Abstract:
A catheter connector for coupling to a catheter, the connector having a body part, a tubular shaped compressible plug situated in a bore in part, with the proximal end of the catheter insertable into the bore of the plug, and a lever pivotably mounted to the housing part. Pivoting of the lever applies an axial force on one end of the plug causing the plug to deform radially inward and tightly engage the proximal end of the catheter.

Description:
BACKGROUND OF THE INVENTION 
   This invention is in the field of catheter connectors wherein a catheter connector is coupled to the proximal end of a catheter. 
   Many catheters, including but not limited to epidural catheters, need to be coupled to catheter connectors situated near the insertion site on a patient. Such a connector secures the proximal end of a catheter from both axial and transverse movement, and often includes one or more fluid couplings for communicating fluids into or out of the catheter. 
   It is important for the surgeon and other medical personnel to be able to make this coupling of the connector with the proximal end of the catheter quickly, easily and securely. Also it is desirable for the connector to be relatively inexpensive, if possible, since these are often disposable, non-reusable devices which adds to the already expensive cost of invasive medical procedures. 
   The objects of coupling securely, quickly, easily and economically often call for design features that are in conflict with each other. With regard to a secure coupling that bars axial or transverse movement of the catheter, prior art devices usually apply inward radial compression to one or more outer surface areas of the catheter; however, excessive pressure will collapse the soft tubular catheter and at least partially close the inner fluid passageway, and insufficient pressure will not hold the catheter securely. 
   This coupling is necessarily a manual event by the user&#39;s hands and fingers. Thus, even if the user were able to apply the ideal amount of compressive force on a catheter on one occurrence, such would not necessarily happen on the next occurrence. It is most difficult for users of these devices to always select the correct gripping force in the many various medical procedure circumstances and in the extremely limited time to make the decision. 
   In addition to the above-described objective of securely engaging the catheter, the coupling procedure needs to be easy and quick. There is little time for a doctor or nurse to adjust and/or study the device. 
   Numerous prior art devices apply inward radial force on the catheter by simply pressing inward with a rigid element of the connector. Such force is applied to one specific outer area, or is applied circumferentially around the catheter outer wall by a compressible collar surrounding the catheter. In the latter case the compressible collar is situated coaxially within the bores of a pair of mating sleeves which are threadedly engaged. When these sleeves are screwed together, they apply axial force to the collar that is then deformed radially inward against the catheter. Such rotation of one sleeve relative to another necessitates use of two hands by the operator. Such two-handed operation requires time and coordination, and as discussed above, the user is unlikely to be able to apply the same force every time. Of the many prior art catheter connector devices which use threaded elements to achieve deformation of a plug through which a catheter extends, U.S. Pat. No. 5,464,400 to Collins illustrates male and female coupling elements which axially compress a hexagonal slug. As with other threaded couplings, two hands are required; there is no contemplation of operating this device with one hand or of designing any device for such operation. 
   Another typical prior art connector structure having telescoping sleeves threaded for rotation by a two-handed operation that compresses a collar 15 is seen in U.S. Pat. No. 6,260,890 to Mason. 
   U.S. Pat. No. 6,228,059 to Hoffman shows a still different locking means, for a trocar, where a locking element 58, as seen in FIGS. 2 and 3, bears down at one area on the side wall of instrument 34. U.S. Pat. No. 6,096,024 to Graves et al. shows a pivoting latch which engages the side wall of a needle cannula. U.S. Pat. No. 5,931,671 to Hoffman discloses a pair of compression elements that move transversely inward to releasably engage and hold a central tube. 
   This long-practiced concept of applying lateral force directly to a central tube or element is seen most clearly in U.S. Pat. No. 5,725,504 to Collins, where a simple cam lever 28 pivots to engage and deflect wall 27 against hub 12. 
   The prior art devices described above demonstrate that the long-established modes to secure a central shaft, whether it is a rigid or soft tube or shaft, are either: (a) to use a pivot lever to apply an inward radial force directly onto the side wall of the central shaft, or (b) to use a pair of threaded sleeves, rotatable by a two-handed operation, to apply an axial force to a collar which in turn applies an inward radial force to a central tube. 
   The more extensive use of catheters and the more intricate surgical procedures has led applicants to an approach which utilizes some known elements and combines them in a new and most useful way. The present invention seeks to overcome all of the above-described faults and disadvantages in prior art catheter connectors with a new device that allows coupling to be secure, quick, easy, uniformly applied and achievable with a single hand. 
   SUMMARY OF THE INVENTION 
   The new catheter connector uses a pivoting lever to create and apply an axial force to an elastically deformable collar or plug which is enclosed on its outer circumferential and opposite end surfaces, and can deform radially inward. Furthermore, this inward force is generally uniform all the way around the catheter&#39;s outer surface, which reduces the possibility of an extreme localized force that would collapse the catheter. A still further benefit is that the axial compression is affected along the length of the plug and then radially inward, which distributes the force over a very wide surface area of the catheter. This creates a very large frictional force to capture and hold the catheter from any axial or transverse movement with minimal danger of collapse. 
   Also, the lever action allows the user, with a quick simple motion, to make the coupling and to apply the same correct force to the catheter every time. This is possible since the lever moves through the same arc, and its shoulder moves the same axial distance every time. 
   Also, this device can easily be operated to open or close with a single hand, by flipping a finger or thumb. 
   A second embodiment of the invention disclosed herein utilizes a collar or plug with flats on the outer surface. In cross-section such a plug could be, for example, hexagonal or octagonal, where the maximum outer diameter would be between two opposite points and the minimum outer diameter would be between two opposite sides or flats. An alternative could be essentially round outer diameter with intermittent flats, where the maximum outer diameter would be between two opposite outer circular arc segments and the minimum outer diameter would be between two opposite sides or flats. Such a plug is situated generally snugly within a circular bore of a sleeve such that when axial force is applied to such plug, it deforms radially outward in the areas of the flats; however, the bore walls bar the plug from further outward deformation, and thus further axial force causes the plug to deform radially inward against the catheter. 
   In both of the above-described embodiments the application of axial force to the tubular plug is achieved by a lever pivotally mounted on the connector housing. Such lever pivots about an axis perpendicular to the central longitudinal axis of the catheter and of the connector, and a shoulder of the lever applies the axial force to the plug or to a plunger or annular pressure element contacting the end of the plug. Such lever can easily be pivoted by a user&#39;s thumb while he grips and holds the connector body with his palm and fingers. 
   This axially compressed plug resiliently urges the lever to return to its open position, but a latch is provided to hold the lever in its pivoted and closed position, until released. The latch is established by projections on the lever and mating recesses in the connecting body, or vice versa. In a preferred embodiment a portion of the body which includes the recesses is axially slidable against a spring element thereon, to effect release of the lever. This manual step can also be done by one hand of the user. Upon release, the lever pivots to its open position because of the compressed plug in contact with the lever, and the catheter is then released. 
   This disclosure herein shows two preferred embodiments of lever and connector body construction, with the understanding that numerous variations are possible. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a top front perspective view of the new catheter connector with its lever in closed position, 
       FIG. 2  is a longitudinal sectional view taken along line  2 — 2  in  FIG. 1 , 
       FIG. 2A  is an enlarged fragmentary sectional view of a portion of  FIG. 2 , 
       FIG. 3  is a transverse sectional view taken along line  3 — 3  in  FIG. 1 , 
       FIG. 4  is an exploded perspective view of the connector of  FIG. 1 , 
       FIG. 5  is a top front perspective view of the new catheter connector of  FIG. 1  with the lever in open position, 
       FIG. 6  is a longitudinal sectional view taken along line  6 — 6  in  FIG. 5 , 
       FIG. 7  is a partial transverse sectional view taken along line  7 — 7  in  FIG. 1 , 
       FIG. 8  is a top plan view of a second embodiment of the new catheter connector with the spring latch and the lever in closed position, 
       FIG. 9  is a longitudinal sectional view taken along lines  9 — 9  in  FIG. 8 , 
       FIG. 10  is an exploded perspective view of the connector of  FIG. 8 , 
       FIG. 11  is a top plan view of the connector of  FIG. 8  with the spring latch and lever in open position, and 
       FIG. 12  is a longitudinal sectional view taken along line  12 — 12  in  FIG. 11 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1–7  illustrate a first embodiment  10  of the new catheter connector, which has open and closed positions, as will be explained below. The principal components as best seen in  FIGS. 1 and 4  are the connector body  12 , spring latch  14 , pivot lever  16  with its arm  16 A and lever body  16 B, compressible elastically deformable plug  18  and plunger  20 .  FIG. 10  shows another embodiment  18 A of the compressible plug, the latter being circular in cross-section. Plugs having hexagonal, octagonal and other cross-sections are interchangeable.  FIG. 1  also shows catheter  22  coupled to connector  10 . 
   As further seen in  FIGS. 1–7  and particularly in  FIG. 4 , the body  12  is an elongated member having a central bore  24 , a first longitudinal ledge  26 , threaded proximal end  28 , recess  30  to receive the lever body  16 B, recess  32  to receive the lever arm  16 A, and recess  34  to receive the lever pivot pin  16 P.  FIG. 2  further shows lever shoulder  16 S at angle ∝ of 45° that abuts stop  20 S of connector body  12 . 
   A general description of the operation of this device, which will be later described in detail, is as follows. Beginning with open position seen in  FIGS. 4 ,  5  and  6 , the proximal end of catheter  22  is inserted through rigid plunger  20  into the bore of compressible plug  18  which is already situated in bore  24  of body  12 . Next, lever arm  16 A of lever  16  is pivoted counterclockwise until (as seen in  FIG. 2 ) its compression edge  16 C applies an axial force to the left, onto rigid plunger  20 , which applies such axial force onto the end of compressible plug  18 . This plug is generally confined in bore  24  of body  12  and then deforms radially inwardly against the outer circumferential body of catheter  22 . To be described later latch spring means retains this lever in its closed position until released. 
   As seen in  FIGS. 1–6  and  2 A, the lever  16  has its pivot pin  16 P engaged in body recess  34  (see  FIG. 4 ), its body  16 B in body recess  30  and its arm  16 A in recess  32 . This lever arm  16 A is pivotable clockwise to its open position seen in  FIGS. 2A ,  5  and  6 , where the lever shoulder  16 S abuts bottom surface  20 S of plunger  20  which limits the lever from pivoting beyond the 45° angle shown. 
   The next principal element is compressible plug  18  made of foam rubber or comparable material. This plug is a tubular member having a bore diameter adapted to easily receive catheter  22  and an outer diameter adapted to easily fit into bore  24  of body  12 . This plug has length such that when its proximal end abuts the proximal end of bore  24 , its distal end will engage plunger  20 . Since plug  18  is confined by bore side and end wall surfaces, an axial force of plunger  20  applied to the distal end of plug  18  will compress and cause it to deform radially inward against the proximal end of catheter  22 . 
   The deformed plug will apply radial inward force along the length of the plug around the circumference of catheter  22 , thus snugly capturing it from axial or transverse movement. The forces applied will securely engage the catheter without collapsing it, and essentially the same force will be applied each time, regardless of who the user is. These forces will be essentially the same because lever  16  pivots through the same arc each time it moves to its closed position and plunger  20  moves the same axial distance, this distance being further governed by shoulder  20 X on plunger  20  as seen in  FIG. 2  being stopped by shoulder  12 X of body  12 . 
   As noted earlier, the plug may have a variety of cross-sections and still achieve the same general functions. Thus, the plug may be circular as seen in  FIG. 10 , or may have flats as seen in  FIG. 4 , or may be hexagonal, octagonal, or may have other irregular shapes, so long as it deforms or compresses radially inward when axially compressed. 
   It has been found that forming flats on the outer surface of the plug established some areas or zones which have outer diameter conforming generally to the bore or inner diameter  24  of the connector body and intermittent areas or zones of the plug&#39;s outer surface which have smaller outer diameter. These latter areas will deform radially outward before the plug deforms radially inward against the catheter, because these outer areas are adjacent air space which poses no resistance. After this initial outward deformation, the plug is snugly confined and set in its position, and it will then deform radially inward, generally uniformly around the engaged length and outer circumference of the catheter. The plug&#39;s outer diameter may initially fit snugly within the bore or it may have clearance. 
   The plug illustrated in  FIG. 4  has six uniformly spaced flats, each two adjacent flats being separated by a longitudinal zone of arcuate circular diameter that is the maximum diameter of the plug and corresponds to the bore diameter  24  of body  12 . The diameter between any two opposite flats is the minimum diameter of the plug and is the area where the principal radial outward deformation of the plug will occur. The plug is preferably uniform in cross-section along its length; however, the cross-section may also vary along the length. 
   As seen in  FIG. 6 , the plunger  20  has a proximal end to apply axial force to most of the exposed end of plug  18 , and has a distal end with a conical recess to easily receive the proximal end of the catheter  22  when inserted. Also, pivot body  16 B has a divergent opening  16 D as seen in  FIGS. 1–2  and  4 – 6  to allow pivoting while the catheter extends therethrough. 
   Spring latching of lever  16  is achieved as follows. As seen in  FIGS. 1–6  spring latch  14  is a generally cylindrical member having a longitudinal slot  40  at the top, a central recess  42  (see  FIG. 3 ), a longitudinal tooth  44  extending radially inward on both sides (see  FIGS. 3 and 4 ), and a longitudinal recess  46  extending outward on both sides (see  FIGS. 3 and 4 ). This member  16  further includes spring fingers  48  which are deflectable axially to the left, which then urge latch member  14  to move to the left. As seen in  FIGS. 4 and 5  pivot arm  16  has latch tabs  16 L which cooperates with latch recesses  46  in latch  14  (seen in  FIGS. 3 and 4 ) as follows. 
   The normal position latch  14  is to the left as seen in  FIG. 1  due to the spring force applied to the left by latch spring fingers  48 . This latch is manually movable to the right (distally) when a user grips the latch, preferably by the ribbed surface and slides it distally to the right. When the lever arm  16 A is down in closed position of  FIGS. 1–3  with the catheter constrained as described above, latch  14  is spring biased to the left where its outward recesses  46  have received and hold projections  16 L of the lever arm and thus restrain this arm from pivoting clockwise back to its open position which would release the catheter. Manual sliding of the latch releases the lever arm, and the compressed plug then urges the lever to pivot to the open position. This quickly and automatically releases the catheter, this release being achieved by a simple finger or thumb action of a single hand of the user. 
   As seen in  FIG. 3 , the latch  14  remains coupled to the body  12  by the fact that its longitudinal teeth  44  overlie and slide against shoulder  26  of body  12 . This latch is resiliently spread open to slide transversely onto body  12  until the teeth  44  snap onto shoulder  26 . The latch is thus coupled onto the body  12  but free to be slid axially by the user. 
   As seen in  FIG. 5 , the distance of travel L1 of the latch  14  is greater than the length L2 of the lever arm projection  16 L, so that axial motion of latch  14  will uncover and release the lever arm; however, until manual release of latch  14 , the lever will remain safely locked. 
     FIGS. 8–12  illustrate a second embodiment of the catheter connector, generally similar to the first and which will bear identical reference numbers for all elements except those few where there are differences. The first difference is that the lever pivot pin and pivot pin recess are reversed. The first embodiment in  FIG. 4  shows pin  16 P on the lever  16 , whereas the second embodiment has pivot pin  52  on body  12 . Similarly, the first embodiment in  FIG. 4  shows the pivot pin recess  34  on the body  12 , whereas the second embodiment in  FIG. 10  shows the pivot recess  50  on lever  16 . 
   Next, the stop or shoulder  16 S of  FIG. 2  is not present in the second embodiment in  FIG. 12 . Also, the ledge or shoulder  26  of body  12  mating tooth  44  of latch  14  are not present in the second embodiment connector of  FIG. 10 . 
   The components of the new catheter connector are made by manufacturing methods long known in the relevant prior art and typically of injection molded plastic. 
   The invention maybe embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.