certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure , function , manufacture , and use of the devices and methods disclosed herein . one or more examples of these embodiments are illustrated in the accompanying drawings . those skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non - limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims . the features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments . such modifications and variations are intended to be included within the scope of the present invention . a person skilled in the art will appreciate that , while methods and devices are described herein in connection with catheters implantable in humans , the methods and devices can also be used in any instance in which a seal is desired around an elongate device implanted into or otherwise extending from a plant , an animal , and / or any non - living machine , structure , or system or in which a flushing capability is desired . in addition , while the methods and devices disclosed herein are described primarily with respect to intravenous catheters , they can also be used with any of a variety of other devices and other procedures including , without limitation , arterial monitoring lines , access sheaths for intravascular procedures such as angiography and stenting , access sheaths for intravascular therapeutic devices such as intra - aortic balloon pumps and ventricular support devices , etc . further details on catheter - dressing systems can be found in u . s . publication no . 2012 / 0197204 , filed on jan . 13 , 2012 and entitled “ snap - seal sterile intravascular catheter - dressing system ,” the entire contents of which are incorporated herein by reference . further details on catheter - dressing systems can also be found in u . s . publication no . 2011 / 0106014 , filed on oct . 28 , 2010 and entitled “ sealed sterile catheter dressings ,” the entire contents of which are incorporated herein by reference . fig1 a shows a side view of a catheter flushing or injection system 10 that includes a needle containment device 12 . the needle containment device 12 can be attached to a catheter assembly 14 . the system 10 can also include a dressing , as described in further detail below . the needle containment device 12 can contain a volume of injectable agent . while saline is generally referred to herein , it will be appreciated that the injectable agent can be or can include any of a variety of fluids , solutions , etc ., including without limitation therapeutic agents , blood , blood substitutes , nourishing agents , flush solutions , and so forth . in addition , as used herein , the terms “ sterile saline ” and “ saline ” refer not only to pure saline , but also to solutions that include saline and one or more other components , such as anticoagulants ( e . g ., heparin ). in the illustrated embodiment , a full sterile saline bag 16 is contained in the “ top ” half of a chamber internal to the needle containment device 20 . a roller pin 18 attached to an upper sliding collar 20 can be configured to compress the bag 16 as the upper sliding collar 20 is advanced distally , thereby flushing the contained saline into the catheter assembly 14 . the system 10 can also include an insertion needle 22 that can be attached to a lower sliding collar 24 of the needle containment device 12 . in fig1 a , the needle 22 ( and the attached collar 24 ) are shown in a deployed position in which the needle 22 is inserted through the catheter assembly 14 with a tip of the needle extending beyond the distal catheter end ( e . g ., for insertion purposes ). a saline injection hole / channel 26 can be closed when the needle 22 is in this deployed position ( as will be seen , when the needle 22 is withdrawn into the needle containment device 12 , the hole / channel 26 can be exposed , which then allows injection of the contained saline into the catheter assembly 14 , e . g ., for the purpose of flushing the catheter assembly of blood ). it should be noted that other saline containment and injection actuators can be used , including a vertically collapsible “ accordion ” actuator or a central plunger actuator ( as described below and shown in fig6 a - 6f ). in an “ accordion ” type compression actuator , the saline or other injectable agent can be contained in a soft expanded accordion container , and compression of this expanded accordion chamber ( filled with saline in its expanded form ) can compress the chamber and empty the saline . this accordion chamber can be contained inside the needle containment device 12 with a compression actuator connected to the upper sliding collar 20 , or one side of the needle containment device 12 can be occupied by this mounted but exposed accordion chamber . preferably , the maximum outer diameter of the saline - containing needle containment device 12 is less than or equal to the diameter of the catheter hub mounting point 28 . this can allow a dressing to be slid over the needle containment device 12 so that it can be mounted at the specified catheter hub mating point 28 . in some embodiments , the dressing can form a circumferential seal around a specific mating point on the catheter hub . in other embodiments , the dressing can form a circumferential seal around other portions of a catheter assembly , such as a catheter hub cap or the implanted catheter itself . fig1 b is a side view that shows the needle 22 retracted into the needle containment device 12 ( via the lower sliding collar 24 ), and the saline flush injected into the catheter ( via compression of the contained saline bag by the upper collar 20 and its attached “ rolling pin ” 18 ). fig1 c is a side view of the needle assembly and related central channel structures which can allow for opening of a saline injection hole / channel when the needle is withdrawn . as shown in the top part of fig1 c , the hole / channel 26 can be open when the needle 22 is in the retracted position . as shown in the bottom part of fig1 c , the hole / channel 26 can be closed ( e . g ., obstructed by the needle 22 or a structure coupled thereto ) when the needle 22 is in the deployed position . fig1 d is a top view of the needle assembly and related central channel structures which can allow for opening of a saline injection hole / channel when the needle 22 is withdrawn . fig1 e is an exploded side view of the needle assembly and related central channel components . the needle 22 can include a t - shaped proximal end which can be operably attached to the lower collar 24 shown in fig1 a and 1b , such that sliding of the collar 24 along the exterior of the needle containment device 12 effects corresponding longitudinal translation of the needle 12 . a hole - containing component 30 can be attached to or formed integrally with the needle containment device 12 body . the inner channel of the catheter assembly 14 is shown on the right . fig1 f is an exploded top view of the needle assembly and related central channel components . fig1 g is a top view of the needle containment device 12 with the needle 22 deployed and the saline chamber 16 still full . fig1 h is a top view of the needle containment device 12 with the needle 22 retracted , after injection / flushing of the saline into the catheter assembly 14 . fig1 i shows the needle containment device 12 detached from the inserted and flushed catheter , for example after the needle containment device has been used as a handle for mounting of a circumferential sealing dressing ( e . g ., a dressing as disclosed in the references incorporated above ). in one embodiment , some or all of the following steps can be executed in connection with the system 10 illustrated in fig1 a - 1i . first , the catheter body of the catheter assembly 14 can be inserted into a patient . second , the insertion needle 22 can be withdrawn from the catheter and into the needle containment device 12 by sliding the lower collar 24 proximally . third , saline flush can be injected from the needle containment device 12 into the inserted catheter by sliding the upper collar 20 distally . fourth , a sterile circumferentially - sealing dressing 30 can be slid / mounted over the needle containment device 12 and into final sealing / securing position over the inserted catheter . fifth , an adhesive backing 32 can be removed from the dressing and the dressing can be circumferentially sealed around the catheter insertion site . sixth , the needle containment device can be disconnected / removed from the catheter - dressing complex . fig2 a is a side view of the system 10 of fig1 a - 1i after insertion of the catheter into a blood vessel . fig2 b is a side view that shows the insertion needle 22 having been withdrawn into the saline flush needle containment device 12 . this can be achieved by sliding the lower hemi - cylindrical collar 24 back ( i . e ., proximally away from the distal skin insertion site ). the collar 24 and / or the needle 22 can be configured to lock into place when withdrawn to a fully retracted position or any of a variety of positions intermediate to the fully retracted position and the fully deployed position . fig2 c is a side view that shows the saline flush contained in the flush compartment of the needle containment device 12 having been injected into the catheter 14 . this can be achieved by sliding the upper hemi - cylindrical collar 20 forward ( i . e ., distally towards the distal skin insertion site ), thereby compressing the saline container 16 and forcing the saline through the opening 26 in the central shaft , which opening 26 can be exposed by withdrawal of the needle 22 . fig2 d shows an exemplary integrated mating dressing 30 being mounted over the sterile handle provided by the needle containment device 12 . fig2 e shows the dressing 30 slid into position and mated with specific mating features of the catheter hub . an adhesive backing portion 32 of the dressing 30 can be peeled away at this time to adhere the dressing to the skin surface and thereby form a circumferential seal around the catheter and the catheter insertion site . the mating interaction between the dressing and catheter can also serve to fully secure the catheter to the patient , preventing both longitudinal and rotational movement . fig2 f shows the needle containment device 12 detached from the catheter - dressing complex . the needle containment device 12 , which now safely contains the insertion needle 22 and is devoid of saline , can now be ready for safe disposal . fig3 a is a side view of a saline flush handle 34 configured to mate with a standard luer lock ® type connection device . the handle 34 is shown as it might look after removal from its sterile packaging . a plunger 36 is shown in a withdrawn position , ready to inject once a luer lock ® connector 38 is connected to a catheter hub after successful catheter insertion . sterile saline or other injectable agents can be contained in a chamber 40 in the handle 34 . slits 42 in a portion of the handle “ skirt ” that fits over the luer lock ® connector 38 can enable the skirt to shrink in diameter as a dressing 30 is slid over the handle 34 to mount onto the neck of the luer lock ® connector 38 ( as depicted in fig4 d , below ). preferably , the maximum outer diameter of the saline flush handle 34 is less than or equal to the diameter of the specified hub cap mounting point . this can allow the dressing 30 to be slid over the handle 34 so that it can be mounted at the specified catheter hub cap mating point . the proximal “ plunger handle ” end 44 of the saline flush handle 34 can be uniquely tapered to allow easy mounting of the dressing 30 onto the handle 34 . in particular , the proximal end 44 of the handle 34 can have a first diameter that gradually tapers distally into a second diameter that is greater than the first diameter . as noted above , the first and second diameters , and the maximum outer diameter of the handle 34 , can all preferably be less than or equal to the outer diameter of a dressing mating point on the catheter , catheter hub , or catheter hub cap . fig3 b is a side view of the saline flush handle 34 with the plunger 36 in the injected position ( after injecting the sterile saline or other injectable agent into the luer lock ® connector 38 and catheter , for example to flush through blood that would otherwise cause clotting and clogging of the newly inserted catheter ). fig3 c is a side view of the saline flush handle disconnected from the luer lock ® connector 38 . disconnection of the handle can be performed , for example , after a sterile dressing 30 has been mounted to the luer lock ®- catheter complex as shown in fig4 f . fig3 d is a side view of a saline flush handle 46 configured to mate with a clave ® needleless connection device . the handle 46 is shown as it might look after removal from its sterile packaging . the plunger 48 is shown in a withdrawn position , ready to inject once a clave ® connector 50 is connected to a catheter hub after successful catheter insertion . sterile saline or other injectable agents can be contained in a chamber 53 in the handle . like the embodiment shown in fig3 a , the saline flush handle 46 of fig3 d can include a uniquely tapered proximal end 52 to allow easy mounting of the dressing 30 onto the handle 46 . in particular , the proximal end 52 of the handle 46 can have a first diameter that gradually tapers distally into a second diameter that is greater than the first diameter . the first and second diameters , and the maximum outer diameter of the handle 46 , can all preferably be less than or equal to the outer diameter of a dressing mating point on the catheter , catheter hub , or catheter hub cap . fig3 e is a side view of the saline flush handle 46 with the plunger 48 in the injected position ( after injecting the sterile saline or other injectable agent into the clave ® connector 50 and catheter , for example to flush through blood that would otherwise cause clotting and clogging of the newly inserted catheter ). fig3 f is a side view of the saline flush handle disconnected from the clave ® connector 50 . disconnection of the handle can be performed , for example , after the sterile dressing has been mounted to the clave ®- catheter complex as shown in fig5 f . while saline flush handles are disclosed that are specifically configured to couple using luer lock ® or clave ® type connectors , it will be appreciated that the saline flush handles can be readily adapted to other standard or non - standard connectors . in one embodiment , some or all of the following steps can be executed in connection with the system illustrated in fig3 a - 3c . first , the saline flush handle 34 and luer lock ® connector 38 complex can be mounted to an inserted catheter assembly 14 . second , the catheter can be flushed with sterile saline . third , a circumferentially - sealing sterile dressing 30 can be placed over the handle and the inserted catheter . fourth , the saline flush handle can be removed from the inserted catheter . fig4 a is a side view of the sterile saline flush handle 34 and attached luer lock ® connector 38 , which can be connected to an inserted “ standard vascular ” catheter 14 or any of a variety of other catheters having a corresponding luer lock ® connector . fig4 b is a side view showing the sterile saline flush handle 34 attached to the catheter 14 . fig4 c is a side view of the sterile saline flush handle 34 after the saline has been injected into the catheter , and as a circumferential sealing dressing 30 is first being mounted over the handle . the tapered proximal tip 36 of the handle can facilitate sliding of the dressing 30 onto the handle 34 . fig4 d is a side view of the sterile saline flush handle 34 and luer lock ®- catheter complex after the dressing 30 has been slid down into final mounting sealing position , but before the adhesive backing 32 has been peeled away ( for final adhesion of the dressing to the skin ). it will be appreciated that the dressing can be configured to form a seal at a particular mating site on the luer lock ® catheter hub cap . the dressing can also be configured to form a seal with other components of the catheter assembly , such as a catheter hub or the implanted catheter itself . fig4 e is a side view of the sterile saline flush handle 34 and luer lock ®- catheter complex after the dressing 30 has been adhered to the skin in final mounting securing position . fig4 f is a side view showing detachment of the sterile saline flush handle 34 from the mounted and secured luer lock ®- catheter - dressing complex . any of a variety of structures or techniques can be used to detachably couple the handle 34 to the luer lock ® hub cap , such as a threaded interface , a friction fit , a frangible portion , and so forth . in one embodiment , some or all of the following steps can be executed in connection with the system illustrated in fig3 d - 3f . first , the saline flush handle 46 and clave ® connector 50 complex can be mounted to an inserted catheter assembly 14 . second , the catheter can be flushed with sterile saline . third , a circumferentially - sealing sterile dressing 30 can be placed over the handle and the inserted catheter . fourth , the saline flush handle 46 can be removed from the inserted catheter . fig5 a is a side view of the sterile saline flush handle 46 and attached clave ® connector 50 , which can be connected to an inserted “ standard vascular ” catheter 14 or any of a variety of other catheters having a corresponding clave ® connector . fig5 b is a side view showing the sterile saline flush handle 46 and clave ® connector 50 attached to the catheter 14 . fig5 c is a side view of the sterile saline flush handle 46 after the saline has been injected into the catheter , and as a circumferential sealing dressing 30 is first being mounted over the handle . the tapered proximal tip 52 of the handle can facilitate sliding of the dressing 30 onto the handle 46 . fig5 d is a side view of the sterile saline flush handle 46 and clave ®- catheter complex after the dressing 30 has been slid down into final mounting sealing position , but before the adhesive backing 32 has been peeled away ( for final adhesion of the dressing to the skin ). it will be appreciated that the dressing can be configured to form a seal at a particular mating site on the clave ® catheter hub cap . the dressing can also be configured to form a seal with other components of the catheter assembly , such as a catheter hub or the implanted catheter itself . fig5 e is a side view of the sterile saline flush handle 46 and clave ®- catheter complex after the dressing 30 has been adhered to the skin in final mounting securing position . fig5 f is a side view showing detachment of the sterile saline flush handle 46 from the mounted and secured clave ®- catheter - dressing complex . any of a variety of structures or techniques can be used to detachably couple the handle 46 to the clave ® hub cap , such as a threaded interface , a friction fit , a frangible portion , and so forth . fig6 a shows a side view of another embodiment of a catheter flushing or injection system that includes a needle containment device 54 . the needle containment device 54 can include a central plunger actuator assembly 56 and can be attached to a catheter 14 . the system can also include a dressing , as described above . the system is shown as it would appear just after its removal from its sterile packaging and in an insertion - ready state . the plunger assembly 56 can include a handle portion 66 and two or more elongate feet 62 which can be configured to spread apart from one another . the plunger assembly 56 can be disposed within a central channel 68 formed in the needle containment device 54 . the needle containment device 54 can also include a fluid chamber 70 disposed around the central channel 68 that can contain any of a variety of injectable agents , such as sterile saline . a plunger ring 64 can be slidably disposed about the central channel 68 , and can define the proximal wall of the fluid chamber 70 such that the fluid chamber 70 has a variable volume based on the position of the plunger ring 64 . the needle containment device 54 and / or the plunger handle 66 can include a uniquely tapered proximal end to allow easy mounting of a dressing 30 onto the needle containment device 54 . in particular , the proximal end 76 of the needle containment device 54 and the plunger handle 66 can each have a first diameter that gradually tapers distally into a second diameter that is greater than the first diameter . the first and second diameters of each component , and the maximum outer diameter of the needle containment device 54 , can all preferably be less than or equal to the outer diameter of a dressing mating point on the catheter , catheter hub , or catheter hub cap . fig6 b shows the system of fig6 a with the plunger assembly 56 partially withdrawn proximally to retract an insertion needle 22 coupled thereto into the needle containment device 54 . the distal ends of the elongate feet 62 can be attached to the needle 22 using any of a variety of techniques , such as a friction fit , interference fit , snap fit , etc . fig6 c shows the system of fig6 a with the plunger assembly 56 fully withdrawn proximally such that the insertion needle 22 is fully contained within the needle containment device 54 . the system can be configured to lock the needle in a retracted position for safe disposal . for example , when the needle 22 is fully retracted , one or more spring detents 72 formed on a head 60 of the needle 22 can expand radially outwards to engage a proximal locking surface 74 , thereby preventing subsequent proximal movement of the needle 22 . alternatively , or in addition , radial retraction of the inner channel wall after the insertion needle head has been withdrawn past it can serve to lock the needle into the withdrawn position . as also shown in fig6 c , a hole 58 can be provided in the sidewall of the central channel 68 of the needle containment device 54 . the hole 58 can be exposed by full withdrawal of the needle 22 , and can provide an aperture through which saline or other injectable agents stored in the fluid chamber 70 can be transferred into the central channel 68 and the attached catheter assembly 14 . fig6 d shows the system with the plunger assembly 56 disengaged from the head 60 of the needle 22 . in particular , the feet 62 of the plunger assembly 56 can be configured to disengage from the head 60 of the needle 22 when a distal force is applied to the plunger assembly 56 while the needle 22 is locked in the retracted position . fig6 d shows the feet 62 of the plunger assembly 56 just beginning to split around the locked needle head 60 , so that the spread feet 62 begin to push down onto the plunger ring 64 in the sterile saline chamber . the proximal end of the needle head 60 locking point ( e . g ., the spring detents 72 ) can have a conical shape to allow this splitting of the plunger feet 62 to naturally occur as the plunger assembly 56 is pushed distally . fig6 e shows the system with the plunger assembly 56 and plunger ring 64 further advanced into the needle containment device 54 ( roughly ⅓ of the saline having been injected into the catheter 14 through the hole 58 in the central channel exposed by the withdrawal of the needle 22 ). fig6 f shows the assembly with the saline flush fully injected . at this time , any of the methods described above can be used to mount a sterile sealing dressing 30 over the needle containment device 54 and into a final mating position on the catheter assembly 14 , and to detach the needle containment device 54 from the catheter hub or hub cap . fig7 a shows an enlarged view of the system of fig1 a - 1i . fig7 b shows an enlarged view of the system of fig3 a - 3c . fig7 c shows an enlarged view of the system of fig3 d - 3f . fig7 d shows an enlarged view of the system of fig6 a - 6f . any of the components of the devices disclosed herein can be transparent or semi - transparent to allow visualization of blood , saline , or other materials contained therein . any of the needle containment devices disclosed herein can include a lockout feature to lock the needle in the retracted position to facilitate safe removal and disposed . the interior or exterior of any of the components of the devices disclosed herein can be coated and / or impregnated with a sterilizing agent . the systems described herein can also be packaged in the form of a kit including dressings , catheters , hubs , hub caps , hub protection devices , insertion needles , needle containment devices , and / or other components of various sizes and shapes for use with various sized catheters , patients , body parts , etc . the kit can also include various items for sterile site preparation and sterile catheter insertion , such as tourniquets , preparation solutions , solution applicators , sterile saline flush , and / or sterile gloves . the devices disclosed herein can be designed to be disposed of after a single use , or they can be designed to be used multiple times . in either case , however , the device can be reconditioned for reuse after at least one use . reconditioning can include any combination of the steps of disassembly of the device , followed by cleaning or replacement of particular pieces , and subsequent reassembly . in particular , the device can be disassembled , and any number of the particular pieces or parts of the device can be selectively replaced or removed in any combination . upon cleaning and / or replacement of particular parts , the device can be reassembled for subsequent use either at a reconditioning facility , or by a caregiver immediately prior to a catheterization procedure . those skilled in the art will appreciate that reconditioning of a device can utilize a variety of techniques for disassembly , cleaning / replacement , and reassembly . use of such techniques , and the resulting reconditioned device , are all within the scope of the present application . preferably , the invention described herein will be processed before use . first , a new or used device is obtained and if necessary cleaned . the device can then be sterilized . in one sterilization technique , the instrument is placed in a closed and sealed container , such as a plastic or tyvek bag . the container and device are then placed in a field of radiation that can penetrate the container , such as gamma radiation , x - rays , or high - energy electrons . the radiation kills bacteria on the device and in the container . the sterilized device can then be stored in the sterile container . the sealed container keeps the device sterile until it is opened in the medical field . it is preferred that the device is sterilized . this can be done by any number of ways known to those skilled in the art including beta or gamma radiation , ethylene oxide , steam , and / or a liquid bath ( e . g ., cold soak ). one skilled in the art will appreciate further features and advantages of the invention based on the above - described embodiments . accordingly , the invention is not to be limited by what has been particularly shown and described , except as indicated by the appended claims . all publications and references cited herein are expressly incorporated herein by reference in their entirety .
methods and devices are disclosed herein that generally involve a sterile catheter - dressing system that allows for integrated injection of fluids , e . g ., a saline flush , during the process of catheter insertion and sterile dressing placement . such methods and devices can be used as a fully integrated catheter insertion system , or to convert existing catheter insertion devices and methods into integrated flush and sterile sealing catheter - dressing systems . such methods and devices can greatly simplify the catheter insertion process , and can allow the reproducible placement of a fully sterile and flushed vascular catheter , as well as the placement of a durably sterile circumferentially sealing and securing dressing .