Abstract:
A catheter assembly includes a catheter adapter and an introducer needle. The introducer needle extends through the catheter adapter and through a catheter tube so as to assist placement of the catheter tube into a patient&#39;s blood vessel. Blood flashback into the catheter tube and/or catheter adapter through an aperture in a side of the needle indicates when the catheter tube is within the blood vessel. After the catheter tube is placed in the blood vessel, the introducer needle is withdrawn. A primary septum within the catheter adapter blocks blood flow in a proximal direction past the primary septum. A secondary septum proximal the primary septum is biased so as to enter into the aperture in the introducer needle and plug the aperture while the needle is being withdrawn, thus blocking blood flow through the aperture after the aperture is drawn through the primary septum.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The application claims priority to U.S. Provisional Application No. 61/911,944, which was filed on Dec. 4, 2013, the entirety of which is hereby incorporated by reference. 
    
    
     BACKGROUND 
     The present disclosure relates to the field of infusion devices, and more particularly to peripheral intravenous (IV) catheters. 
     A catheter assembly for an IV catheter generally includes a flexible catheter or catheter tube coupled to a distal end of a catheter adapter, which is also known as a catheter hub. The catheter adapter retains the catheter tube so that other components can interact with the catheter tube. In order to place the catheter tube in the patient&#39;s blood vessel, an introducer needle is coupled to the catheter adapter so that the needle extends through the catheter tube, with the sharp distal tip of the needle positioned just beyond the distal end of the catheter tube. The clinician uses the introducer needle to penetrate the patient&#39;s tissue and place the distal end of the catheter tube in a blood vessel. 
     Once the needle tip and the catheter tube are in the vessel, the clinician typically uses blood flashback to confirm that placement is correct. For example, the introducer needle can have an aperture, formed through its side proximal of its hollow tip. When properly placed in the vasculature of the patient, blood will flow into the tip of the introducer needle and out the needle notch. Typically the needle aperture is positioned within the catheter tube, and blood exiting the aperture will flow through the catheter tube and/or into a viewing portion of the catheter adapter. When the clinician sees the blood flow, the clinician knows that the distal tip of the needle and/or the distal end of the catheter tube is in place in the blood vessel. 
     During blood flashback, blood may accumulate in the catheter tube and catheter adapter. A septum in the catheter adapter contains the blood in a distal chamber of the catheter adapter. Once it is verified that the catheter tube is correctly placed in the blood vessel, the introducer needle is removed, and a source of IV fluids can be attached to the catheter adapter via a coupler. However, when the introducer needle is being removed there is a risk of blood flowing through the needle and exiting the needle aperture proximal of the septum. 
     SUMMARY 
     Accordingly, there is a need in the art for a catheter assembly which prevents or inhibits blood flow out of the aperture as the introducer needle is removed from the catheter tube. 
     In accordance with an embodiment, the present disclosure provides a catheter assembly, comprising a catheter adapter, a primary septum, an introducer needle and a secondary septum. The catheter adapter defines an internal space. The primary septum is within the internal space, and the primary septum divides the internal space into a distal chamber and a proximal chamber. The introducer needle extends through the primary septum. The introducer needle is hollow and has a distal tip and a notch formed in a side wall of the needle proximal of the distal tip. An aperture through the needle side wall is formed in the notch. The secondary septum is disposed in the proximal chamber. The secondary septum has a needle hole through which the introducer needle extends. The secondary septum is biased inwardly at the needle hole. The needle generally deforms the secondary septum radially outwardly at the needle hole. When the introducer needle is drawn proximally so that the needle notch enters the secondary septum needle hole, a portion of the secondary septum extends into the notch so as to plug the notch aperture. 
     In some embodiments the secondary septum can be configured so that after the secondary septum engages the needle notch, the secondary septum moves proximally with the needle. 
     Further embodiments can additionally comprise a detent arranged proximal of the secondary septum in the proximal chamber. The detent is configured to exert a distally-directed force on the secondary septum as the introducer needle is drawn proximally so as to oppose proximal movement of the secondary septum. 
     In some such embodiments, when the portion of the secondary septum extends into the notch, a distal face of the secondary septum can engage a distal end of the notch so that a portion of a proximally-directed force applied to the introducer needle is communicated to the secondary septum distal face. In additional embodiments, the portion of the proximally-directed force can be greater than the distally-directed force exerted by the detent. 
     In additional embodiments the secondary septum can be configured so that when the portion of the secondary septum extends into the notch, a corresponding portion along a circumference of the secondary septum moves radially inwardly so that the distally-directed force exerted by the detent is reduced or eliminated. 
     Some embodiments can additionally comprise a septum activator within the proximal chamber, and the secondary septum can be supported within the septum activator. In some such embodiments, the septum activator can have a proximal opening, and a radius of the proximal opening can be greater than a radius of the secondary septum. 
     In yet other embodiments, the secondary septum needle hole can be biased inwardly at a flat portion that lies flat when in a relaxed condition, and the needle notch can be aligned with the flat portion. 
     In still further embodiments, the secondary septum can comprise a rigid latch insert configured to move radially outwardly when the needle hole is radially expanded. In such embodiments, the secondary septum can be supported on a mount, and the mount can comprise a latch receiver configured to selectively receive a distal portion of the rigid latch insert. The latch receiver can have a stop configured to block the distal portion of the latch insert from moving proximal past the stop when the distal portion of the latch insert is received in the latch receiver. 
     In accordance with another embodiment, the present disclosure provides a medical method. The method initially comprises providing a catheter assembly comprising a catheter adapter defining a distal chamber and a proximal chamber separated by a primary septum. A secondary septum is positioned proximal the primary septum and in the proximal chamber. The catheter adapter has a catheter tube extending distally therefrom, and an introducer needle extends through the secondary septum and the catheter tube. The introducer needle has a notch formed in a side wall. The method additionally comprises pulling the introducer needle proximally relative to the catheter adapter and the secondary septum. A portion of the secondary septum enters the notch when the notch passes through the secondary septum so that the secondary septum plugs an aperture formed in the notch. After the portion of the secondary septum enters the notch, the introducer needle is pulled proximally relative to the catheter adapter, and the secondary septum moves proximally with the introducer needle. 
     Additional embodiments can additionally comprise a stop structure blocking the secondary septum from moving proximally with the needle prior to the portion of the secondary septum entering the notch. In some such embodiments, a shape of the secondary septum can change sufficiently when the portion of the secondary septum enters the notch so that the stop structure is no longer blocked by the secondary septum. 
     Yet additional embodiments can additionally comprise maintaining a distal end of the catheter tube in the patient&#39;s blood vessel while pulling the introducer needle proximally. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of a catheter assembly having features in accordance with the present disclosure; 
         FIG. 2  is an exploded, cutaway view of the catheter assembly of  FIG. 1 ; 
         FIG. 3  is a perspective view of a septum activator in accordance with one embodiment; 
         FIG. 4  is a cutaway view showing a catheter adapter with an introducer needle extending therethrough; 
         FIG. 5  is a perspective view of a secondary septum for use in the catheter adapter of  FIG. 4 ; 
         FIG. 6  shows the arrangement of  FIG. 4  as an introducer needle is being withdrawn; 
         FIG. 7  shows the arrangement of  FIG. 4  with the introducer needle further withdrawn; 
         FIG. 8A  is a schematic view of an embodiment of a secondary septum arranged in the first configuration; 
         FIG. 8B  shows the secondary septum of  FIG. 8A  and a second configuration; and 
         FIG. 9  shows a close up cutaway view of portions of another embodiment of a catheter assembly in accordance with the present disclosure. 
     
    
    
     DESCRIPTION 
     With initial reference to  FIG. 1 , an embodiment of a catheter assembly  18  is shown. The catheter assembly  18  includes a catheter adapter  20 , also sometimes referred to as a catheter hub, having a distal end  22  and a proximal end  24 . A catheter tube  30  extends from the distal end  22  of the adapter and terminates at a catheter distal end  32 . A flange or threads  34  at the proximal and  24  of the catheter adapter  20  is configured to releasably accommodate other components, such as a coupler for coupling IV fluid tubing in a luer fit or threaded arrangement. 
     As shown, an introducer needle  40  has a hollow distal tip  42 . In the illustrated embodiment, an outlet aperture  47  in the form of (or as part of) a notch  44  is formed on a side of the introducer needle  40  proximal the distal tip  42 . In the illustrated embodiment, the notch  44  is elongated and has a distal end  43  and a proximal end  45 . The notch  44  can be formed in various ways, including by crimping the needle and forming an aperture  47  at the notch in part or all of the crimped portion. The needle hub  46  is engaged with the proximal end  24  of the catheter adapter  20 . The introducer needle  40  extends from the hub  46  through the catheter adapter  20  and the catheter tube  30  so that its distal tip  42  is disposed just distal of the distal end  32  of the catheter tube  30 . 
     The illustrated needle hub  46  has a fairly simple construction. It is to be understood, however, that in additional embodiments the needle hub can be configured differently and may have additional features such as safety features including a needle tip cover, a spring-loaded needle retractor, or the like. 
     With continued reference to  FIG. 1 , a hub marker  50  is formed on the needle hub  46 , and an adapter marker  52  is formed on the catheter adapter. When the hub marker  50  and adapter marker  52  are aligned as shown in  FIG. 1 , the introducer needle  40  is aligned properly for operation in accordance with a preferred embodiment. The markers  50 ,  52  can be raised (or lowered) portions of the associated component, and/or they can be colored in order to aid visibility. In other examples, the threads or flange  34  can have a notch and the needle hub can have a projection that fits within the notch to angularly align the catheter hub to the needle hub. The notch and the projection can also be reversed. 
     With reference next to  FIGS. 2-5 , the catheter adapter  20  defines an internal lumen  56  extending from the proximal end  24  to the distal end  22 . A septum seat  58  is formed in an inner wall of the catheter adapter  20 . An elastomeric septum  60  preferably is configured to fit in the septum seat  58  so as to sealingly engage the inner wall of the catheter lumen  56  at the septum seat  58 . The illustrated septum  60  has a distal face  62  and a proximal face  64 . At least one slit  66  is formed through the septum  60  so that the septum  60  can be selectively deformed in order to open the slit and break the seal. Also, preferably the introducer needle  40  can extend through the slit  66 , but edges of the slit  66  will engage the outer walls of the needle so as to maintain a full or partial sealing engagement with the needle  40 . 
     As best shown in  FIG. 4 , a distal chamber  70  is defined within the catheter adapter lumen  56  distal of the septum  60 . A proximal chamber  72  is defined proximal of the septum  60 . 
     With continued reference to  FIGS. 2-4 , a septum activator  74  has a distal end  76  at which a distal opening  78  is formed, and a proximal end  80  at which a proximal opening  82  is formed. The illustrated septum activator  74  has a transition section  84  disposed between the distal section  86  and a proximal section  88 . A diameter of the septum activator  74  increases moving proximally through the transition section  84  so that a proximal diameter  92  of the septum activator is greater than a distal diameter  90 . An activator lumen  94  is defined within the septum activator. 
     As best shown in  FIG. 4 , when the catheter assembly is assembled, the septum activator  74  preferably is disposed within the proximal chamber  72  of the catheter adapter  20  so that the distal end  76  of the activator  74  is adjacent the proximal face  64  of the septum  60 , and the introducer needle  40  extends through the activator lumen  94 . Although not shown, the septum activator may include guides or fins along an exterior thereof for aligning to the catheter lumen to limit yawing and pitching. 
     With reference again to  FIGS. 2, 4 and 5 , an elastomeric secondary septum  100  is arranged at the distal opening  78  of the septum activator  74 . With specific reference to  FIG. 5 , the secondary septum  100  preferably comprises a distal face  102 , a proximal face  104  and a circumferential surface  106  extending between the distal and proximal faces  102 ,  104 . A needle hole  110  preferably is formed axially through the secondary septum  100 . The illustrated needle hole  110  is generally circular except for an inwardly-biased portion  112 . In the illustrated embodiment, the inwardly-biased portion  112  is generally flat when the septum  100  is at rest, and is disposed closer to an axis of the hole  110  than is the rest of the needle hole surface. A recessed portion  114  of the circumferential surface  106  is generally aligned with and radially spaced from the inwardly-biased portion  112 . 
     With continued reference to  FIG. 5 , when the introducer needle  40  (which typically has a circular cross-sectional shape) extends through the needle hole  110 , the inwardly-biased portion  112  is forced radially so as to take on a displaced shape  112   a . Similarly, when the inwardly-biased portion  112  is displaced, the recessed portion also takes on a displaced shape  114   a  so that the radius of the secondary septum  100  in the recessed portion  114  increases when the introducer needle  40  extends through the needle hole  110 . 
       FIG. 4  depicts the catheter adapter  20  with the introducer needle  40  extending therethrough so that the needle extends through the secondary septum  100  needle hole  110 , and the recessed portion  114   a  of the secondary septum  100  is radially expanded. In the illustrated embodiment, a detent or stop  120  is formed in the septum activator  74  just proximal of the secondary septum  100 . The illustrated detent  120  is an inwardly-crimped portion of the septum activator  74 , which is generally aligned with the position of the recessed portion  114 . When the recessed portion is in the expanded configuration  114   a , the detent  120  blocks the secondary septum  100  from moving proximally relative to the septum activator  74 . 
     With the catheter assembly  18  assembled as illustrated in  FIGS. 1 and 4 , the catheter assembly  18  is ready to be placed into a patient&#39;s blood vessel. In use, the clinician penetrates the patient&#39;s tissue using the distal tip  42  of the needle  40 . Once the distal tip  42  is in the blood vessel, blood will flow into the needle  40  at the tip  42  and out the aperture  47  at the notch  44  into the catheter tube  30  and/or catheter adapter  20 . More precisely, blood flashback can be expected to at least partially fill the distal chamber  42  of the catheter adapter  20 . In some embodiments, air vents may be formed through or around the septum  60  so as to relieve positive air pressure that may tend to resist blood flashback. 
     Once the catheter tube  30  is properly positioned with its distal end  32  in the patient&#39;s blood vessel, the introducer needle  40  should be removed. In a preferred embodiment, prior to such removal, the clinician ensures that the hub marker  50  and adapter marker  52  are aligned so that the introducer needle  40  is positioned with the notch  44  on the same side of the needle as the inwardly-biased portion  112  of the secondary septum  100 . As the introducer needle  40  is pulled proximally during withdrawal, the needle will slide through the needle hole  110  of the secondary septum  100 . However, since the inwardly-biased portion  112  of the needle hole  110  is in its displaced position, and the recessed portion  114   a  is correspondingly expanded, the secondary septum  100  is blocked by the detent or stop  120  from being pulled proximally by the needle  40 . 
     With reference next to  FIG. 6 , eventually the notch  44  of the introducer needle  40  is pulled through the septum  60  and into the needle hole  110  of the secondary septum  100 . As noted above, preferably the notch  44  is on the same side of the needle as the biased portion  112 . Thus, when the notch  44  passes through the needle hole  110 , the inwardly-biased portion  112  will spring into the notch  44 . In a preferred embodiment, preferably the thickness of the secondary septum  100  between the distal and proximal faces  102 ,  104  matches the length of the elongated notch  44  so that when the inwardly-biased portion  112  enters the notch  44 , it plugs the notch  44  so that blood is blocked from flowing out of the notch  44 . Also, preferably the distal face  102  and proximal face  104  of the secondary septum  100  engage the distal end  43  and proximal end  45 , respectively, of the notch  44 . 
     As the inwardly-biased portion  112  of the needle hole  110  moves into the notch  44 , the displaced recessed portion  114   a  moves towards its relaxed state, reducing the effective radius of the secondary septum  100  at the recessed portion  114  so that the recessed portion  114  either clears or can be relatively easily pulled over the detent  120 . Also, with the inwardly-biased portion  112  received into the needle notch  44 , the needle now has a firm purchase on the secondary septum  100 , as the notch distal end  43  is engaged with the distal face  102  of the septum  100 . Thus, as the needle  40  continues to be pulled proximally, the secondary septum  100  moves proximally with the needle as depicted in  FIG. 6 . 
     Preferably, the proximal opening  82  of the septum activator  74  has a diameter greater than the diameter of the secondary septum  100  so that the secondary septum can be completely removed from the catheter adapter with the needle  40  as depicted in  FIG. 7 . Further, since the secondary septum  100  effectively plugs the needle notch  44  as soon as the needle notch passes through the septum  60  and into the proximal chamber  74  of the catheter adapter  20 , the pathway of blood flow into the hollow needle tip  42  and out the needle notch  44  is plugged, and blood is blocked from flowing through the needle into the proximal chamber  72  of the catheter adapter. 
     In some embodiments, after the introducer needle  40  has been removed, a conduit coupler (not shown) that is connected to a source of IV fluids can be connected to the flange  34  of the catheter adapter  20 . During the act of coupling the conduit coupler with the flange  34  a portion of the coupler may push the septum activator  74  distally, deforming the septum  60  so that the slit  66  opens to form one or more fluid pathways through the septum  60 . IV fluids can then be delivered into the catheter adapter  20 , through the open septum  60  and into the catheter tube  30  for delivery to the patient&#39;s blood vessel. Such IV fluids may also flush blood out of the distal chamber  70 . 
     It is to be understood that other embodiments may practice the principles discussed herein while using various structures that may differ from the specifically-illustrated structures. For example, although the illustrated embodiment uses a crimped portion  120  as a detent or stop structure, other structures and configurations can also be employed, such as a ball-and-spring detent, a weak adhesive, a roughened surface, magnets in the catheter adapter body and secondary septum, or the like. Also, rather than having only a portion of the secondary septum needle hole  110  be biased inwardly, the entire needle hole can be biased inwardly so that the secondary septum will be drawn into the needle notch regardless of needle alignment. Further, the periphery of the secondary septum may or may not tend to be expanded by displacement of the needle hole engaging the needle notch. Rather, increased purchase and grip provided to the needle when the secondary septum is drawn into the needle notch may be sufficient to release the secondary septum from the particular stop structure that is employed. 
     In another embodiment, more than one aperture may be formed through the needle side so that the secondary septum is drawn into the needle at more than one position. In such an embodiment, multiple stop structures may also be employed as desired. In still other embodiments, the needle may be crimped to form one or more notches, and an opening formed at, for example, a distal end of one or each crimp. 
     With reference next to  FIGS. 8A and 8B , another embodiment of a secondary septum  200  is illustrated. This embodiment also employs a needle hole  110  with an inwardly-biased portion  112  and a circumferential surface  106  having a recessed portion  114 . Preferably, however, a generally-rigid latch insert  210  is disposed within an insert receiver  212  formed within the septum  200 . The latch insert  210  has a proximal end  214  disposed adjacent the inwardly-biased portion  112 . A distal end  216  of the latch  210  is generally aligned with the recessed portion  114  when the secondary septum  200  is in a relaxed configuration as illustrated in  FIG. 8A . In the illustrated embodiment, the insert receiver cavity  212  includes a retainer portion  218  that is shaped generally complementary to a proximal flange  220  of the latch insert  210  so that the latch insert  210  doesn&#39;t fall out of the secondary septum  200 . 
     When the introducer needle extends through the needle hole  110  so as to displace the biased portion  112   a , the latch insert  210  is pushed radially so that the distal end  216  extends radially from the recessed portion  114 . 
     With reference next to  FIG. 9 , in another embodiment, a septum activator  74  is configured with a distal mount portion  230  adjacent its distal end  76 . As shown, the secondary septum  200  can be supported at the distal mount portion  230  so that its distal face  102  is adjacent the proximal face  64  of the septum  60 . A latch receiver cavity  232  having a stop wall  234  preferably is formed in the distal mount portion  230 . The secondary septum  200  is positioned so that when the introducer needle  40  extends through the needle hole  110  the needle hole  110  is expanded, and the latch insert  210  is thus urged radially and the distal end  216  is received in the latch receiver cavity  232 . The secondary septum  200  is thus prevented by the stop wall  234  from moving proximally. However, when the introducer needle notch  44  becomes aligned with the biased portion  112 , the secondary septum  200  will return toward its relaxed position as shown in  FIG. 8A . The distal end  216  of the latch insert  210  will thus be withdrawn from the latch receiver cavity  232  so that the secondary septum  200  will no longer be blocked from moving proximally relative to the activator  74 . 
     With continued reference to  FIG. 9 , in the illustrated embodiment, an inner diameter of the activator  74  increases immediately proximal to the distal mount portion  230 . The increased diameter provides increased space to minimize interference of the activator  74  with the secondary septum as it is drawn proximally. 
     Although inventive subject matter has been disclosed in the context of certain preferred or illustrated embodiments and examples, it will be understood by those skilled in the art that the inventive subject matter extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In addition, while a number of variations of the disclosed embodiments have been shown and described in detail, other modifications, which are within the scope of the inventive subject matter, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or subcombinations of the specific features and aspects of the disclosed embodiments may be made and still fall within the scope of the inventive subject matter. For example, it is contemplated that additional embodiments can combine structure and principles suggested by, for instance, both  FIGS. 4 and 9 . Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed inventive subject matter. Thus, it is intended that the scope of the inventive subject matter herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims that follow.