Patent Publication Number: US-2022233836-A1

Title: Syringe With Disinfecting Feature

Description:
TECHNICAL FIELD 
     The present disclosure relates to syringe assemblies, and particularly to syringe assemblies comprising a disinfecting cap for use in flush procedures for vascular access devices (VAD&#39;s). 
     BACKGROUND 
     VAD&#39;s are commonly used therapeutic devices and include intravenous (IV) catheters. There are two general classifications of VAD&#39;s, peripheral catheters and central venous catheters. To ensure VAD&#39;s are used and maintained correctly, standards of practice have been developed, which include a cleaning procedure, commonly referred to as flushing a catheter. 
     VAD standards of practice usually recommend that flush procedures be performed after catheter placement, before fluid infusion, and before and after drug administration, blood sampling, transfusions and parenteral nutrition. The goal of these flush procedures is to confirm catheter patency, avoid drug incompatibilities, ensure complete drug dose administration, prevent thrombus formation and minimize the risk of blood stream infections. Flush procedures require different types and amounts of flush solutions. The most commonly used flush solutions are saline and/or heparin lock solution. The type of flush solution and amount vary depending on the specific type of catheter. Flush solution volumes between 5 and 10 ml are most common but can range from 1 ml to 20 ml. 
     For flush procedures, an IV line refers to a system that can include a VAD, a tubing set with clamp and a VAD connector as a termination. Common types of VAD connectors are covered by pierceable septums or pre-slit septums made of rubber or another elastomeric material, which permits insertion of a sharp needle cannula in order to infuse fluids into or to withdraw fluids from the catheter. Upon withdrawal of the needle cannula, the septum seals itself. Ports having pre-slit septums are used with blunt plastic cannula or the frusto-conically shaped tip of a syringe barrel. The syringe tip or the blunt plastic cannula (which is usually attached to a syringe) is gently pushed through the pre-slit septum to establish fluid communication. 
     IV valves, which are another type of VAD connector that do not require a needle having a sharp tip, are activated by the frusto-conically shaped tip of a syringe barrel to allow fluid communication between the interior of the syringe and the catheter. These valves may contain features for delivering fluid from a storage compartment in the valve to the catheter, and are referred to in the art as positive displacement valves. An example of such a valve is disclosed in U.S. Pat. No. 6,206,861. 
     Bacteria and other microorganisms may gain entry into a patient&#39;s vascular system from access hubs and ports/valves upon connection to the VAD to deliver the fluid or pharmaceutical. Each access hub (or port/valve or connection) is associated with some risk of transmitting a catheter related bloodstream infection (CRBSI), which can be costly and potentially lethal. Contamination can occur during drug mixing, attachment of a cannula, and insertion into the access hub. Presently, the risk to hospitals and patients is a substantial function of the diligence of the clinician performing the connection, and this diligence is largely uncontrollable. 
     A product currently available that aims to combat the problems associated with contaminated VAD connectors is the SwabCap®. This device disinfects a VAD connector by covering the connector and protecting it from touch and airborne contamination after the cap has been applied. As the SwabCap® is twisted onto a VAD connector, a foam pad inside the cap is compressed, releasing the isopropyl alcohol that passively disinfects the top and threads of the VAD connector while the cap is in place. Because the SwabCap® is a separate component, room for error exists so the cap may not be utilized after every step of the flush process. Thus, the cap does not ensure compliance with aseptic technique. 
     There is a need, therefore, for a flush syringe assembly that promotes compliance with aseptic technique by eliminating the additional swabbing and disinfecting steps. 
     SUMMARY 
     Aspects of the present disclosure are directed to a syringe assembly for use in flush applications and methods of disinfecting syringes. Syringe assemblies, for example, a flush syringe assembly according to a first aspect of the present disclosure comprise a barrel including a side wall having an outside surface, an inside surface defining a chamber for retaining fluid, an open proximal end, and a distal end including a distal wall with a distal tip extending distally therefrom having a first passageway therethrough in fluid communication with said chamber; a removable seal disposed on the peripheral distal surface; and a cap and an absorbent pad containing disinfectant disposed between the removable seal and the distal tip, the cap rotatable from a first position in which the distal tip is covered by the cap and a second position in which the distal tip of the barrel is exposed through the open distal end of the outer sleeve. In some embodiments, the assembly further comprises an outer sleeve slidably engaged with the outside surface of the barrel, the outer sleeve comprising an inner surface, an outer surface, and an open distal end comprising a peripheral distal surface, wherein relative sliding movement of the outer sleeve and the barrel to move distal tip of the barrel and the distal end of the outer sleeve closer together causes the distal tip to rotate the cap from the first position to the second position. 
     In as a second embodiment, a syringe assembly, for example, a flush syringe assembly comprises a barrel including a side wall having an outside surface, an inside surface defining a chamber for retaining fluid, an open proximal end, and a distal end including a distal wall with a distal tip extending distally therefrom having a first passageway therethrough in fluid communication with said chamber; and a cap covering the distal tip, the cap comprising a proximal side that covers the distal dip and a distal side including an absorbent pad mounted thereon, the cap pivotally movable from a first position in which the cap covers the distal tip to a second position in which the cap is moved away from the distal tip 
     A second aspect of the present disclosure pertains to method of disinfecting a vascular access device. The method according to one embodiment comprises exposing an absorbent pad containing disinfectant at a distal end of a flush syringe assembly comprising a barrel having a distal tip covered by a cap, contacting the vascular access device with absorbent pad, and rotating the cap to expose the distal tip of the barrel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a flush syringe assembly according to an embodiment of the present disclosure; 
         FIG. 2  is perspective view of a flush syringe assembly according to an embodiment of the present disclosure; 
         FIG. 3  is an enlarged partially cross-sectioned side elevation view of the flush syringe assembly of  FIG. 2 ; 
         FIG. 4  if a partial perspective view showing the distal portion of the flush syringe assembly of  FIG. 2 ; 
         FIG. 5  is a perspective view of the flush syringe of  FIG. 2  with the cap extended from the distal end of the flush syringe; 
         FIG. 6  is an enlarged partially cross-sectioned side elevation of the flush syringe of  FIG. 2  with the cap extended from the distal end of the flush syringe; 
         FIG. 7  is a partial perspective view of the flush syringe of  FIG. 2  with the cap extended from the distal end of the flush syringe; 
         FIG. 8A  is a perspective view of the distal side the cap of the flush syringe of  FIG. 2 ; 
         FIG. 8B  perspective view the proximal side the cap of the flush syringe of  FIG. 2 ; 
         FIG. 9  is a perspective view of the alignment collar of the flush syringe of  FIG. 2 ; 
         FIG. 10  is an exploded perspective view of a flush syringe assembly according to a second embodiment of the present disclosure; 
         FIG. 11  is perspective view of a flush syringe assembly according to the second embodiment of the present disclosure; 
         FIG. 12  is an enlarged partially cross-sectioned side elevation of the flush syringe assembly of  FIG. 11  with the cap in the retracted position; 
         FIG. 13  is an enlarged partially cross-sectioned side elevation of the flush syringe assembly of  FIG. 11  with the cap shown moving from a retracted to an extended position; 
         FIG. 14  is an enlarged partially cross-sectioned side elevation of the flush syringe assembly of  FIG. 11  with the cap in the extended position from the distal end of the flush syringe; 
         FIG. 15  is a partial perspective view of the distal end of the flush syringe assembly with the cap in the extended position 
         FIG. 16A  is a perspective view of the distal side the cap of the flush syringe assembly of  FIG. 11 ; 
         FIG. 16B  is a perspective view of the proximal side of the cap of the flush syringe assembly of  FIG. 11 ; and 
         FIG. 17  is a perspective view of the alignment collar of the flush syringe assembly of  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION 
     Before describing several exemplary embodiments of the disclosure, it is to be understood that the disclosure is not limited to the details of construction or process steps set forth in the following description. The disclosure is capable of other embodiments and of being practiced or being carried out in various ways. 
     With respect to terms used in this disclosure, the following definitions are provided. 
     Reference to “flush syringe assembly” includes syringes that are indicated for use in the flushing of VADs. The practice of flushing ensures and maintains catheter patency and helps prevent the mixing of incompatible pharmaceuticals. 
     As used herein, the use of “a,” “an,” and “the” includes the singular and plural. As used herein, the term “catheter related bloodstream infection” or “CRBSI” refers to any infection which results from the presence of a catheter or IV line. As used herein, the term “microorganism” refers to a microbe or organism that is unicellular or lives in a colony of cellular organisms. Microorganisms are very diverse; they include, but are not limited to bacteria, fungi, archaea, and protozoans. Microorganisms are often the cause of CRBSIs. The most common microorganisms associated with CRBSIs include, but are not limited to,  Staphylococcus aureus  and epidermis,  Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa , and  Candida albicans.    
     As used herein, the terms “antimicrobial agent” or “antimicrobial” refers to substances that kill or inhibit the growth of microorganisms such as bacteria, fungi, archaea, or protozoans. Antimicrobial agents either kill microbes, or prevent the growth of microbes. As used herein, the term “disinfectant” refers to antimicrobial substances that are used on non-living objects or outside the body, e.g., on the skin. In one or more embodiments, disinfectants or antimicrobial agent include, but are not limited to, ethanol, 2-propanol, butanol, methylparaben, ethylparaben, propylparaben, propyl gallate, butylated hydroxyanisole (BHA), butylated hydroxytoluene, t-butyl-hydroquinone, chloroxylenol, chlorohexidine, dichlorobenzyl alcohol, dehydroacetic acid, hexetidine, triclosan, hydrogen peroxide, colloidal silver, and mixtures thereof. 
     As used herein, the terms “absorbent material” and “absorbent pad” refer to a material having capacity or tendency to absorb or soak up another substance. In one or more embodiments, the absorbent material or absorbent pad has a tendency to absorb a disinfectant or antimicrobial. Absorbent materials and absorbent pads may include sponges, absorbent cottons, foam, other absorbent fabrics, and synthetic polymer matrices. 
     As used herein, the term “Luer connector” refers to a connection collar that is the standard way of attaching syringes, catheters, hubbed needles, IV tubes, etc. to each other. The Luer connector consists of male and female interlocking tubes, slightly tapered to hold together better with even just a simple pressure/twist fit. Luer connectors can optionally include an additional outer rim of threading, allowing them to be more secure. The Luer connector male end is generally associated with a flush syringe and can interlock and connect to the female end located on the VAD. A Luer connector comprises a distal end, a proximal end, an irregularly shaped outer wall, a profiled center passageway for fluid communication from the chamber of the barrel of a syringe to the hub of a VAD. A Luer connector also has a distal end channel that releasably attaches the Luer connector to the hub of a VAD, and a proximal end channel that releasably attaches the Luer connector to the barrel of a syringe. 
     According to one or more embodiments, a syringe assembly is provided that includes an absorbent material or an absorbent pad containing disinfectant or antimicrobial material that is moved away from the distal end of the syringe to expose the syringe distal tip. In one or more embodiments, the absorbent material is positioned such that there are minimal obstructions to the syringe distal tip, which allows the syringe distal tip to access ports that are typically difficult to access, such as Y-connectors. According to one or more embodiments, device activation so that the disinfectant is exposed is achieved by squeezing two parts of the syringe assembly together. This allows a user of the assembly to activate the device with one hand, which prevents interruption of workflow. 
     Referring now to  FIGS. 1-9 , a first embodiment of a flush syringe assembly  100  is shown. The flush syringe assembly  100  comprises a barrel  102  including a side wall  104  having an outside surface  106 , an inside surface  108  defining a chamber  110  for retaining fluid. The barrel  102  further comprises an open proximal end  112 , and a distal end  114  including a distal wall  116  with a distal tip  118  extending distally therefrom having a first passageway  120  therethrough in fluid communication with the chamber  110 . 
     The embodiment shown in  FIGS. 1-11  further comprises an outer sleeve  132  slidably engaged with the outside surface  106  of the barrel  102 , the outer sleeve  132  comprising an inner surface  134 , an outer surface  136 , and an open distal end  138  comprising a peripheral distal surface  140 . The syringe assembly  100  further comprises a removable seal  150  disposed on the peripheral distal surface  140 . The apparatus further comprises a cap  152  and an absorbent pad  154  containing disinfectant disposed between the removable seal  150  and the distal tip, the cap  152  rotatable from a first position in which the distal tip  118  of the barrel  102  is covered by the cap  152  and a second position in which the distal tip  118  of the barrel  102  is exposed through the open distal end  138  of the outer sleeve  132 . 
       FIGS. 2-4  show the flush syringe assembly  100  in the first position, with the distal tip  118  of the barrel  102  covered by the cap  152 . In this embodiment, the cap  152  comprises a proximal side  151  and a distal side  153 . In the first position, the proximal side  151  of the cap  152  covers the distal tip  118  of the barrel  102 . In the embodiment shown in  FIGS. 1-9 , the cap  152  comprises a recess  156  on the proximal side  151  of the cap for receiving the distal tip  118  of the barrel when the cap  152  is in the first position, which is a folded down or covered position. Furthermore, in the embodiments shown in  FIGS. 1-9 , the absorbent pad  154  is located on the distal side  153  of the cap  152 . In the embodiment shown, the distal side  153  of the cap  152  comprises a housing  158  which receives the absorbent pad  154 . 
     Thus, in the embodiments shown in  FIGS. 1-9 , the syringe assembly comprising the barrel  102  includes the cap  152  covering the distal tip  118  of the barrel  102 , with the cap  152  including a proximal side  151  that covers the distal tip  118  and a distal side  153  including the absorbent pad  154  mounted thereon. The cap  152  is pivotally movable from a first position in which the cap  152  covers the distal tip  118  to a second position in which the cap  152  is moved away from the distal tip  118 . In some embodiments, the cap  152  is rotatably disposed between the distal tip  118  and the open distal end  138  of the outer sleeve. 
     Referring now to  FIGS. 5-7 , relative sliding movement of the outer sleeve  132  and the barrel  102  moves the distal tip  118  of the barrel  102  and the open distal end  138  of the outer sleeve  132  closer together, which pushes the distal tip  118 , causing the distal tip to rotate the cap  152  from the first position to the second position.  FIG. 5  shows the cap  152  rotated in the direction of arrow  165  from the first position  152   a  in which the cap  152  covers the distal tip  118 , to position  152   b  as the cap  152  is rotated off of the distal tip to position  152   c  and then position  152   d  where the cap  152  is in the uncovered position and the distal tip  118  is exposed as shown in  FIG. 7 . The relative sliding movement of the outer sleeve  132  and the barrel occurs when a user of the syringe assembly applies proximally directed force (in the direction of arrow  141  in  FIG. 2 ) to the outer sleeve flange  139  while applying distally directed force (in the direction of arrow  121  in  FIG. 2 ) to the barrel flange  119 . According to one or more embodiments, a user can clean a VAD with the syringe assembly  100  and then connect the syringe assembly to the VAD using one hand. For example, a user can hold the syringe assembly with cap in the first position as shown in  FIGS. 2-4  by gripping placing the outer sleeve between the index finger and middle finger of their hand. The user can then move the cap  152  and absorbent pad  154  out of the way by gripping the outer sleeve  132 , applying the proximally directed force to the outer sleeve flange  139  by placing the outer sleeve between the user&#39;s fingers and pressing the barrel flange  119  into the palm of the user&#39;s hand or thumb as desired, which applies the distally directed force to the barrel flange  119 . The user of the syringe assembly  100  applying the forces in this manner squeezes the outer sleeve flange  139  and barrel flange  119  towards each other, moving the cap  152  off of the distal tip  118  and exposing the distal tip  118 , which can then be connected to a VAD. 
     The syringe assembly  100  is further shown as comprising a connection collar  170  surrounding the distal tip  118  and an alignment collar  172  coaxial with the connection collar  170 , the alignment collar  172  comprising a peripheral tab  174  that engages the outer sleeve  132 . The outer sleeve  132  comprises a slot  135  that cooperates with the peripheral tab  174  to align the cap  152  with the open distal end  138  of the outer sleeve  132  and to guide relative sliding movement between the barrel  102  and the outer sleeve  132 . In the embodiment shown and as best seen in  FIG. 7 , the slot  135  in the outer sleeve comprises a detent  137  to prevent unintended relative movement of the syringe barrel  102  and the outer sleeve  132 .  FIGS. 2 and 4  show the peripheral tab  174  below the detent  137  in the slot  135 , which holds the assembly in the ready to use position. The peripheral tab  174  and the detent  137  in the slot  135  are configured so that the user must exert a sufficient amount of force to advance the peripheral tab  174  past the detent  137 , causing the cap to move from the first position to the second position.  FIG. 7  shows the peripheral tab  174  after the peripheral tab  174  has been advanced past the detent  137 , having moved in a distal direction (indicated by arrow  121  in  FIG. 2 ), advancing the distal tip  118  past the open distal end  138  of the outer sleeve so that the distal tip can be connected to a VAD. In one or more embodiments, the alignment collar  172  can comprise a plurality of peripheral tabs  174 , for example, two, three, or more. The outer sleeve  132  can similarly comprise a plurality of slots  135  which cooperate with the peripheral tabs  174  to guide the outer sleeve  132  and the barrel  102  during relative sliding motion. 
     Referring now to  FIGS. 10-17 , a second embodiment of a flush syringe assembly  200  is shown. The flush syringe assembly  200  comprises a barrel  202  including a side wall  204  having an outside surface  206 , an inside surface  208  defining a chamber  210  for retaining fluid. The barrel  102  further comprises an open proximal end  112 , and a distal end  114  including a distal wall  216  with a distal tip  218  extending distally therefrom having a first passageway  220  therethrough in fluid communication with the chamber  210 . 
     The embodiment shown in  FIGS. 10-17  further comprises an outer sleeve  232  slidably engaged with the outside surface  206  of the barrel  202 , the outer sleeve  232  comprising an inner surface  234 , an outer surface  236 , and an open distal end  238  comprising a peripheral distal surface  240 . The syringe assembly  200  further comprises a removable seal  250   a  disposed on the peripheral distal surface  240 . The apparatus further comprises a cap  252  and an absorbent pad  254  containing disinfectant disposed between the removable seal  250  and the distal tip. The embodiment of  FIGS. 10-17  further comprises a fixed seal  250   b  disposed between the cap  252  and the absorbent pad  254 . The cap  252  is rotatable from a first position in which the distal tip  218  of the barrel  202  is covered by the cap  252  and a second position in which the distal tip  218  of the barrel  202  is exposed through the open distal end  238  of the outer sleeve  232 . 
     Referring now to  FIGS. 11 and 12 , relative sliding movement of the outer sleeve  232  and the barrel  202  moves the distal tip  218  of the barrel  202  and the open distal end  238  of the outer sleeve  232  closer together, which pushes the distal tip  218 , causing the distal tip to rotate the cap  252  from the first position to the second position.  FIG. 13  shows the cap  252  rotated in the direction of arrow  265  from the first position  252   a  in which the cap  252  covers the distal tip  218 , to position  252   b  as the cap  252  is rotated off of the distal tip to position  252   c  and then position  252   d  where the cap  252  is in the second position, which is an uncovered position and the distal tip  218  is exposed as shown in  FIGS. 14 and 15 . The relative sliding movement of the outer sleeve  232  and the barrel occurs when a user of the syringe assembly applies proximally directed force (in the direction of arrow  241  in  FIG. 11 ) to the outer sleeve flange  239  while applying distally directed force (in the direction of arrow  221  in  FIG. 11 ) to the barrel flange  219 . According to one or more embodiments, a user can clean a VAD with the syringe assembly  100  and then connect the syringe assembly to the VAD using one hand. For example, a user can hold the syringe assembly with cap in the first position as shown in  FIGS. 2-4  by gripping placing the outer sleeve between the index finger and middle finger of their hand. The user can then move the cap  252  and absorbent pad  254  out of the way by gripping the outer sleeve  232 , applying the proximally directed force to the outer sleeve flange  239  by placing the outer sleeve between the user&#39;s fingers and pressing the barrel flange  219  into the palm of the user&#39;s hand or thumb as desired, which applies the distally directed force to the barrel flange  219 . The user of the syringe assembly  200  applying the forces in this manner squeezes the outer sleeve flange  239  and barrel flange  219  towards each other, moving the cap  252  off of the distal tip  218  and exposing the distal tip  218 , which can then be connected to a VAD. 
     In the embodiment shown in  FIGS. 10-17 , rotation of the cap  252  pierces the fixed seal  250   b  and pushes through the absorbent pad  254 . 
     The syringe assembly  200  is further shown as comprising a connection collar  270  surrounding the distal tip  218  and an alignment collar  272  coaxial with the connection collar  270 , the alignment collar  272  comprising a peripheral tab  274  that engages the outer sleeve  232 . The outer sleeve  232  comprises a slot  235  that cooperates with the peripheral tab  274  to align the cap  252  with the open distal end  238  of the outer sleeve  232  and to guide relative sliding movement between the barrel  202  and the outer sleeve  232 . In the embodiment shown and as best seen in  FIG. 7 , the slot  235  in the outer sleeve comprises a detent  237  to prevent unintended relative movement of the syringe barrel  202  and the outer sleeve  232 .  FIGS. 11 and 12  show the peripheral tab  274  below the detent  237  in the slot  235 , which holds the assembly in the ready to use position. The peripheral tab  274  and the detent  237  in the slot  235  are configured so that the user must exert a sufficient amount of force to advance the peripheral tab  274  past the detent  237 , causing the cap to move from the first position to the second position.  FIG. 15  shows the peripheral tab  274  after the peripheral tab  274  has been advanced past the detent  237 , having moved in a distal direction (indicated by arrow  221  in  FIG. 11 ), advancing the distal tip  218  past the open distal end  238  of the outer sleeve so that the distal tip can be connected to a VAD. In one or more embodiments, the alignment collar  272  can comprise a plurality of peripheral tabs  274 , for example, two, three, or more. The outer sleeve  232  can similarly comprise a plurality of slots  235  which cooperate with the peripheral tabs  274  to guide the outer sleeve  232  and the barrel  202  during relative sliding motion. 
     In the embodiment shown in  FIGS. 10-17 , the cap  252  may include a sharpened edge  257  to aid in piercing the fixed seal  250   b  as the cap  252  is moved from the first position to the second position. The alignment collar  272  may also comprise a sharpened feature  277  such as a spike, which may also pierce the fixed seal  252  as the user squeezes the outer sleeve flange  239  and the barrel flange  219  to activate the device to expose the distal tip  218 . The absorbent pad has a thickness and may have cut pattern through the thickness to allow the cap  252  to push through the absorbent pad  254 . 
     In use, when a user of the syringe assembly  200  peels away the removable seal  250 , the absorbent pad  254  is exposed and can be used to clean or swap a VAD. During cleaning, the cap  252  is in the first position, the absorbent pad  254  is exposed through the open distal end of the outer sleeve  232 . When the cleaning is completed by the user, the user can activate the device as described above to place the cap  252  is in the second position, and the cap  252  is rotated through the open distal end  238  of the outer sleeve  232  to expose the distal tip  218  of the barrel  202 . 
     According to one or more embodiments, the removable seal of the embodiments described herein comprises an aluminum or multi-layer polymer film peel back top. The removable seal provides a liquid tight seal by a suitable adhesive that adheres the removable seal to the peripheral distal surface of the outer sleeve. The removable seal prevents the disinfectant from dissipating too quickly and facilitates long shelf life. The removable seal can be chemically-resistant, light-blocking, non-permeable, or sterile. In one or more embodiments, the connection collar comprises a Luer connector. 
     While not shown in the Figures, the syringe assembly according to one or more embodiments can further comprise a plunger rod comprising a distal end including a stopper slidably positioned in fluid-tight engagement with the inside surface of the barrel for drawing fluid into and driving fluid out of the chamber by movement of the stopper relative to the barrel. The plunger rod extends outwardly from the open proximal end of the barrel 
     The absorbent pad according to one or more embodiments soaks up the disinfectant or antimicrobial agent. The disinfectant or antimicrobial agent can be a fluid or a gel selected from the group consisting of selected from the group consisting of ethanol, 2-propanol, butanol, methylparaben, ethylparaben, propylparaben, propyl gallate, butylated hydroxyanisole (BHA), butylated hydroxytoluene, t-butyl-hydroquinone, chloroxylenol, chlorohexidine, dichlorobenzyl alcohol, dehydroacetic acid, hexetidine, triclosan, hydrogen peroxide, colloidal silver, and mixtures thereof. 
     The syringe assemblies described herein can be filled with flush solution using known methods. Additionally, the syringe assemblies may be provided pre-filled from the manufacturer or supplier. The flush solution may be any solution intended for flushing or maintaining performance of VAD&#39;s. The flush solution can be selected from suitable flush solutions such as saline flush solution and heparin lock flush solution. These solutions are known in the art and are readily available. An example of a saline flush solution includes, but is not limited to, 0.9% sodium chloride USP for injection. An example of a heparin lock flush solution includes but is not limited to 0.9% sodium chloride with 100 USP units of heparin sodium per mL or 10 USP units of heparin sodium per mL. 
     The syringe assemblies can be used in flushing a vascular access device such as a catheter or IV set. IV sets can be very complex and may include multiple injection ports, valves, and/or other components. 
     There are two general classifications of VAD&#39;s, peripheral catheters and central venous catheters. Peripheral catheters are used to access veins in the peripheral extremities such as the hand and arm. Peripheral catheters are relatively short in length ranging from about 14 mm to 48 mm in length, and are available in gauge sizes from about 16 to 24. It is believed that the most commonly used peripheral catheters are 20 gauge having an ID of about 0.81 mm (0.032 inch) and 22 gauge having an ID of about 0.66 mm (0.026 inch), and having a length of about 25 mm to 32 mm. As used herein, the term “peripheral catheter” is intended to refer to a 20 or 22 gauge catheter having a length of about 25 mm Central venous catheters are substantially longer than peripheral catheters and are inserted in the patient and terminate near the heart. 
     Another aspect of the disclosure pertains to a method of disinfecting a vascular access device. The method includes exposing an absorbent pad containing disinfectant at a distal end of a flush syringe assembly comprising a barrel having a distal tip covered by a cap, contacting the vascular access device with absorbent pad, and then rotating the cap to expose the distal tip of the barrel. The method can further comprise utilizing embodiments of the syringe assemblies described herein, for example, a syringe assembly which comprises an outer sleeve having and open distal end and a distal end face slidably engaged with the syringe barrel and the method further comprises sliding the syringe barrel and the outer sleeve with respect to each other, causing the cap to rotate away from the distal tip. Sliding the syringe barrel and the outer sleeve with respect to each other causes the cap to rotate away from the distal tip. Prior to sliding the outer sleeve and the barrel with respect to each other, a user removes a removable seal from the distal end face of the outer sleeve to expose the absorbent pad. Prior to (or after) removing the removable seal, a user can break the stopper free. After scrubbing the VAD connector, the user slides the outer sleeve to expose the syringe tip, the syringe tip is attached to the VAD connector, and the VAD is flushed. The syringe assembly is then removed after the flushing procedure and discarded. 
     Although the disclosure herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present disclosure. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present disclosure as disclosed.