housings  20 ,  30  can be manufactured from any material which can be produce a semi-rigid device and which can retain the shape of the device during sterilization procedures. Because the practitioner may wish to see blood flowing into and through the housings  20 ,  30 , optionally, the housings  20 ,  30  can be manufactured from an essentially translucent material. However, translucency of the material is not required for the flash chamber to function as intended. 
     The first housing  20  has a receiver end  22  which is adapted to reversibly receive the catheter  12 , and a valve end  24  which is threaded  28  on the exterior surface. An essentially centered bore  26  extends longitudinally through the housing  20  from the receiver end  22  to the valve end  24 . When the catheter  12  is attached to the first housing  20 , as shown in FIGS. 2-5, the bore  26  is in fluid communication with the catheter sleeve  11 . The bore  26  has a port or a section with an enlarged diameter  27  at the valve end  24  proportioned such that the self-sealing valve or diaphragm  50  can fit snuggly within the port  27 . 
     As shown in FIGS. 2-7, the second housing  30  has an attachment end  32  with a threaded core  31 , a connector  34 , and a stylus  36 . The attachment end  32 , and more particularly the threaded core  31 , is adapted to engage the threads  28  of the valve end  24  of the first housing  20 . The threaded core  31  has sufficient length that the threads  28  of the first housing  20  can be screwed into the core  31  until the attachment end  32  of the second housing  30  abuts the receiver end  22  of the first housing  20  as shown, for example, in FIG.  2 . The connector  34 , which extends outward from the second housing  30  away from the threaded core  32 , is adapted to receive a standard luer-lok syringe or intravenous (IV) tube connection, as are known in the art. The stylus  36  projects from the connector  34  into the threaded core  32  and has an essentially centered bore  38 . As shown in FIGS. 4 and 5, near the threaded core end of the stylus, the bore  38  has a diameter sufficient to receive an injection needle  92 . Near the connector end, the bore  38  is enlarged to allow the needle end  94  of a syringe  90  to be received within the bore  38 . 
     The first housing  20  is attached to the second housing  30  by engaging the threads  28  of the valve end  24  with the threaded core  31  of the attachment end  32 . As shown in FIGS. 3 and 4, the housings  20 ,  30  can be tightened until the first housing  20  abuts the second housing  30 , and the stylus  36  protrudes through the diaphragm  50 . This defines an “open” position for the catheter assembly  10 , with the stylus bore  38  in fluid communication with the first housing bore  26  and the catheter  12 . When the catheter assembly  10  is open, fluids can flow through the intravenous tubing into the flash chamber  19 , then into the catheter  12 , and then into the patient&#39;s circulatory system. Because the stylus  36  is in direct contact with the diaphragm  50 , it is preferable but not required that the stylus  36  be slightly blunted so that the stylus  36  does not scratch rubber shreds from the diaphragm  50 . 
     As shown in FIGS. 2 and 5, the catheter system  10  also has a “closed” position in which the first housing  20  is separated from the second housing  30  such that a space or gap  60  remains between the receiver end  22  and the attachment end  32 . In the closed position, the housings  20 ,  30  are sufficiently separated so that the stylus  36  does not penetrate the diaphragm  50 . As shown in FIG. 5, the stylus  36  can be removed from the diaphragm  50  but the needle  92  can remain in position through the diaphragm  50 . This allows the diaphragm  50  to partially close and to form a seal around the needle  92 . Then, the needle  92  can be removed allowing the diaphragm  50  to completely close, or seal, preventing blood from moving beyond the flash chamber  14 . The sequential removal of the stylus  36  and then the needle  92  is not necessary for the diaphragm  50  to seal as intended, but by allowing the diaphragm  50  to close in two stages, the risk of blood leakage is further reduced. With the stylus  36  and needle  92  removed and the diaphragm  50  closed, blood can flow into the centered bore  26  allowing visual identification that the patient&#39;s blood vessel has been properly punctured. However, the blood can move no further than the diaphragm  50 . In a preferred embodiment, when the catheter assembly  10  is closed, the stylus  36  abuts but does not penetrate the diaphragm  50 . The presence of the stylus  36  creates a slight pressure against the diaphragm  50  to help keep the slit closed, thereby minimizing the risk of blood leakage through the diaphragm  50 . 
     Because time can be critical in many medical procedures, particularly when an intravenous line is being inserted, it is advantageous to have a catheter assembly  10  that is easy to use. In an embodiment, the first housing  20  and second housing  30  are oriented such that by rotating the second housing  30  about 90° relative to the first housing  20  the catheter assembly  10  moves from the closed to the opened position. Thus, when an IV line is connected to the connector  34 , simply rotating the second housing  30  slightly closes the gap  60  and initiates flow from the IV source to the patient&#39;s blood vessel. Optionally, stops or barricades which are known in the art may be added to the threaded core  32  and the threads  28  to limit the relative rotation of the housings  20 ,  30  although such stops are not required to allow the catheter assembly to function as intended. Further, optional fins  29 ,  39  may be added to the first and second housings  20 ,  30  to provide an easier finger grip for the practitioner. The fins  29 ,  39  can make it slightly easier to rotate the second housing  30  relative to the first housing  20 , but the fins  29 ,  39  are not a required element of the catheter assembly  10 . 
     In use, the catheter assembly  10  is prepared by attaching the catheter  12  to the first housing  20  of the flash chamber  14 . The assembly is then opened by rotating the second housing  30  relative to the first housing  20  so that the stylus  36  protrudes through the diaphragm  50 . With the diaphragm  50  forced open, the needle  92  and its associated guidewire  96  are inserted through the stylus  36  and through the catheter  12 . The needle  92  is then used to puncture the patient&#39;s skin, and is positioned within the vein, or within the artery with the aid of the guidewire  96 , as is known in the art. The second housing  30  is then turned to the closed position to form the gap  60 . Preferably, this action is completed before removing the needle  92 , as shown in FIG.  5 . By removing the stylus  36  from the diaphragm  50 —that is, by opening the gap  60 —and then retracting the syringe  90  and needle  92  from the catheter assembly  10 , the diaphragm  50  can close completely as the needle  92  is removed preventing the backflow of blood. The IV line can then be connected at the connector  32 , the second housing  30  turned to close the gap  60  forcing the stylus  36  through the diaphragm  50 , and the fluid flow initiated. In practice, because of the natural turning actions required to remove the syringe  90  and to connect the IV line with the connector  32 , the stylus  36  tends to be removed from the diaphragm  50  as the syringe  90  is removed and it  36  is forced through the diaphragm  50  as the IV line is connected. In an alternative embodiment, the needle  92  and guidewire  96  may be supplied already inserted through the catheter assembly  10 . In this case, the practitioner can simply insert the catheter in the patient&#39;s vein or artery and proceed as above. 
     It is understood that, in light of a reading of the foregoing description and drawings, those with ordinary skill in the art will be able to make changes and modifications to the present invention without departing from the spirit or scope of the invention, as defined herein. For example, although the embodiments presented herein anticipate that the first housing is threaded and the second housing is adapted to receive the threads of the first housing, other means which function to keep the housings together and that allow for relative axial movement between the housings may be used.