Multi-barrel syringe for sequential delivery of fluids and method of use

Abstract

A multi-barrel syringe for sequentially discharging a first fluid and a subsequent second fluid includes an outer barrel containing the first fluid and an inner barrel containing the second fluid slidably inserted into the outer barrel. The outer barrel includes an open proximal end, a distal end including a fluid port, a sidewall extending between the proximal end and the distal end, and a protrusion extending into the outer barrel from an inner surface of the outer barrel. The inner barrel includes an open proximal end, a closed distal end, and a sidewall extending between the proximal end and the distal end. The inner barrel is moved through the outer barrel such that the pierceable portion of the inner barrel contacts the protrusion of the outer barrel to pierce the inner barrel, allowing the second fluid to flow from the inner barrel to the outer barrel.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Indian patent application No. 202211036491 filed on June 24, 2022, titled “Multi-Barrel Syringe for Sequential Delivery of Fluids and Methods of Use”, the entire disclosure of which is incorporated herein by reference in its entirety.

[0003] BACKGROUND OF THE INVENTION

[0004] Field of the Invention

[0005] The present disclosure relates generally to syringes for expelling multiple fluids, and more particularly to syringes for sequentially expelling a first fluid, such as a medical fluid, followed by a second fluid, such as a flushing solution.

[0006] Description of related technologies

[0007] Vascular Access Device (VAD) is a commonly used medical device that may include an intravenous (IV) catheter, such as a peripheral catheter or a central venous catheter. If improperly maintained or exposed to a non-sterile environment, the VAD may be contaminated, blocked by blood clots, and / or may spread infection. Many medical institutions implement aseptic techniques and procedures to ensure that the VAD is used correctly and will not be blocked or infected. These procedures typically include disinfecting the VAD and flushing the catheter with a flushing solution. Specifically, VAD operating standards typically recommend flushing procedures after catheter placement, before fluid infusion, and before and after drug administration, before and after blood sampling, before and after blood transfusion, and / or before and after parenteral nutrition administration.

[0008] These flushing procedures are designed to confirm catheter patency, avoid medication incompatibilities, ensure that a complete medication dose is administered to the patient, prevent thrombosis, and minimize the risk of bloodstream infection caused by contamination of the VAD. In addition, flushing can prevent the accumulation of blood, blood residue, and IV medications within the catheter or other VAD device. Such accumulation may cause the fluid pathway in the catheter system to become partially or completely blocked, which may require the practitioner to perform certain expensive and potentially dangerous procedures to clear the affected catheter, or may require the practitioner to replace the blocked catheter with a new catheter. Often, such blockages result in interruptions in treatment, which may impact patient care. The accumulation of residue within the catheter may also increase the risk of infection.

[0009] During the administration of a drug or another medical fluid, the catheter or VAD is typically flushed before and after the fluid is delivered to the VAD from a syringe or another drug delivery device. In some cases, a syringe assembly prefilled with various fluids (referred to herein as flushing solutions) can be used to flush the catheter. The size of the prefilled syringe for flushing the catheter varies based on, for example, the size and length of the catheter. Typically, the prefilled syringe for flushing the catheter or IV line contains about 1 mL, 3 mL, 5 mL, or 10 mL of flushing solution. Many different syringes available from different manufacturers can be used to provide flushing solutions through the patient's catheter or IV line, including, for example, the BD PosiFlush from Becton, Dickinson and Company. TM Pre-filled saline syringe.

[0010] In order to perform the flushing procedure, the practitioner connects the pre-filled flushing syringe to the VAD and advances the plunger rod into the barrel of the pre-filled syringe, which discharges the flushing solution to the VAD through the nozzle or fluid port of the pre-filled syringe. After flushing, the pre-filled syringe is disconnected from the VAD so that the practitioner can apply a dose of medical fluid. The medical fluid is usually contained in a vial and drawn into a separate syringe, which is connected to the VAD after being filled with the medical fluid. Then, the medical fluid is injected into the VAD by advancing the plunger rod through the syringe containing the medical fluid. After the medical fluid is injected into the VAD, the syringe is disconnected from the VAD and the VAD is flushed using a second pre-filled flushing syringe. Flushing the VAD after applying the medical fluid confirms the patency of the catheter, and any remaining medical fluid in the catheter is delivered to the patient, thereby ensuring that the full dose of the medical fluid is delivered to the patient.

[0011] Connecting or disconnecting a syringe or other device to a VAD introduces portions of the VAD to a non-sterile external environment, which increases the likelihood that the VAD will be contaminated and / or become a source of bloodstream infection. In order to reduce the risk of bloodstream infection and ensure proper use and maintenance of the VAD, operating standards require that any fluid ports or connectors of the VAD be disinfected and cleaned each time a new syringe is connected to the VAD. Thus, by reducing the number of times portions of the VAD must be disinfected and cleaned, reducing the number of syringes that must be connected to the VAD during drug delivery simplifies drug administration. Reducing the number of syringes or other fluid delivery devices used during a procedure also reduces the chances that portions of the VAD will become contaminated, thereby reducing the risk of bloodstream infection. The syringes and methods of the present disclosure simplify the process by reducing the number of syringes used during a drug administration procedure, thereby reducing the risk of contamination and bloodstream infection. Summary of the invention

[0012] According to one aspect of the present disclosure, a multi-barrel syringe for sequentially discharging at least a first fluid and a subsequent second fluid comprises an outer barrel configured to accommodate the first fluid and an inner barrel configured to accommodate the second fluid slidably inserted into the outer barrel. The outer barrel comprises an open proximal end, a distal end comprising a fluid port, a sidewall extending between the proximal end and the distal end, and at least one projection extending from the inner surface of the outer barrel to the inside of the outer barrel. The inner barrel comprises an open proximal end, a closed distal end, and a sidewall extending between the proximal end and the distal end. The inner barrel is moved through the outer barrel so that the pierceable portion of the inner barrel contacts the at least one projection of the outer barrel to pierce the inner barrel, thereby allowing the second fluid to flow from the inner barrel to the outer barrel. The syringe also includes a plunger at least partially inserted into the inner barrel, the plunger for moving the inner barrel through the outer barrel, and for moving through the inner barrel to expel the second fluid from the inner barrel through the pierceable portion of the inner barrel.

[0013] According to another aspect of the present disclosure, a prefilled flushing syringe includes any of the aforementioned syringes of the present disclosure, wherein the inner cylinder is at least partially inserted into the outer cylinder, and the plunger is at least partially inserted into the inner cylinder. The prefilled syringe also includes a predetermined volume of a second fluid located in the inner cylinder, and the second fluid is sealed in the inner cylinder by the plunger.

[0014] According to another aspect of the present disclosure, a method for sequentially expelling fluid from one of the aforementioned syringes includes: applying distal pressure to the plunger to move the inner barrel through the outer barrel to expel the first fluid from the outer barrel through the fluid port. The method also includes: once the pierceable portion of the inner barrel is pierced by the at least one protrusion of the outer barrel, continuing to apply distal pressure to the plunger to move the plunger through the inner barrel to expel the second fluid from the inner barrel to the outer barrel and through the fluid port.

[0015] Non-limiting illustrative examples of embodiments of the present disclosure will now be described in the following numbered items.

[0016] Article 1: A multi-barrel syringe for sequentially discharging at least a first fluid and a subsequent second fluid, the syringe comprising: an outer barrel configured to contain the first fluid, the outer barrel comprising an open proximal end, a distal end comprising a fluid port, a sidewall extending between the proximal end and the distal end, and at least one protrusion extending from an inner surface of the outer barrel into an interior of the outer barrel; an inner barrel configured to contain the second fluid, the inner barrel being slidably insertable into the outer barrel, the inner barrel comprising an open proximal end, a distal end comprising a fluid port, a sidewall extending between the proximal end and the distal end, and at least one protrusion extending from an inner surface of the outer barrel into an interior of the outer barrel; and an inner barrel configured to contain the second fluid, the inner barrel being slidably insertable into the outer barrel, the inner barrel comprising an open a proximal end, a closed distal end, and a sidewall extending between the proximal end and the distal end, wherein the inner cylinder is moved through the outer cylinder so that the pierceable portion of the inner cylinder contacts the at least one protrusion of the outer cylinder to pierce the inner cylinder, thereby allowing the second fluid to flow from the inner cylinder to the outer cylinder; and a plunger at least partially inserted into the inner cylinder, the plunger being used to move the inner cylinder through the outer cylinder and to move through the inner cylinder to discharge the second fluid from the inner cylinder through the pierceable portion of the inner cylinder.

[0017] Clause 2: The syringe of clause 1, wherein, when the pierceable portion of the inner barrel is intact, applying pressure to the plunger causes the inner barrel to move through the outer barrel.

[0018] Clause 3: The syringe of clause 1 or clause 2, wherein, when the pierceable portion of the inner barrel is intact, applying proximal pressure to the plunger causes the inner barrel to move proximally through the outer barrel to draw the first fluid into the outer barrel through the fluid port.

[0019] Article 4: A syringe according to any one of Articles 1 to 3, wherein, when the pierceable portion of the inner barrel is intact, applying distal pressure to the plunger causes the inner barrel to move distally through the outer barrel to expel the first fluid from the outer barrel through the fluid port.

[0020] Clause 5: The syringe of any one of clauses 1 to 4, wherein after the pierceable portion of the inner barrel is pierced by the at least one protrusion, distal pressure is applied to the plunger to move the plunger through the inner barrel.

[0021] Clause 6: The syringe according to any one of Clauses 1 to 5, wherein the inner barrel and the outer barrel comprise at least one of polyester, polycarbonate, polypropylene, polyethylene, polyethylene terephthalate, or acrylonitrile butadiene styrene.

[0022] Clause 7: The syringe of any one of Clauses 1 to 6, wherein the inner barrel includes a finger flange extending radially from the open proximal end of the inner barrel, and the outer barrel includes a finger flange extending radially outward from the outer barrel.

[0023] Clause 8: The syringe of any one of Clauses 1 to 7, wherein the distal end of the inner barrel comprises an annular flange configured to contact an inner surface of the outer barrel.

[0024] Clause 9: The syringe of any one of clauses 1 to 8, wherein the inner barrel includes a stopper mounted to the distal end of the inner barrel, the stopper being sized to seal against the inner surface of the sidewall of the outer barrel.

[0025] Clause 10: The syringe of clause 9, wherein the stopper comprises a full stopper that covers the distal end of the inner barrel and a portion of the side wall of the inner barrel.

[0026] Clause 11: The syringe of clause 9 or clause 10, wherein the stopper comprises an annular partial stopper that partially covers the distal end of the inner barrel.

[0027] Clause 12: The syringe of any one of Clauses 1 to 11, wherein the pierceable portion of the inner barrel comprises a groove in the closed distal end of the inner barrel.

[0028] Item 13: The syringe of Item 12, wherein the thickness of the groove is less than the thickness of other portions of the closed distal end of the inner barrel.

[0029] Clause 14: The syringe of Clause 12 or 13, wherein the groove comprises an annular groove positioned to be contacted by a plurality of protrusions extending inwardly from the distal end of the outer barrel.

[0030] Clause 15: The syringe of any one of Clauses 1 to 14, wherein the plunger comprises a stopper slidably positioned in the inner barrel and a plunger rod connected to and extending proximally from the stopper.

[0031] Clause 16: The syringe of clause 15, wherein the stopper comprises a thermoplastic elastomer, such as isoprene.

[0032] Clause 17: The syringe of clause 15 or clause 16, wherein the plunger rod comprises a press plate at the proximal end of the plunger rod.

[0033] Clause 18: The syringe of any one of Clauses 15 to 17, wherein the stopper comprises a frustoconical distal surface and at least one annular rib configured to seal against the inner surface of the sidewall of the inner barrel.

[0034] Clause 19: The syringe of any one of clauses 1 to 18, wherein the at least one protrusion comprises at least one of a spike, a needle, a ridge, a sharp, a point, or a post.

[0035] Clause 20: The syringe of any one of Clauses 1 to 19, wherein the at least one protrusion is integral with the remainder of the outer barrel.

[0036] Clause 21: The syringe of clause 20, wherein the outer barrel including the at least one protrusion is an integrally molded component.

[0037] Clause 22: The syringe of any one of Clauses 1 to 21, wherein the at least one protrusion extends inwardly from the inner surface of the distal end of the outer barrel.

[0038] Clause 23: The syringe of clause 22, wherein the outer barrel comprises a plurality of protrusions extending inwardly from the distal end of the outer barrel.

[0039] Clause 24: A syringe according to any one of Clauses 1 to 23, wherein the at least one protrusion comprises at least one channel for fluid to flow from the inner barrel to the outer barrel after the pierceable portion of the inner barrel is pierced.

[0040] Clause 25. The syringe of Clause 24, wherein the at least one channel comprises at least one of a groove, notch, opening, slot, cutout, cavity, or lumen extending at least partially through the at least one protrusion.

[0041] Article 26: The syringe according to any one of Articles 1 to 25, further comprising a removable cap engaged to the outer barrel and / or the inner barrel, the removable cap being used to prevent the inner barrel from being fully inserted into the outer barrel when the cap is engaged.

[0042] Clause 27: The syringe of clause 26, wherein the removable cap, when engaged to the inner barrel and / or the outer barrel, prevents the pierceable portion of the inner barrel from contacting and being pierced by the at least one protrusion of the outer barrel.

[0043] Clause 28. The syringe of Clause 26 or Clause 27, wherein the removable cap is removably engaged to a finger flange extending radially outward from the proximal end of the outer barrel.

[0044] Article 29: A prefilled flushing syringe, comprising: a syringe according to any one of Articles 1 to 28, wherein the inner barrel is at least partially inserted into the outer barrel, and the plunger is at least partially inserted into the inner barrel; and a predetermined volume of the second fluid is located in the inner barrel, and the second fluid is sealed in the inner barrel by the plunger.

[0045] Clause 30: The prefilled syringe of clause 29, wherein the second fluid is a saline flush solution.

[0046] Clause 31: A prefilled syringe according to clause 29 or clause 30, further comprising a removable cap engaged to the outer barrel and / or the inner barrel, the removable cap being used to prevent the inner barrel from being fully inserted into the outer barrel when the cap is engaged.

[0047] Article 32: A method for sequentially expelling fluid from a syringe according to any one of Articles 1 to 28, the method comprising: applying distal pressure to the plunger to move the inner barrel through the outer barrel to expel the first fluid from the outer barrel through the fluid port; and once the pierceable portion of the inner barrel is pierced by the at least one protrusion of the outer barrel, continuing to apply distal pressure to the plunger to move the plunger through the inner barrel to expel the second fluid from the inner barrel into the outer barrel and through the fluid port.

[0048] Clause 33: The method of clause 32, further comprising initially applying a proximal pressure to the plunger to move the inner barrel proximally through the outer barrel to draw the first fluid into the outer barrel.

[0049] Clause 34: The method of clause 33, wherein drawing the first fluid further comprises: attaching a needle to a fluid port of a fluid container, inserting the needle into the fluid container, and drawing the first fluid from the fluid container into the outer cylinder.

[0050] Clause 35: The method of any one of Clauses 32 to 34, wherein the syringe is configured to be partially pre-filled to contain a predetermined volume of the second fluid in the inner barrel.

[0051] Clause 36: The method of any one of Clauses 32 to 35, further comprising: attaching at least one patient line to the fluid port of the syringe before expelling the first fluid from the outer barrel through the fluid port.

[0052] Clause 37: The method of any one of Clauses 32 to 36, wherein the second fluid comprises a flushing solution, such as a saline solution and / or a heparin lock flushing solution, and the first fluid comprises a therapeutic agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1A is a perspective cross-sectional view of a multi-barrel syringe in an initial partially filled state for sequentially delivering a first fluid and subsequently a second fluid according to one aspect of the present disclosure.

[0054] Figure 1B It is in a filled state Figure 1A Cross-sectional view of a multi-barrel syringe.

[0055] Figure 1C yes Figure 1A Exploded view of a multi-barrel syringe.

[0056] Figure 2A It is partially filled Figure 1A Cross-sectional view of a multi-barrel syringe.

[0057] Figure 2B It is in a filled state Figure 1A Cross-sectional view of a multi-barrel syringe.

[0058] Figure 2C It is used to discharge fluid from a syringe. Figure 1A Cross-sectional view of a multi-barrel syringe.

[0059] Figure 2D Is in its final state or after use Figure 1A Cross-sectional view of a multi-barrel syringe.

[0060] Figure 3A According to one aspect of the present disclosure Figure 1A An enlarged view of the distal portion of the outer barrel of a multi-barrel syringe of FIG. 1 showing a protrusion extending from the distal surface of the barrel.

[0061] Figure 3B and Figure 3C According to one aspect of the present disclosure Figure 1A Additional views of the distal portion of the multi-barrel syringe showing the protrusions of the outer barrel piercing the inner barrel.

[0062] Figure 4A and Figure 4B are cross-sectional views of portions of additional exemplary multi-barrel syringes including stops connected to the inner barrels of the syringes according to aspects of the present disclosure.

[0063] Figure 5is a flow chart illustrating the steps of using a multi-barrel syringe to draw and expel fluid from the syringe according to an aspect of the present disclosure. DETAILED DESCRIPTION

[0064] The following description is provided to enable those skilled in the art to make and use the described embodiments intended for implementing the present invention. However, various modifications, equivalents, variations and substitutes will be apparent to those skilled in the art. Any and all such modifications, variations, equivalents and substitutes are intended to fall within the spirit and scope of the present invention.

[0065] Hereinafter, for the purpose of description, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal" and their derivatives shall relate to the present invention as oriented in the accompanying drawings. As used herein, the term "proximal" refers to the portion or end of a device (such as a syringe or catheter) that is grasped, manipulated, or used by a practitioner or other user. The term "distal" refers to the end or portion of a device that is farthest from the portion of the device that is grasped, manipulated, or used by a practitioner. For example, the "proximal end" of a catheter or IV line refers to the end that includes a fluid port connected to a fluid container (such as an IV bag or a syringe). The "distal end" of a catheter or IV line refers to the end that is connected to the patient. However, it should be understood that the present invention may employ alternative variations and step sequences unless otherwise expressly stated. It should also be understood that the specific devices and processes shown in the drawings and described in the following specification are merely exemplary embodiments of the present invention. Therefore, specific dimensions and other physical characteristics associated with the embodiments disclosed herein should not be considered limiting.

[0066] With reference to the accompanying drawings, the present disclosure relates to multi-barrel syringes 10, 210 that discharge a first fluid F1 and a subsequent second fluid F2 from a chamber or barrel of the syringe 10, 210 through a fluid port or nozzle of the syringe 10, 210 to, for example, a vascular access device. The first fluid F1 can be a medical fluid, which, as used herein, can refer to a drug, a total parenteral nutrition (TPN) liquid, or another therapeutic agent known in the art for treating a chronic or acute condition. Exemplary therapeutic agents can include, for example, drugs, chemicals, or biological or biochemical substances that achieve a desired therapeutic effect when delivered to a patient in a therapeutically effective amount. The second fluid F2 can be a flushing solution, such as saline and / or a heparin lock flushing solution. An example of a saline flushing solution is 0.9% sodium chloride USP for injection. An example of a heparin lock flush solution is 0.9% sodium chloride with 100 USP units of heparin sodium per milliliter or 0.9% sodium chloride with 10 USP units of heparin sodium per milliliter. Other flush solutions known in the art may also be used with the syringes 10, 210 of the present disclosure. The syringes 10, 210 may also be used to sequentially deliver a first drug or therapeutic agent and a subsequent different second drug or therapeutic agent.

[0067] The syringe 10, 210 of the present disclosure allows practitioners (such as medical technicians, nurses, physician assistants, doctors or other trained or untrained clinicians or medical caregivers) to apply, for example, medicines and subsequent flushing solutions without having to replace syringes between the delivery of the first fluid and the second fluid. Advantageously, the sequential delivery of medicines and subsequent flushing solutions is automatically performed by, for example, the advancement of the plunger rod of the syringe 10, 210. As used herein, the "advancement" of the plunger rod means that the practitioner is able to push the plunger rod through the barrel of the syringe 10, 210 in the distal direction to discharge the first fluid F1 and the subsequent second fluid F2 from the syringe 10, 210 as a single stroke. The practitioner does not need to disconnect the syringe or another device from the VAD, for example, between the delivery of the first fluid and the second fluid. In addition, when using the syringe 10, 210 of the present disclosure, the practitioner does not need to change the direction of movement of the plunger rod, nor does it need to press another component or mechanism of the syringe 10, 210 to perform the sequential delivery of the first fluid and the second fluid.

[0068] In some examples, the syringe 10, 210 is provided as a partially pre-filled syringe, wherein the chamber or barrel of the syringe 10, 210 is filled with a flushing solution during manufacture. The partially pre-filled syringe 10, 210 may include a cap, a clip, a retainer, and / or other packaging to hold the plunger rod in place and ensure that the flushing solution does not leak from the partially pre-filled syringe 10, 210 at an unexpected time (such as during shipping).

[0069] The syringes 10, 210 of the present disclosure are also configured to allow a practitioner to draw a medical fluid into the syringe 10, 210 before delivering the fluid to a patient. For example, a practitioner may insert the nozzle or needle of the syringe 10, 210 into a bottle containing the medical fluid and then draw the medical fluid into the fluid chamber or barrel of the syringe 10, 210 by moving the plunger rod of the syringe 10, 210 in a proximal direction. After the medical fluid is drawn into the fluid chamber or barrel of the syringe 10, 210, sequential delivery of a first fluid F1 and subsequently a second fluid F2 may be performed by connecting the syringe 10, 210 to a fluid port of a VAD and then moving the plunger rod of the syringe 10, 210 in a distal direction, thereby expelling the first fluid and subsequently the second fluid from the syringe 10, 210 to the VAD.

[0070] Compared to conventional fluid application operations, the syringe 10, 210 of the present disclosure simplifies the fluid application procedure, thereby saving a significant amount of time, since there is no need to clean or disinfect some parts of the VAD between the delivery of the first fluid and the second fluid. The syringe 10, 210 of the present disclosure also reduces the risk of infection and allows the VAD to be flushed immediately after the medical fluid is applied, which can prevent the drug from being blocked in the VAD. In addition, the syringe 10, 210 of the present disclosure has zero dead space, which means that when the second fluid (e.g., flushing solution) moves to the VAD through the syringe 10, 210, all of the medical fluid contained in the first chamber of the syringe 10, 210 is flushed out of the syringe 10, 210.

[0071] Multi-barrel syringes for sequential drug delivery

[0072] Figures 1A to 2DThe example of the multi-barrel syringe 10 for sequentially discharging at least the first fluid F1 and the subsequent second fluid F2 is shown. As described above, the first fluid F1 can be a medical fluid, such as a medicine or another therapeutic agent intended to be delivered to the patient by a VAD (such as a catheter or IV line). The second fluid F2 can be a flushing solution, such as a physiological saline solution and / or an anticoagulant (such as heparin). The type of flushing solution contained in the syringe 10 and the amount of the flushing solution can vary according to the specific type of the catheter or IV line being used, for example. In some examples, the syringe 10 contains or is configured to contain about 1mL and 20mL of the second fluid F2, or preferably, about 5mL and about 10mL of the second fluid F2.

[0073] The syringe 10 includes an outer barrel 12 configured to accommodate a first fluid F1 and an inner barrel 14 configured to accommodate a second fluid F2, the inner barrel 14 being slidably inserted into the outer barrel 12. The outer barrel 12 may include an open proximal end 16, a distal end 18 including a fluid port 20, and a sidewall 22 extending between the proximal end 16 and the distal end 18. The fluid port 20 of the outer barrel 12 may be a connector (such as a Luer connector, a threaded connector, or a snap connector) configured to be connected to a needle that is used to access the interior of a medical bottle containing a medical fluid, for example. The fluid port 20 of the outer barrel 12 may also be configured to be directly or indirectly connected to a fluid port, a valve, or another end access portion of a VAD. For example, a common type of fluid port for a VAD is a pierceable septum or pre-slit septum made of rubber or another elastomeric material that allows insertion of a sharp or blunt needle cannula to infuse or withdraw fluid from the catheter of the VAD. Another common fluid port for a VAD is a valve that does not require a needle to access the VAD. Instead, the valve can be activated by a frustoconical tip of a syringe barrel to provide fluid communication between the interior of the barrel and the VAD.

[0074] The outer barrel 12 also includes one or more protrusions 24 extending from the inner surface of the sidewall 22 of the outer barrel 12 into the interior of the outer barrel 12. As described in further detail herein, the protrusions 24 can be, for example, spikes, needles, ridges, sharp objects, points, posts, or similar protruding members extending into the interior of the outer barrel 12 for piercing the inner barrel 14. In some examples, the protrusions 24 extend proximally from the inner surface of the distal end 18 of the outer barrel 12. In other examples, one or more of these protrusions 24 can extend radially inward from the inner surface of the sidewall 22 of the outer barrel 12.

[0075] In some examples, the outer barrel 12 of the syringe 10 can be roughly similar in shape, size, and construction to the barrel of a syringe for administering flushing solutions to a VAD known in the art. For example, the outer barrel 12 can be a cylindrical structure formed of a rigid thermoplastic material, such as polyester, polycarbonate, polypropylene, polyethylene, polyethylene terephthalate, acrylonitrile butadiene styrene, or other injection moldable or formable resin materials known in the art. For example, an exemplary barrel for flushing a syringe is described in U.S. Patent Application Publication No. 2020 / 0061297, entitled “Flush Syringe Assembly with Controlled Pulsatile Flushing,” which is incorporated herein by reference in its entirety.

[0076] The inner barrel 14 of the syringe 10 may be similar in shape and configuration to the outer barrel 12, but slightly narrower than the outer barrel 12. In particular, the inner barrel 14 may have an outer diameter slightly smaller than the inner diameter of the outer barrel 12, so that the inner barrel 14 may slide through the outer barrel 12. The inner barrel 14 includes an open proximal end 26, a closed distal end 28, and a sidewall 30 extending between the proximal end 26 and the distal end 28. The inner barrel 14 is configured such that moving the inner barrel 14 through the outer barrel 12 pushes the first fluid F1 in the outer barrel 12 through the fluid port 20 and causes the pierceable portion 32 of the inner barrel 14 to contact the protrusion 24 of the outer barrel 12 to pierce the inner barrel 14. Once the inner barrel 14 is pierced, the second fluid F2 in the inner barrel 14 flows from the interior of the inner barrel 14 through the pierceable portion 32 to the outer barrel 12.

[0077] To ensure that the inner cylinder 14 moves all or substantially all of the first fluid F1 in the outer cylinder 12 toward the fluid port 20, the inner cylinder 14 may include an annular flange 34 configured to contact and / or seal against an inner surface of the sidewall 22 of the outer cylinder 12. For example, Figures 1A to 1C As shown, the inner barrel 14 includes a flange 34 extending radially outward from the distal end 28 of the inner barrel 14. In other examples, an annular flange 34 may be provided that extends radially from the sidewall 30 of the inner barrel 14. In some examples, there may be a plurality of annular flanges 34 extending from the distal end 28 and / or the sidewall 30 of the inner barrel 14 to increase the stability of the inner barrel 14 and / or enhance the seal between the inner barrel 14 and the inner surface of the sidewall 22 of the outer barrel 12 as the inner barrel 14 moves through the outer barrel 12.

[0078] Continue to refer Figures 1A to 2D, the barrels 12, 14 may include handles, flanges, supports, and the like to make the syringe 10 easier to hold and manipulate by a practitioner. For example, the inner barrel 14 may include a finger flange 36 extending radially outward from the open proximal end 26 of the inner barrel 14. Similarly, the outer barrel 12 includes a finger flange 38 extending radially outward from the outer barrel 12. The practitioner may grasp the finger flanges 36, 38, for example, between the ring and middle fingers, to draw fluid into or expel fluid from the syringe 10.

[0079] The syringe 10 also includes a plunger 40 that is slidably inserted into the inner barrel 14. The plunger 40 includes a stopper 42 that is slidably positioned in the inner barrel 14 and a plunger rod 44 that is connected to the stopper 42 and extends proximally from the stopper 42. As previously described, the stopper 42 and the plunger rod 44 are configured to move the inner barrel 14 through the outer barrel 12 to discharge the first fluid F1 from the outer barrel 12 through the fluid port 20. The plunger rod 44 and the stopper 42 are also configured to move through the inner barrel 14 to discharge the second fluid F2 from the interior of the inner barrel 14 to the outer barrel 12 through the pierceable portion 32 of the inner barrel 14. More specifically, as described herein in conjunction with FIG. 2A to FIG. 2D As further described in detail, the inner barrel 14 and the plunger 40 can be arranged such that when the pierceable portion 32 of the inner barrel 14 is intact, applying pressure to the plunger rod 44 causes the inner barrel 14 to move through the outer barrel 12. In particular, when the pierceable portion 32 of the inner barrel 14 is intact, applying proximal pressure to the plunger rod 44 causes the inner barrel 14 to move proximally through the outer barrel 12 to draw the first fluid F1 into the outer barrel 12 through the fluid port 20. In a similar manner, when the pierceable portion 32 of the inner barrel 14 is intact, applying distal pressure to the plunger rod 44 causes the inner barrel 14 to move distally through the outer barrel 12 to expel the first fluid F1 from the outer barrel 12 through the fluid port 20. After the pierceable portion 32 of the inner barrel 14 is pierced by the protrusion 24 , applying distal pressure to the plunger rod 44 causes the plunger rod 44 and the stopper 42 to move through the inner barrel 14 .

[0080] The stopper 42 may include many features of conventional syringe stops or plungers known in the art. For example, the stopper 42 may be formed of a thermoplastic elastomer material (such as polypropylene or polyethylene) and formed of a synthetic or natural rubber (e.g., isoprene). The stopper 42 may include a proximal surface 46 or proximal end, a distal surface 48 or distal end, and an outer peripheral surface 50 extending between the proximal surface 46 and the distal surface 48. In some examples, the distal surface 48 or distal end of the stopper 42 may be conical or frustoconical to facilitate the discharge of the second fluid F2 from the inner barrel 14 through the pierceable portion 32 of the inner barrel 14. Alternatively, the distal surface 48 or distal end of the stopper 42 may be substantially flat. The stopper 42 may also include one or more annular ribs 52 protruding from the outer peripheral surface 50. The annular rib 52 is configured to seal against the inner surface of the sidewall 30 of the inner cylinder 14 to ensure that the inner cylinder 14 moves with the plunger rod 44 when the pierceable portion 32 of the inner cylinder 14 is intact, and to ensure that the second fluid F2 moves through the inner cylinder 14 in an expected manner after piercing the pierceable portion 32 of the inner cylinder 14. In some examples, the stopper 42 can include multiple annular ribs 52 to improve stability and prevent the stopper 42 from tilting, shifting, or otherwise deforming when the stopper moves through the inner cylinder 14.

[0081] The plunger rod 44 is connected to the stopper 42 and extends proximally from the stopper 42. The plunger rod 44 can be, for example, an injection molded component formed of a rigid thermoplastic material, such as polyester, polycarbonate, polypropylene, polyethylene, polyethylene terephthalate, or another thermoplastic material known in the art. The plunger rod 44 includes a distal end 54 that is engaged to the stopper 42. For example, the distal end 54 of the plunger rod 44 can include a connector 56 that is inserted into a corresponding cavity 58 or slot on the proximal surface 46 of the stopper 42. The plunger rod 44 also includes a proximal end 60 that protrudes proximally from the proximal end 26 of the inner barrel 14. The proximal end 60 of the plunger rod 44 can include a thumb press plate 62 that is used to manipulate the plunger rod 44 to move the stopper 42 and / or the inner barrel 14. Within the scope of the present disclosure, the plunger rod 44 can have various cross-sectional shapes and configurations. For example, the plunger rod 44 may have a generally cross-shaped cross-section. In other examples, the plunger rod 44 may have an I-beam shape, a hollow circle, a hollow square, a hollow rectangle, or an L-shape in cross-section.

[0082] like Figure 1A and Figure 1CAs most clearly shown in , the syringe 10 may also include a removable cap 64 that is engaged to the outer barrel 12 or the inner barrel 14 to prevent the inner barrel 14 from being fully inserted into the outer barrel 12 until the cap 64 is removed. In particular, the cap 64 can be configured to maintain separation between the pierceable portion 32 of the inner barrel 14 and the protrusion 24 of the outer barrel 12 until the cap 64 is removed. Thus, the removable cap 64, when engaged to the inner barrel 14 and / or the outer barrel 12, prevents the pierceable portion 32 of the inner barrel 14 from contacting and being pierced by the protrusions 24 of the outer barrel 12. Figure 1C As shown, the removable cap 64 can be a c-shaped structure including a central opening 66 that is sized to fit around the outer barrel 12 or the inner barrel 14. The cap 64 also includes vertically extending vertical walls 68 or tabs that are used to contact a portion of the inner barrel 14 or the outer barrel 12 to maintain the spacing between the inner barrel 14 and the outer barrel 12. The cap 64 can also include a slot 70 or opening that is sized to fit over the finger flanges 36, 38 of the inner barrel 14 or the outer barrel 12. For example, as Figure 1A As shown, the removable cap 64 is inserted over the finger flange 38 of the outer barrel 12 and is positioned so that the vertical wall 68 or tab contacts the finger flange 36 of the inner barrel 14 , thereby preventing the inner barrel 14 from being fully inserted into the outer barrel 12 .

[0083] FIG. 3A to FIG. 3C An enlarged view of the distal portion of the syringe 10 is shown, focusing on the protrusion 24 of the outer barrel 12 and the pierceable portion 32 of the inner barrel 14. As previously described, the inner barrel 14 includes a closed distal end 28. Figure 3B and Figure 3C As shown, the closed distal end 28 is generally flat, or may include a slight taper that slopes toward the center of the inner barrel 14. Figure 3B and Figure 3C As shown, the inner cylinder 14 includes a flange 34 that extends radially outward from the closed distal end 28 of the inner cylinder 14 to contact the inner surface of the side wall 22 of the outer cylinder 12. As previously described, the inner cylinder 14 also includes a pierceable portion 32, such as Figure 3B and Figure 3C As shown, the pierceable portion 32 can be positioned on the closed distal end 28 of the inner barrel 14. In some examples, the pierceable portion 32 is a groove located on the closed distal end 28 of the inner barrel 14, which is thinner than other portions of the closed distal end 28. The groove can be an annular or circular groove that is positioned to be contacted by a plurality of protrusions 24 extending inwardly from the distal end 18 of the outer barrel 12.

[0084] like FIG. 3A to FIG. 3CAs shown, the protrusion 24 of the outer barrel 12 extends proximally from the distal end 18 of the outer barrel 12. For example, Figure 3A As shown, the outer barrel 12 includes a plurality of prongs or spikes extending proximally from the inner surface of the distal end 18 of the outer barrel 12. A plurality of protrusions 24 are positioned around or surround the fluid port 20 of the outer barrel 12. The protrusions 24 (such as prongs or spikes) can be integral with other portions of the outer barrel 12. For example, the outer barrel 12 including the protrusions can be an integrally molded component formed, for example, by a single injection molding process. In some examples, the protrusion 24 includes a channel 72 extending at least partially through the protrusion 24, such as a groove, notch, opening, slot, cut, cavity, or lumen. The channel 72 is configured to allow fluid to flow from the inner barrel 14 to the outer barrel 12 after the pierceable portion 32 of the inner barrel 14 is pierced. In particular, as described above, and as FIG. 3A to FIG. 3C As shown, the distal end 28 of the inner barrel 14 is initially spaced apart from the distal end 18 of the outer barrel 12. Figure 3B As shown, the inner barrel 14 is moved distally through the outer barrel 12 so that the protrusion 24 of the outer barrel 12 contacts and pierces the pierceable portion 32 (e.g., annular groove) located at the distal end 28 of the inner barrel 14. Figure 3C As shown, after the inner barrel 14 is pierced, the fluid can flow through the channel 72 of the protrusion 24 to flow from the inner barrel 14 to the outer barrel 12. Once the fluid is in the outer barrel 12, it can be discharged from the syringe 10 through the fluid port 20 of the outer barrel 12.

[0085] Method for discharging fluid from a multi-chamber syringe

[0086] As previously described, the syringe 10 is used to sequentially discharge fluids, such as discharge a medical fluid from the syringe 10 into the VAD and then discharge a flushing solution from the syringe 10 into the VAD. Figure 5 The following flow chart is shown: This flow chart shows the steps of a sequential fluid expulsion process using the syringe 10 of the present disclosure.

[0087] like Figure 5 As shown, at step 110, the practitioner first obtains a partially filled syringe 10, wherein the inner barrel 14 of the syringe 10 is filled with a predetermined volume of a second fluid F2 (such as a flushing solution). For example, the partially filled syringe 10 can contain about 1 mL to about 20 mL, or preferably about 5 mL to 10 mL of flushing solution. Figure 2A The syringe 10 is shown in an initial or partially filled state. At step 112, the practitioner prepares the syringe 10 for use, for example by removing any packaging (such as the tip cap 74) (such as Figure 1BThe practitioner may also move the plunger rod 44 in the distal direction (as shown) to remove the plunger rod 44 from the syringe 10 to prepare the syringe 10 for use. Figure 2A The inner cylinder 14 is moved as far as possible into the outer cylinder 12 without the inner cylinder 14 contacting the protrusion 24 extending from the outer cylinder 12. In particular, as described above, Figure 2A The removable cap 64 attached to the finger flange 38 of the outer barrel 12 prevents the inner barrel 14 from contacting the protrusion 24. At step 114, the practitioner places the outer barrel 12 in fluid communication with the interior of a container containing a medical fluid to be delivered to a patient. For example, the practitioner can attach a needle (not shown) to the fluid port 20 at the distal end 18 of the outer barrel 12 and insert the needle into a container (such as a medical bottle) containing a medical fluid to be injected into a patient.

[0088] At step 116, the practitioner draws a medical fluid (e.g., the first fluid F1) into the outer barrel 12. For example, the practitioner may grasp the outer barrel 12 and the plunger rod 44 (e.g., contacting the finger flange 38 of the outer barrel 12 with two fingers and contacting the pressing plate 62 of the plunger rod 44 with the thumb) and move the outer barrel 12 and the plunger rod 44 in a proximal direction (e.g., Figure 2A The plunger rod 44 is moved upward (as shown by the arrow P in the middle), which moves the inner cylinder 14 in the proximal direction, thereby sucking or extracting the fluid from the interior of the container into the interior of the outer cylinder 12, as shown in FIG. Figure 2A As shown by arrow A1. Figure 2B 1 is shown in its fully filled position, with the first fluid F1 located in the interior of the outer cylinder 12 and the second fluid F2 located in the interior of the inner cylinder 14 .

[0089] Once a dose of the medical fluid (first fluid F1) to be delivered to the patient is drawn into the outer barrel 12, at step 118, the practitioner removes the needle from the fluid port 20 of the outer barrel 12 and connects the fluid port 20 to the VAD. For example, the practitioner can insert the nozzle of the outer barrel 12 into a corresponding port or valve of the VAD to establish fluid communication between the outer barrel 12 and the inner cavity of the VAD. At step 120, once the syringe 10 is properly connected to the VAD, the practitioner grasps the plunger rod 44 (e.g., by placing the thumb on the compression plate 62 and the other fingers on the finger flange 38 of the outer barrel 12) and moves in the distal direction (e.g., Figure 2B The inner barrel 14 is pushed upwardly (as indicated by arrow D in FIG. 1 ), which causes the inner barrel 14 to move distally through the outer barrel 12. The distal movement of the inner barrel 14 causes the first fluid F1 (e.g., medical fluid) in the outer barrel 12 to be discharged to the VAD through the fluid port 20 of the outer barrel 12, as shown in FIG. Figure 2BThe practitioner continues to move the plunger rod 44 in the distal direction until the inner barrel 14 presses against the removable cap 64 engaged with the finger flange 38 of the outer barrel 12, indicating that most or all of the first fluid F1 has been expelled from the outer barrel 12. Figure 2C , the syringe 10 is shown in a position in which the inner barrel 14 contacts the cap 64.

[0090] At step 122, the practitioner removes the cap 64 from the finger flange 38 of the outer barrel 12, such as by sliding the cap 64 away from the finger flange 38, as shown in FIG. Figure 2C As shown by arrow A3 in FIG. 6 . Once the cap 64 is removed, the inner cylinder 14 is free to move further within the outer cylinder 12. With the inner cylinder 14 free to move to its furthest position within the outer cylinder 12, at step 124, the practitioner applies distal pressure (such as Figure 2C As shown by arrow D in FIG. 1 ), the pierceable portion 32 of the inner cylinder 14 contacts the protrusions 24 of the outer cylinder 12 and is pierced by these protrusions.

[0091] Once the inner barrel 14 is pierced, the practitioner continues to push the plunger rod 44 in the distal direction (as indicated by arrow D) at step 126 to move the stopper 42 through the inner barrel 14. The movement of the stopper 42 through the inner barrel 14 allows the second fluid F2 (such as flushing solution) in the inner barrel 14 to flow through the channel 72 in the protrusion 24 to the outer barrel 12. The second fluid F2 then passes through the outer barrel 12 and is discharged from the outer barrel 12 through the fluid port 20 to the VAD, as shown in FIG. Figure 2C As shown by arrow A4 in FIG. Figure 2D , the syringe 10 is shown in an end-of-use or final position, wherein the pierced inner barrel 14 is positioned completely against the inner surface of the distal end 18 of the outer barrel 12 , and both the first fluid F1 and the second fluid F2 are expelled from the syringe 10 .

[0092] Multi-barrel syringe including a stopper mounted to an inner barrel

[0093] Figure 4A and Figure 4B An additional example of a multi-barrel syringe 210 is shown for sequentially delivering a first fluid F1 (such as a medical fluid) followed by a second fluid F2 (such as a flushing solution). The syringe 210 includes Figures 1A to 3C Many of these components and features of the syringe 10 are shown. In particular, the syringe 210 includes an outer barrel 212, an inner barrel 214 inserted into the outer barrel 212, and a plunger ( Figure 4A and Figure 4B (not shown). The syringe 210 is Figures 1A to 3C The syringe 10 shown in the figure is operated in the same manner. In particular, when the pierceable portion 232 of the inner barrel 214 is intact, the practitioner can grasp and pull or push the plunger to move the inner barrel 214 through the outer barrel 212. Once the pierceable portion 232 of the inner barrel 214 is pierced by the protrusion of the outer barrel 212, applying distal pressure to the plunger causes the plunger to move through the inner barrel 214 to expel the second fluid F2 from the inner barrel 214 into the outer barrel 212 through the pierceable portion 232.

[0094] Figure 4A and Figure 4B The syringe 210 is different from the above examples in that Figures 1A to 3C The flange on the distal end of the inner cylinder shown is replaced by a seal or stopper 250 located on the closed distal end 228 of the inner cylinder 214. The seal or stopper 250 can include many features of conventional syringe stops or plungers known in the art. For example, the seal or stopper 250 can be formed by a thermoplastic elastomer material (such as polypropylene or polyethylene) and by a synthetic or natural rubber (e.g., isoprene). The seal or stopper 250 can include a proximal surface 252 or proximal end that contacts the closed distal end 228 and contacts the outer surface of the sidewall 230 of the inner cylinder 214. The stopper 250 also includes a distal surface 254 or distal end opposite to the proximal surface 252. In some examples, the distal surface 254 or distal end of the stopper 250 can be conical or truncated conical to facilitate the discharge of the first fluid F1 from the outer cylinder 212. Alternatively, the distal surface 254 or distal end of the stopper 250 may be substantially flat. The stopper 250 may also include an annular sealing surface 256 configured to seal against the inner surface of the sidewall 220 of the outer cylinder 212 to ensure that the first fluid F1 moves through the outer cylinder 212 in an intended manner.

[0095] In some examples, such as Figure 4A As shown, the stopper 250 is a full stopper that covers the distal end 228 of the inner cylinder 214. The sealing surface 256 of the stopper 250 extends around the periphery of the closed distal end 228 of the inner cylinder 214 and contacts the outer surface of the side wall 230. Figure 4A As shown, the stopper 250 covers the pierceable portion 232 of the inner cylinder 214. Therefore, the protrusion ( Figure 4A and Figure 4B (not shown) must be based on Figures 1A to 3CIn particular, when the protrusions are used with a full stopper 250, the protrusions must be sharp enough to pierce the elastic material of the stopper 250. In addition, the protrusions must be long enough to protrude into the interior of the inner cylinder 214 through the stopper 250 and the pierceable portion 232 of the inner cylinder 214.

[0096] In some examples, such as Figure 4B As shown, the stopper may be an annular stopper or a partial stopper 250. The annular stopper or the partial stopper 250 partially covers the distal end 228 of the inner cylinder 214 and extends around the periphery of the distal end 228 to contact some portion of the outer surface of the side wall 230 of the inner cylinder 214. In particular, in the case of the partial stopper or the annular stopper 250, the pierceable portion 232 of the inner cylinder 214 is not covered by the stopper 250. Therefore, the protrusion of the outer cylinder 212 does not need to be as in Figure 4A The elastic material of the stopper 250 is pierced as would occur in the case of the full stopper 250 shown. Figure 4B In the case of a partial stopper or annular stopper 250 , the protrusion of the outer cylinder 212 must still be long enough to protrude through the pierceable portion 232 of the inner cylinder 214 , taking into account the thickness of the stopper 250 .

[0097] Although examples of the multi-barrel syringe and method of the present disclosure are shown in the drawings and described in detail above, other examples will be apparent to and readily made by those skilled in the art without departing from the scope and spirit of the invention. Therefore, the foregoing description is intended to be illustrative rather than limiting. The invention described above is defined by the appended claims, and all changes to the invention that fall within the equivalent meaning and range of the claims will be included within the scope of the claims.

Claims

1. A multi-barrel syringe for sequentially discharging at least a first fluid and subsequently a second fluid, the syringe comprising: an outer barrel configured to contain the first fluid, the outer barrel comprising an open proximal end, a distal end comprising a fluid port, a sidewall extending between the proximal end and the distal end, and at least one protrusion extending from an inner surface of the outer barrel into an interior of the outer barrel; an inner cylinder configured to contain the second fluid, the inner cylinder being slidably insertable into the outer cylinder, the inner cylinder comprising an open proximal end, a closed distal end, and a sidewall extending between the proximal end and the distal end, wherein moving the inner cylinder through the outer cylinder causes the pierceable portion of the inner cylinder to contact the at least one protrusion of the outer cylinder to pierce the inner cylinder, thereby allowing the second fluid to flow from the inner cylinder to the outer cylinder; as well as A plunger is at least partially inserted into the inner barrel, the plunger being used to move the inner barrel through the outer barrel and to move through the inner barrel to expel the second fluid from the inner barrel through the pierceable portion of the inner barrel.

2. The syringe according to claim 1, wherein: When the pierceable portion of the inner barrel is intact, applying pressure to the plunger causes the inner barrel to move through the outer barrel.

3. The syringe according to claim 1, wherein: When the pierceable portion of the inner barrel is intact, applying proximal pressure to the plunger moves the inner barrel proximally through the outer barrel to draw the first fluid into the outer barrel through the fluid port.

4. The syringe according to claim 1, wherein: When the pierceable portion of the inner barrel is intact, applying distal pressure to the plunger moves the inner barrel distally through the outer barrel to expel the first fluid from the outer barrel through the fluid port.

5. The syringe according to claim 1, wherein: After the pierceable portion of the inner barrel is pierced by the at least one protrusion, applying distal pressure to the plunger causes the plunger to move through the inner barrel.

6. The syringe according to claim 1, wherein: The distal end of the inner cylinder includes an annular flange configured to contact an inner surface of the outer cylinder.

7. The syringe according to claim 1, wherein: The inner cylinder includes a stopper mounted to the distal end of the inner cylinder, the stopper being sized to seal against an inner surface of the sidewall of the outer cylinder.

8. The syringe according to claim 7, wherein: The stopper includes a full stopper covering the distal end of the inner cylinder and a portion of the side wall of the inner cylinder.

9. The syringe according to claim 7, wherein: The stopper includes an annular partial stopper partially covering the distal end of the inner cylinder.

10. The syringe according to claim 1, wherein: The pierceable portion of the inner barrel includes a recess in the closed distal end of the inner barrel.

11. The syringe according to claim 1, wherein: The plunger includes a stopper slidably positioned in the inner barrel and a plunger rod connected to and extending proximally from the stopper.

12. The syringe according to claim 1, wherein: The at least one protrusion includes at least one of a spike, a needle, a ridge, a point, a prong, or a post.

13. The syringe according to claim 1, wherein: The at least one protrusion is integral with the remainder of the outer cylinder.

14. The syringe according to claim 13, wherein: The outer barrel includes a plurality of protrusions extending inwardly from the distal end of the outer barrel.

15. The syringe according to claim 1, wherein: The at least one protrusion comprises at least one channel for fluid to flow from the inner barrel to the outer barrel after the pierceable portion of the inner barrel is pierced.

16. The syringe according to claim 15, wherein The at least one channel includes at least one of a groove, notch, opening, slot, cutout, cavity, or lumen extending at least partially through the at least one protrusion.

17. The syringe of claim 1, further comprising a removable cap engaged to the outer barrel and / or the inner barrel, the removable cap being configured to prevent the inner barrel from being fully inserted into the outer barrel when the cap is engaged.

18. The syringe according to claim 17, wherein The removable cap, when coupled to the inner barrel and / or the outer barrel, prevents the pierceable portion of the inner barrel from contacting and being pierced by the at least one protrusion of the outer barrel.

19. A pre-filled flushing syringe, the pre-filled flushing syringe include: The syringe of claim 1, wherein the inner barrel is at least partially inserted into the outer barrel, and the plunger is at least partially inserted into the inner barrel; as well as A predetermined volume of the second fluid is located in the inner cylinder, the second fluid being sealed in the inner cylinder by the plunger.

20. A method for sequentially expelling fluid from a syringe according to claim 1, the method comprising: applying distal pressure to the plunger to move the inner barrel through the outer barrel to expel the first fluid from the outer barrel through the fluid port; as well as Once the pierceable portion of the inner barrel is pierced by the at least one protrusion of the outer barrel, distal pressure is continued to be applied to the plunger to move the plunger through the inner barrel, thereby expelling the second fluid from the inner barrel into the outer barrel and out through the fluid port.

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