Abstract:
An anti-shock system for a catheter line inserted in a patient&#39;s body. The system includes a spring structure, a base and cover forming a housing with a catheter line entry port and exit port, the spring structure disposed within the housing. A first portion of a catheter line is positioned within the housing, with a distal end portion extending out the exit port, and a body entrance portion extending from the entry port. The spring structure is operatively coupled to a loop of the line and configured to absorb a pulling force exerted on the distal end by a spring action on the loop, without transmitting the pulling force directly to the body entrance portion of the catheter line and thereby prevent undesired migration of the catheter line within the patient&#39;s body.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/145,718 filed Apr. 10, 2015, the entire contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    Catheters are used, for example, to deliver medications or devices into a patient&#39;s body, or remove fluids or matter from the body. Peripherally inserted central catheters (PICC or PIC lines) are a common example, and are used for intravenous access over a prolonged period of time. PIC lines and catheters can be used to deliver chemotherapy, antibiotics or other medicines or nutrients to a patient, or to allow fluids to exit the body. 
         [0003]    A problem with catheters such as PIC lines is to maintain the position relative to the body, since the catheters are susceptible to inadvertent tugging or pulling which might tend to cause the line to migrate, i.e. to pull the line out of the body by some distance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    Features and advantages of the disclosure will readily be appreciated by persons skilled in the art from the following detailed description when read in conjunction with the drawing wherein: 
           [0005]      FIG. 1  is a diagrammatic view illustrating a PIC line as emerging from an insertion point in a patient&#39;s arm, with an exemplary embodiment of an anti-shock system for the PIC line. 
           [0006]      FIG. 2  is an exploded view illustrating features of an exemplary embodiment of an anti-shock system. 
           [0007]      FIGS. 2A and 2B  are views of the wheel structure of the embodiment of  FIG. 2 . 
           [0008]      FIG. 3  is an isometric view of the system of  FIG. 2  with the catheter line in assembled form and the system cover removed. 
           [0009]      FIG. 4  is an isometric view of the system of  FIG. 2  in assembled form. 
           [0010]      FIG. 5  is an exploded, isometric view of an alternate embodiment of an anti-shock system for a catheter. 
           [0011]      FIG. 6  is an isometric view of the system of  FIG. 5  in assembled form. 
           [0012]      FIG. 7  is an isometric view similar to that of  FIG. 6 , but with the cover removed. 
           [0013]      FIG. 8  is an isometric view of a further embodiment of an anti-shock system for a catheter. 
           [0014]      FIG. 9  is a view similar to  FIG. 8 , but with the top cover removed to show the wheel structure and arrangement of the tubing. 
           [0015]      FIG. 10  is an isometric exploded view of the system of  FIGS. 8 and 9 . 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    In the following detailed description and in the several figures of the drawing, like elements are identified with like reference numerals. The figures may not be to scale, and relative feature sizes may be exaggerated for illustrative purposes. 
         [0017]      FIGS. 1-4  illustrate an exemplary embodiment of an anti-shock system  50  for a catheter such as a PIC line  20 . The PIC line  20  is inserted into a patient&#39;s blood vessel at a body insertion point  12  in the patient&#39;s arm  10 , in this example, and run into a blood vessel to terminate at a desire point in the patient&#39;s body. A fitting  22  at a distal end of the line  20  provides a connection to a device or system for delivering a therapy intravenously to the patient through the PIC line  20 . The insertion point is typically covered by clear or translucent adhesive tape  16 . 
         [0018]    In the absence of the anti-shock system  50 , it is apparent that the catheter  20  is susceptible to pulling or tugging on the line, typically at or adjacent the distal end. This can occur inadvertently, e.g. when the line is disconnected from the delivery system. Pulling on the catheter can cause the catheter to migrate, i.e. to move the catheter within the blood vessel, with the interior end moved away from a desired therapy point in the patient&#39;s body. Conventionally, stabilization devices have been employed to secure the catheter to the patient&#39;s skin using aggressive adhesive materials. These devices can be difficult to remove without damaging the patient&#39;s skin, and also can allow tugging on the line at its distal end from applying pressure at the insertion point, since the skin itself can move in relation to underlying body structures and the blood vessel in which the catheter is inserted. 
         [0019]    In accordance with aspects of the invention, the PIC line is connected, or travels through, an anti-shock system  50 , more fully illustrated in  FIGS. 2-4 . The system  50  utilizes a spring action on a length of the catheter formed in a loop, so that the loop can absorb forces pulling on the distal end of the catheter without transmitting the pulling force directly to the insertion point. 
         [0020]    The system  50  includes a housing formed by base  52  and a cover  54 , which may be fabricated by injection molding of a plastic material such as ABS. The base  52  has opposed peripheral slots  52 A,  52 B which provide ports for entry and egress of the catheter line  20  from the system. The base has a central opening and boss  52 C, with a slot  52 D in the boss. A slot opening  52 E is formed in the base and communicates with the central opening in the boss. The boss is configured to receive the lower portion  56 F of the hub  56 A of wheel structure  56 , shown in further detail in  FIGS. 2A and 2B . The slot opening  52 E of the wheel structure is aligned with the slot  52 D in the boss  52 C. 
         [0021]    The wheel structure is fabricated from a material having some flexibility, such as Nylon or Delrin, for example. The wheel structure includes the hub  56 A which has open slot  56 . The engagement of the protrusion  56 A into boss  52 C in this exemplary embodiment is an interference fit, which prevents the wheel structure from rotating within the housing. In other embodiments, the engagement may be by different structures, for example a protrusion from hub  52 C fitting into a corresponding opening or recess in the boss  52 C. 
         [0022]    The wheel structure further includes curved or bowed spokes  56 C extending outwardly from the hub, terminating in fitments which define line receptacles. In this embodiment, there are five curved spokes terminating in fitments  56 D 1 - 56 D 5 , respectively, so that there are five receptacles  56 E 1 - 56 E 5 . The wheel structure is a unitary structure in this exemplary embodiment. 
         [0023]    The PIC line  20  has a loop  20 A formed in it, which is supported by the engagement of the line within the spoke receptacles  56 E. In this example, the line  20  enters the housing through port  52 A, and is connected in clockwise fashion to respective receptacles  56 E 1 ,  56 E 2 ,  56 E 3 ,  56 E 4 , with the tag end turned 90 degrees and directed toward the center hub  56 A. The line may be turned downwardly into the hub opening and then radially outwardly from the hub toward the exit port  52 B, where it exits the housing. The configuration in which the flexible line is formed is depicted in  FIG. 2  and in  FIG. 3 . The slot  52 E provided some clearance room for the adjacent portion of the line. 
         [0024]    The cover  54  is configured to fit onto the base  52 , e.g. in an interference fit, with  FIG. 4  illustrating the assembled condition. The hub  52 C of the wheel structure is captured between the base and the cover, and prevented from moving or rotating. 
         [0025]    In an exemplary embodiment, the receptacles at the distal ends of the curved spokes  56 C are configured to allow the line  20  to snap into the receptacle, with some frictional engagement. 
         [0026]    The system  50  further includes an adhesive layer  60  attached to the bottom surface of the base  52 , with a release cover layer  62  over laying the adhesive layer. The user may use tab  62 A to pull the release layer off the adhesive layer prior to application of the system to the patient&#39;s arm or other site. 
         [0027]    Now consider the situation in which a patient experiences a pulling or tugging on the distal end of the PIC line  20 , typically close to the fitting  22  end. The pulling force is transmitted by the line  20  to the loop  20 A and to the receptacles  56 D 5 - 56 D 1 , in turn tending to bend the curved spokes, rather than being transmitted to the line  20  at the insertion site  12 . The receptacles frictionally engage the line of the loop  20 A, so that the line does not slip through the receptacles when the line is tugged. Instead of migrating the line  20  within the patient&#39;s body, the tugging force is taken up by the spring action of the wheel structure  56  within the housing, allowing some portion of the line within the housing to be pulled out of the housing structure if the force is high enough. Once the tugging force is removed, the spring action of the wheel structure  56  will retract the line back into the housing structure. 
         [0028]    The portion of the catheter line  20  which extends toward the insertion point on the patient&#39;s body can be of sufficient length to serve as the portion of the catheter inserted into the patient&#39;s body. Alternatively, the portion may be terminated in a fitting, to allow connection to a separate catheter line end of the inserted catheter. 
         [0029]    An alternate embodiment of an anti-shock system  100  is illustrated in  FIGS. 5-7 . This embodiment includes base  102  and cover  104 , with adhesive layer  120  attached to the bottom exterior surface of the base to adhere the system to the patient&#39;s arm or other site. In this embodiment, a coil spring  114  takes the place of the wheel structure  56  of the embodiment of  FIGS. 1-4 . The spring is mounted between a stationary cleat  106  defined on base  102  and a slider  112  in turn mounted for sliding movement along slot  104  formed in base structure  102 . The loop  20 A′ formed in the catheter line  20  is fitted around the slider, a second fixed cleat  108 , and through cleats  110 . The line  20  is passed through entry port  104 A defined in the cover  104 , and through exit port  104 B. The entry port  104 A is configured to frictionally engage the line  20  to prevent it from slipping through the port as a pulling force is applied. Alternatively, another cleat can be provided just inside the base at the port  104  to engage the line and prevent its slippage. Also, the slider  112  may have a groove formed therein to receive the line and frictionally engage it, preventing slippage. 
         [0030]    Consider the situation in which the fitment end of the line  20  is pulled or tugged inadvertently. The pulling force will be applied to the slider  112 , drawing it toward the cleat  106  and tending to compress the spring  114 , allowing the distal end to pay out somewhat in reaction to the pulling force without applying tugging force to the line at the insertion point. Once the tugging force is removed from the line, the spring pushes the slider  112  back to the rest position, withdrawing the portion of line paid out back into the housing structure. 
         [0031]    The base  102 , cover  104  and slider  112  may be fabricated as plastic structures, typically by injection molding. The spring  114  may be a metal coil spring. Alternatively, other spring types may be used. 
         [0032]    A further embodiment of an anti-shock system  150  is illustrated in  FIGS. 8-10 . This embodiment is similar to the embodiment of  FIGS. 1-4 ; however, the base  52 ′ has straps  70 A,  70 B extending from opposite sides thereof, with a buckle or fastener  72  at the distal end of strap  70 A. The system  150  may therefor omit the use of an adhesive layer to secure the system to the patient&#39;s body. Thus, the system  150 ′ includes a base  52 ′, a removable cover  54 ′, and a wheel  56  as in the embodiment  50  of  FIGS. 1-4 . The base  52 ′ includes a boss  52 C′ with a slot  52 D′ formed in the boss. The wheel hub  56 F engages the boss as with the system  50 . The catheter line  20  is engaged with the fitments formed in the wheel  56 , as with the system  50 , and is passed from inlet port  52 A′, with a loop, and then back through the wheel hub and out the port  56 B′ of the base  52 ′. As with the system  50 , the wheel hub is prevented from rotation within the base, after the cover is attached. The hub  52 C of the wheel structure is captured between the base and the cover, and prevented from moving or rotating. 
         [0033]    The buckle  72  may use a pin (not shown) to enter one of the holes  70 B 1 , a clasp, or even hoop-and-loop or other type of fastener, allowing the straps to secure the base  52 ′ to the patient&#39;s arm or wrist. This may avoid the use of an adhesive to secure the system  150  to the patient&#39;s arm or wrist, and make removal more convenient to the patient while avoiding the risk of injury to the patient&#39;s skin. The straps could be sized to attach to the patient&#39;s arm above the elbow, or to the patient&#39;s forearm, or to the patient&#39;s wrist. Alternatively, or in addition, the back of the base  52 ′ may include a less aggressive adhesive layer than is used with the system  50 . 
         [0034]    Once the system  150  has been attached to the patient&#39;s body by use of the straps, the system  150  protects against migration of the line  20  within the patient&#39;s body in the same manner as described above with respect to system  50 . 
         [0035]    Although the foregoing has been a description and illustration of specific embodiments of the subject matter, various modifications and changes thereto can be made by persons skilled in the art without departing from the scope and spirit of the invention.