Patent Publication Number: US-2021162122-A1

Title: Medical devices for agent delivery and related methods of use

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims the benefit under 35 U.S.C. § 119 to U.S. Provisional Patent Application No. 62/943,060, filed on Dec. 3, 2019, the entirety of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to medical systems and devices for delivering pressurized fluids/agents, and more particularly, to methods and tools for controlling delivery of the fluid/agent at an appropriate pressure and flow rate. 
     BACKGROUND 
     In certain medical procedures, it may be necessary to stop or minimize bleeding internal to the body. For example, an endoscopic medical procedure may require hemostasis of bleeding tissue within the gastrointestinal tract, for example in the esophagus, stomach, or intestines. 
     During an endoscopic procedure, a user inserts a sheath of an endoscope into a body lumen of a patient. The user utilizes a handle of the endoscope to control the endoscope during the procedure. Tools are passed through a working channel of the endoscope via, for example, a port in the handle, to deliver treatment at the procedure site near a distal end of the endoscope. The procedure site is remote from the operator. 
     To achieve hemostasis at the remote site, a hemostatic agent may be delivered by a device inserted into the working channel of the endoscope. Agent delivery may be achieved through mechanical systems, for example. Such systems, however, may require numerous steps or actuations to achieve delivery, may not achieve a desired rate of agent delivery or a desired dosage of agent, may result in the agent clogging portions of the delivery device, may result in inconsistent dosing of agent, or may not result in the agent reaching the treatment site deep within the GI tract. The current disclosure may solve one or more of these issues or other issues in the art. 
     SUMMARY OF THE DISCLOSURE 
     Examples of the present disclosure relate to, among other things, agent delivery devices. Each of the examples disclosed herein may include one or more of the features described in connection with the disclosed examples. 
     A device may be configured to deliver an agent to a target tissue via pressurized fluid and the device may include a catheter including a lumen; an enclosure configured to store an agent, receive a pressurized fluid, and release a combination of the pressurized fluid and the agent; and a valve downstream of the enclosure to receive the combination of the pressurized fluid and the agent from the enclosure. The valve may have a first configuration preventing flow of the combination through the lumen and a second configuration permitting flow of the combination through the lumen. 
     Any of the systems and devices disclosed herein may have any of the following features. A first fluid input may be configured to release pressurized fluid from a pressurized fluid container into the lumen upon coupling the container to the first fluid input. The valve may be within a housing, and the housing may include a handle. The agent may be a powdered medicament. The valve may include a chamber, and the chamber may be fluidically connected to the lumen via an output channel. The valve may also include a rod including a plunger at a distal end of the rod, and the rod may extend through the chamber and may be configured to prevent fluid flow to the output channel in a first configuration and to allow fluid flow to the output channel in a second configuration. The valve may further include a slider slidably coupled to the chamber and including a slot, and the rod may extend through the slot, and the slider may be configured to transition the valve from a first configuration to a second configuration by movement of the slider. The valve may also include a biasing member coupled to the rod, and the biasing member may be configured to bias the rod towards the first configuration of the valve. The slider may include a slide on which the rod rests, the slide having a first portion including a curved surface and a second portion including a planar surface. The rod may include an end extending radially outward relative to an adjacent portion of the rod, and wherein the end of the rod prevents the rod from moving through the slot when the end of the rod contacts the slider. The end of the rod may slidably engage the slider. 
     The valve may include a chamber, and the chamber may be fluidically connected to the lumen via an output channel. The valve may also include a rod including a plunger at a first end of the rod and a cam-engaging surface at a second end of the rod, wherein the rod extends through the chamber and is configured to prevent fluid flow to the output channel in the first configuration and to allow fluid flow to output channel in the second configuration. The valve may further include a cam engaging the cam-engaging surface; a pinion fixedly coupled to the cam and comprising a first plurality of gears; a rack comprising a second plurality of gears, wherein the second plurality of gears are configured to mate with the first plurality of gears; and a biasing member coupled to the rod, wherein the biasing member is configured to bias the rod towards the first configuration of the valve. The cam may be pear shaped, the rod may be U-shaped, and the cam-engaging surface may include a wheel. A trigger may be coupled to the rack, wherein actuation of the trigger moves the rod to transition the valve from the first configuration to the second configuration. Movement of the rack in a first direction may be configured to move the pinion and the cam to transition the cam from a first position in which a central longitudinal axis of the cam is substantially parallel to a central longitudinal axis of the rack to a second position in which the central longitudinal axis of the cam is transverse to the central longitudinal axis of the rack; and movement of the rack in a second direction may be configured to move the pinion and the cam from the second position to the first position. The valve may include a chamber, wherein the chamber includes a distal opening fluidically connecting an interior portion of the chamber to the output channel; and a butterfly valve positioned within the distal opening. The butterfly valve may be configured to prevent fluid flow to the output channel in the first configuration of the valve and to allow fluid flow to the output channel in the second configuration of the valve, and rotation of the butterfly valve may move the butterfly valve to transition the valve from the first configuration to the second configuration. 
     The lumen may be a first lumen and the valve may include a chamber, wherein the chamber includes a distal opening fluidically connecting an interior portion of the chamber to the output channel; and a ball valve positioned within the distal opening and including a second lumen extend through the ball valve. The ball valve may be configured to prevent fluid flow to the output channel in the first configuration of the valve and to allow fluid flow through the second lumen to the output channel in the second configuration of the valve, and rotation of ball valve may transition the ball valve from the first configuration to the second configuration. A housing may include a handle, wherein the handle includes an interior portion configured to receive a fluid container. 
     A delivery device may be configured to deliver an agent to a target tissue via pressurized fluid. The delivery device may include: a catheter including a lumen, a proximal end, and a distal end; a enclosure configured to store an agent, receive a pressurized fluid, and release a combination of the pressurized fluid and the agent; and a first fluid input upstream of the enclosure. The first fluid input may be configured to release pressurized fluid from a pressurized fluid container toward the enclosure upon coupling the container to the first fluid input. In some examples, the pressurized fluid and agent may flow from the enclosure to the distal end of catheter upon coupling the container to the first fluid input. A total volume of pressurized fluid within the container may be configured to deploy a first amount of the agent through the distal end of the catheter. 
     In other examples, a method for controlling a fluid delivery to a body of a patient is disclosed. The method may include fluidically connecting a enclosure to a catheter, wherein the enclosure includes an agent within an interior portion of the enclosure and is configured to feed the agent into a lumen of the catheter; moving a distal end of the catheter to a target tissue site, the catheter including a lumen extending longitudinally through the catheter, and wherein the lumen is configured to receive a pressurized fluid from a container through a first input at a position proximally of the enclosure; coupling the container to the first input, wherein the container releases pressurized fluid stored within the container into the first input upon coupling the container to the first input; and contacting an actuator of a valve to open a fluid pathway from the first input to a distal opening of the lumen, causing a fluid and the agent to be released out of the distal end of the catheter. In some examples, the method may further include compressing a spring within the valve assembly; and breaking a fluid seal between an input channel and an output channel of the valve, wherein breaking the fluid seal fluidically connects the first input with the distal opening of the lumen. 
     It may be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. As used herein, the terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Throughout the drawings, the term “exemplary” is used in the sense of “example,” rather than “ideal.” The term “distal” refers to a direction away from an operator, and the term “proximal” refers to a direction toward an operator. The term “approximately,” or like terms (e.g., “substantially”), includes values+/−10% of a stated value. The term “distal” refers to a portion farthest away from a user when introducing a device into a patient. By contrast, the term “proximal” refers to a portion closest to the user when placing the device into the patient. Proximal and distal directions are labeled with arrows marked “P” and “D”, respectively, throughout the figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various exemplary embodiments and together with the description, serve to explain the principles of the disclosed embodiments. 
         FIG. 1  is a side view of a delivery system according to an exemplary embodiment. 
         FIG. 2  is a side view of a delivery system according to an exemplary embodiment. 
         FIGS. 3A and 3B  are cross-sectional views of a valve assembly in first and second configurations, respectively, according to an exemplary embodiment. 
         FIGS. 4A and 4B  are top views of a valve assembly in first and second configurations, respectively, according to an exemplary embodiment. 
         FIGS. 5A and 5B  are cross-sectional views of a valve assembly in first and second configurations, respectively, according to an exemplary embodiment. 
         FIGS. 6A and 6B  are cross-sectional views of a valve assembly in first and second configurations, respectively, according to an exemplary embodiment. 
         FIGS. 7A and 7B  are cross-sectional views of a valve assembly in first and second configurations, respectively, according to an exemplary embodiment. 
         FIG. 8  is a cross-sectional side view of a handle assembly including a valve assembly, according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An agent delivery device may be configured to house an agent at a distal portion of the delivery device and may be configured to control a rate at which an agent and a fluid leave the delivery device at a single location. The delivery device may be configured to house single component agents or multi-component agents. In the case of multi-component agents, the delivery device may be configured to allow for mixing of the components, prior to delivery from the device. Various mechanisms may be utilized in order to pre-pressurize a chamber of the agent and actuate the delivery device to deliver the agent while limiting the number of valves required in the device. These mechanisms may include pneumatics, wires, tubes, valves, or any suitable combination thereof. 
     Referring to  FIG. 1 , a delivery system  100  according to an embodiment is shown. Delivery system  100  may include a catheter  102 , a enclosure  104  containing an agent  112 , an enclosure adapter  105 , a fluid container  106 , a regulator  107  including a fluid source input  109 , and a filter  110 . In some examples, fluid container  106  may release pressurized fluid into regulator  107  when coupled to regulator  107 . For example, input port  109  may be configured to pierce fluid container  106  when fluid container  106  is coupled to regulator  107 , releasing pressurized fluid into regulator  107 . 
     With reference to  FIG. 1 , fluid container  106  is configured to contain a fluid, such as a gas, e.g., carbon dioxide or any other gas or other fluid known in the art. While shown as a cylinder, fluid container  106  may be any shape, such as a torpedo-shape, a sphere, or any other shape known in the art and used for storing fluid. For example, fluid container  106  could be a carbon dioxide tank or cylinder typically found in medical settings, such as a hospital, or a smaller, portable cartridge. In some examples, fluid container  106  may be fluidically connected to a fluid source separate from delivery system  100 , such as via a fluid catheter that may fluidically connect to a stationary fluid source in an operating room. Fluid container  106  may include one or more outer walls defining one or more inner chambers (not shown), the inner chamber(s) configured to contain the fluid. The walls of fluid container  106  may be formed of any material suitable for containing the fluid, such as but not limited to a metal alloy, a ceramic, or other material known in the art. The fluid contained in the inner chamber of fluid container  106  may be under pressure. Accordingly, the walls are formed of a material and/or a thickness suitable to contain the fluid at a pressure of, for example, at least approximately 1000 pounds per square inch (PSI), or approximately 850 PSI. For example, gases which may be contained in fluid container  106  may include carbon dioxide (CO2) having a vapor pressure of approximately 2,000-8,000 kPa at typical device temperatures, or nitrogen (N2) having a vapor pressure less than 40 MPa at typical device temperatures. It will be understood that these gases are examples and are not limiting to the types of gases contained in fluid container  106 . 
     With continued reference to  FIG. 1 , fluid container  106  is attached to regulator  107  at regulator input opening  109 . Regulator  107  includes a body  108  (including an input opening  109  and an output opening  111 , each for communication to external environment). Input opening  109  of regulator  107  may be configured to pierce fluid container  106 . Output opening  111  may be configured to fluidically couple to a proximal end of catheter  102 . Body  108  of regulator  107  may be any material known in the art, including but not limited to a metal alloy, a ceramic, and/or a resin. Regulator  107  may be configured to change to flow rate of fluid exiting fluid container  106  such that fluid enters a distal portion of catheter  102  at a selected flow rate. In some examples, fluid may enter a distal portion of catheter  102  at a flow rate in the inclusive range of approximately four standard liters per minute to twelve standard liters per minute of fluid flow. In some examples, delivery system  100  may be configured to operate with fluid flowing through a distal portion of catheter  102  at a flow rate in the inclusive range of between approximately five standard liters per minute to ten standard liters per minute. Fluid container  106  may be coupled to regulator  107  via a pull-cord coupling mechanism or a pump mechanism. In some examples, a pull-cord coupling mechanism may be included in system  100  and may include an actuator including a cord and a pin, and the pin may engage a carbon dioxide cartridge (or other fluid cartridge) to release fluid from the cartridge when a user pulls the cord. For example, the pin may puncture the cartridge and result in pressurized fluid flowing in system  100 . In other examples, a pump mechanism may be included in system  100  and may be configured to supply pressurized fluid to system  100 , for example by supplying pressurized gas in system  100 . In some examples, system  100  may not include regulator  107  and container  106  may be coupled directed to catheter  102  via an input opening similar to input opening  109 . 
     A distal portion of catheter  102  (a portion distal to regulator  107 ) may supply fluid under pressure from fluid container  106  and regulator  107  to enclosure  104  and enclosure adapter  105 . Enclosure  104  may be cylindrical and may include an interior cavity  118  and a funnel portion  119  at an end of enclosure  104 . Enclosure  104  may be configured to store an agent  112 , such as a powder or liquid medicament, within interior cavity  118  and interior cavity  118 , may be fluidically connected to adapter  105 . Funnel portion  119  may include tapered surfaces forming a portion of interior cavity  118  that lead to an opening  123  at an end of enclosure  104 . Funnel portion  119  may be configured to direct agent  112  through opening  123  into adapter  105 . In some examples, enclosure  104  may be configured to gravity feed agent  112  into adapter  105 . Enclosure  103  may be any suitable material known in the art. In some examples, enclosure  103  may be made of a transparent material. 
     Opening portion  123  may be configured to couple to adapter  105 . Adapter  105  may include an interior cavity (not shown) fluidically connecting three separate openings. Two of the three separate openings may be configured to couple to portions of catheter  102 , and one of the three separate openings may be configured to couple to opening  123  of enclosure  104 . An opening of adapter  105  may be configured to removably couple to enclosure  104 . Adapter  105  may be made of metal, polymer, or any other suitable material known in the art. 
     Catheter  102  may be cylindrical and may include a lumen extending along its central longitudinal axis. In some examples, catheter  102  may include a proximal portion  122  and a distal portion  121 . Proximal portion  122  of catheter  102  may be coupled to adapter  105  and may fluidically connect regulator  107  with adapter  105 . Distal portion  121  of catheter  102  may be coupled to adapter  105  at a proximal end of distal portion  121 , and distal portion  121  may extend to a distal opening  115 . Catheter  102  may be made of any material, for example reinforced rubber or a suitable plastic, that allows catheter  102  to withstand the pressures of the fluid, while simultaneously allowing for unrestricted movement of catheter  102 . Distal portion  121  may be flexible and be configured to bend to facilitate movement through a body lumen of a patient, e.g. a gastrointestinal tract. Proximal portion  122  of catheter  102  may include a filter  110  positioned within the lumen of catheter  102 . Filter  110  may be configured to allow fluid flow from the regulator  107  distally through the lumen of catheter  102 , and may also be configured to prevent movement of agent  112  proximally through catheter  102 . In some examples, filter  110  may be configured to restrict fluid flow through catheter  102  by narrowing the diameter of the interior lumen of catheter  102 . System  100  may provide a means to deliver agent  112  to a target tissue without the need of any valves within catheter  102 , which may reduce procedure time and may simplify a procedure of delivery of an agent  112  to tissue. 
     In operation, a user may first insert an agent  112  into enclosure  104  of delivery system  100 . The user may then position distal opening  115  of catheter  102  proximate to target tissue of a patient, for example target tissue within a body lumen of a patient. Once distal opening  115  is positioned proximate to or at the target tissue, the user may couple fluid container  106  to regulator  107 . By coupling fluid container  106  to regulator  107 , input port  109  may pierce or otherwise initiate fluid flow from fluid container  106  through regulator  107  and into catheter  102 . Fluid may then flow from regulator  107  through proximal portion  122  of catheter  102  and into adapter  105  and enclosure  104 . When fluid flows into adapter  105  and enclosure  104 , agent  112  may be moved in the direction of fluid flow and carried through catheter  102  to distal opening  115 . Agent  112  may then be deployed through distal opening  115  and propelled towards the target tissue via the fluid flow. Since the fluid flow is initiated when fluid container  106  is coupled to regulator  108 , a user does not need to actuate a valve or otherwise adjust the deployment of agent via fluid flow from fluid container  106 . The actuation of system  100  through coupling fluid container  106  to regulator  107  (for example, piercing a carbon dioxide container by coupling it to regulator  107 ) provides a means to deliver agent  112  to target tissue without the need for valving and produces a single shot of agent  112  to target tissue. For example, system  100  may be configured to receive a single shot of pressurized fluid supplied by fluid container  106 , such as a specific volume of carbon dioxide released from fluid container  106  in order to deliver a specific amount of agent  112  to distal opening  115 . By providing the user with a device that may deliver a measured amount of agent by connecting a fluid container  106  with a specific amount of fluid, additional steps of actuating a valve assembly or selectively releasing liquid into a device via an actuator may be eliminated, and may save the user time during an operation. In some examples, system  100  may not include regulator  107 . In some examples, all of or the majority of agent  112  may be moved out of enclosure  104  when fluid container  106  is coupled to regulator  108 , e.g., each enclosure  104  may be a single dosage of a therapeutic agent. The volume of fluid enclosure  106  may be configured to deploy a selected amount of agent  112  using system  100 . 
       FIG. 2  shows an alternative embodiment of a delivery system  200  substantially similar to delivery system  100 . Delivery system  200  may include catheter  202  including distal portion  222 , proximal portion  223 , and distal opening  215 ; adapter  205 ; fluid container  206 ; regulator  207  including regulator body  208 , regulator input opening  209  and output opening  211 ; enclosure  204 ; agent  212 ; and filter  210 . Any of the features described herein above regarding delivery system  100  may be included in delivery system  200 . Delivery system  200  may also include a valve  220  at a distal portion of catheter  202 , e.g. any portion of catheter  202  distal of adapter  205 . Valve  220  may be fluidically connected to an interior lumen of catheter  202 . In some examples, valve  220  may be coupled to distal portion  222  of catheter  202  and a distalmost portion  221  of catheter  202 . In other examples, valve  220  may be just distal of adapter  205 . 
     In operation, a user may first couple fluid container  206  to regulator  207  to pressurize delivery system  200  with pressurized fluid, such as pressurized carbon dioxide. Delivery system  200  may be configured to withstand cylinder pressure with valve  220  keeping the fluid pressure and agent  212  contained within delivery system  200 . Once delivery system  200  has been pressurized with fluid by coupling fluid container  206  to regulator  207 , the user may then selectively release the pressurized fluid and agent  212  from delivery system  200  by actuating valve  220 . In some examples, actuation of valve  220  may result in release of fluid and/or agent  212  through distalmost portion  221  of catheter  202  and out of distal opening  215 . By providing valve  220  at a distal portion of catheter  202 , a user may selectively delivery agent  212  to a target tissue and may allow the user to deliver agent  212  multiple times to the same target area or different target areas. Valve  220  may have any number of mechanisms for regulating the release of fluid from delivery system  200  which are discussed herein below. 
       FIGS. 3A and 3B  show cross-sectional views of an exemplary valve assembly  300 . Valve assembly  300  may be used as valve  220  in  FIG. 2 . Valve assembly  300  may be configured to operate under a constant fluid pressure feed into input channel  351 . Valve assembly  300  may include a valve chamber  323 , an input channel  351  including input lumen  350 , an output channel  353  including output lumen  352 , a rod  325  including a plunger  327  at a distal end of rod  325 , a biasing member  331 , and a slide  321 . Valve assembly  300  may be contained within a holding apparatus (not shown) that may be any suitable shape. For example, valve assembly  300  may be incorporated into a handle for a user to hold during operation (shown in  FIG. 8 ). 
     Chamber  323  may be cylindrical and may include a cover portion  333  at a proximal end of chamber  323  and a distal opening  390  fluidically connecting chamber  323  with output channel  353 . Chamber  323  may include a tapered distal portion  358  with a conical interior surface  359  tapering towards a central longitudinal axis of chamber  323  and towards distal opening  390 . Input channel  351  may be cylindrical and may fluidically connect to chamber  323  at an opening  354  at a proximal portion of chamber  323 . In some examples, distal portion  222  of catheter  202  (shown in  FIG. 2 ) may be fluidically coupled to input channel  351 , and distalmost portion  221  of catheter  202  (shown in  FIG. 2 ) may be fluidically coupled to output channel  353 . Input channel  351  may be positioned above output channel  353  to facilitate fluid flow (such as by allowing gravity to exert force onto the fluid to push the fluid towards output channel  353 ) from input channel  351  through chamber  323  to output channel  353 . 
     Rod  325  may be cylindrical and may extend through chamber  323 . In some examples, rod  325  may extend along a central longitudinal axis of chamber  323 . Plunger  327  may be coupled to a distal end of rod  325 . Plunger  327  may be conical and may extend radially-outward from a central longitudinal axis of rod  325 . In some examples, rod  325  may be tapered such that the distance between a central longitudinal axis of rod  325  and the radially-outer surface of plunger decreases as plunger  327  extends distally. Plunger  327  may be rubber, hard plastic, or any other suitable material known in the art. Plunger  327  may be configured to form a fluid-tight seal with chamber  323  at distal opening  390 . In some examples, rod  325  may be configured to translate distally within chamber  323  until plunger  327  contacts an interior surface of chamber  323  and forms a fluid tight seal preventing fluid from flowing through distal opening  390 . Proximal end  329  of rod  325  may be tapered and may extend radially outward from a central longitudinal axis of rod  325  as proximal end  329  extends proximally. Rod  325  may extend through an opening  371  (shown in  FIGS. 4A and 4B ) in slider  321  and also through an opening in cover  333 . Proximal end  329  of rod  325  may be tapered so as to prevent rod  325  from moving through opening  371 . Rod  325  may move proximally (up in the Figures) through opening  371 , such as when proximal end  329  is translated along a proximally-facing surface  355 ,  357  of slider  321 . 
     Biasing member  331  may extend circumferentially around rod  325  and may be coupled to cover  333  via a coupler  337 . Coupler  337  may fixedly couple a proximal end of biasing member  331  to cover  333 . A distal end of biasing member  331  may be fixedly coupled to plunger  327  and may contact a proximal-facing surface  361  of plunger  327 . In some examples, biasing member  331  may be a spring. Rod  325  may extend through a central longitudinal axis of biasing member  331 . Biasing member  331  may exert a force on rod  325  pushing rod  325  towards distal opening  390 . In an extended state (shown in  FIG. 3A ), biasing member  331  may exert a force on rod  325  such that plunger  327  forms a fluid tight seal with an interior surface of chamber  323 , preventing fluid flow through distal opening  390 . In a retracted state (shown in  FIG. 3B ), biasing member  331  may exert a force on rod  325  pushing rod distally towards distal opening  390 . Proximal end  329  of rod  325  may contact slider  321  and counteract the force exerted on rod  325  from biasing member  331 . In some examples, when a user transitions proximal end  329  from a position contacting first portion  355  of slider  321  to a position contacting second portion  357  of slider  321 , proximal end  329  may slide across second portion  357 , and rod  325  may move distally towards distal opening  390  via a force exerted on rod  325  from biasing member  331 . 
     Slider  321  may extend across cover  333  and across a proximal portion of chamber  323 . Slider  321  may be rectangular or any other suitable geometric shape. A proximal facing surface of slider  321  may include a first portion  355  and a second portion  357 . In some examples, first portion  355  may be planar and second portion  357  may be curved. Slider  321  may vary in thickness with a larger thickness at a portion of slider  321  including the first portion  355  and a smaller thickness at a portion of slider  321  including a second portion  357 . For example, slider  321  may extend outward from a central longitudinal axis of slider  321  as slider  321  extends from the second portion  357  to the first portion  355 . A distal facing surface  376  of slider  321  may be planar and may be configured to slide across cover  333  and/or a proximal end of chamber  323 .  FIGS. 4A and 4B  are top views of valve assembly  300  showing chamber  323 , cover  333 , proximal end  329  of rod  325 , and slider  321  including opening  371 .  FIG. 4A  corresponds to the position of valve assembly  300  shown in  FIG. 3A , and  FIG. 4B  corresponds to the position of valve assembly  300  shown in  FIG. 3B . Slider  321  may be designed with a slope of second portion  357  such that when slider  321  is translated from a position in which proximal end  329  moves from a position contacting first portion  355  to a position contacting second portion  357 , biasing member  331  returns rod  325  to a closed position, which may facilitate dosing of agent  339 . 
     Slider  321  is configured to translate transverse to the central longitudinal axis of rod  325  and is configured to move rod  325  in a proximal direction or a distal direction (up or down in the Figures). As slider  321  moves in a direction transverse to the longitudinal axis of rod  325 , proximal end  329  slideably engages proximal facing surfaces  355 ,  357  of slider  321 . For example, a user may transition valve assembly  300  from a first state shown in  FIGS. 3A and 4A  to a second state shown in  FIGS. 3B and 4B  by translating slider across cover  333  such that proximal end  329  slides across second portion  357  to first portion  355 , and thus forcing rod  325  to move proximally via the interaction between proximal end  329  and proximally facing surfaces  355 ,  357  of slider  321 . In some examples, slider  321  may include a flange  373  extending radially outward from a longitudinal axis of slider  321 . Flange  373  may be configured to prevent movement of slider  321  across cover  333  once flange  373  engages an exterior surface of chamber  323 .  FIG. 3B  shows an example of a position of valve assembly  300  in which flange  373  engages an exterior surface of chamber  323 . Slider  321  may be configured to couple to an actuator to facilitate movement of slider  321  to actuate valve assembly  300 . For example, slider  321  may be coupled to a trigger assembly (such as a trigger similar to trigger  574  shown in  FIGS. 5A, 5B, and 8 ). 
     In operation, a user may operate valve assembly  300  while operating delivery system  200 , with valve assembly  300  serving as valve  220  shown in  FIG. 2 . Once a fluid container  206  is coupled to input  209  and supplies pressurized fluid to delivery system  200 , a user may actuate valve assembly  300  to selectively release agent  339  through valve assembly  300 . For example, a user may translate slider  321  in a first direction to transition valve assembly from a closed state (shown in  FIG. 3A ) to an open state (shown in  FIG. 3B ) to release agent  339  through output channel  353  to be delivered to target tissue of a patient. Agent  339  may be moved from container  204 , through catheter  202 , and into valve assembly  300 , and output through output channel  353  for delivery to distal opening  215 . Agent  339  may be moved by a force applied to agent  339  via pressurized fluid supplied by fluid container  206 . To stop the release of agent  339  through output channel  353 , a user may translate slider  321  in a second direction opposite the first direction to move proximal end  329  from a position contacting first portion  355  of a proximally-facing surface of slider  321  to a position contacting second portion  357  of a proximally-facing surface of slider  321 , thus allow biasing member  331  to move rod  325  distally and move plunger  327  into a position fluidically sealing distal opening  390 . Once plunger  327  is at a position fluidically sealing distal opening  390 , fluid flow (shown as arrow  341 ,  343  and  345  in  FIGS. 3A and 3B ) is prevented from reaching output channel  353 . In some examples, the user may transition slider  321  from the position shown in  FIG. 4B  to the position shown in  FIG. 4A  to stop the release of agent  339  from output channel  353 . 
       FIGS. 5A and 5B  show an alternative embodiment of a valve assembly  500  that utilizes a cam and follower mechanism to actuate the valve assembly  500 . Valve assembly  500  may be used as valve  220  in  FIG. 2 . In some examples, valve assembly  500  may be configured to operate under a constant fluid pressure feed into an input channel  551 . Valve assembly  500  may include a valve chamber  523 , an input channel  551  including input lumen  550 , an output channel  553  including output lumen  552 , a rod  525  including a plunger  527  at a distal end of rod  525 , a biasing member  531 , a cover  533 , and a coupler  537 . Any of the components of valve assembly  500  may have any of the attributes and/or characteristics of components of valve assembly  300 . Valve assembly  500  may be contained within a holding apparatus (not shown) that may be any suitable shape. For example, valve assembly  500  may be incorporated into a handle for a user to hold during operation (shown in  FIG. 8 ). 
     Rod  525  may include a first portion  526 , a second portion  528 , a third portion  530 , and a wheel  560  at a distal end of third portion  530 . Each of first portion  526 , second portion  528 , and third portion  530  may be rigid and cylindrical or any other suitable shape. In some examples, wheel  560  may be rotatable relative to third portion  530 . In other examples, wheel  560  may be fixedly coupled to third portion  530 , may be configured to slidably engage cam  571 , and may not rotate. Although third portion  530  and input channel  551  are both shown in cross-section, third portion  530  is in a different plane than input channel  551  such that third portion  530  and input channel  551  do not intersect, but extend transverse to each other. First portion  526  may extend from plunger  527 , through an opening in cover  533 , to a position proximal to cover  533 . First portion  526  may be fixedly coupled to second portion  528 , and, in some examples, second portion may extend transverse to first portion  526 . In some examples, second portion  528  may have a central longitudinal axis perpendicular to a central longitudinal axis of first portion  526  and/or a central longitudinal axis of third portion  530 . Second portion  528  may be fixedly coupled to third portion  530  at a first end, and may be fixedly coupled to first portion  526  at a second end opposing the first end. Third portion  530  may extend distally from a first end to a second end, with the second end of third portion  530  coupled to wheel  560 . In some examples, a central longitudinal axis of third portion  530  may be parallel to a central longitudinal axis of first portion  526 . In some examples, first portion  526 , second portion  528 , and third portion  530  may form a U-shape. Third portion  530  may be held by a bracket  559  coupled to a housing (not shown) containing valve assembly  500 . Bracket  559  may allow proximal and distal movement of third portion  530 , and may prevent lateral movement transverse to the proximal and distal directions. In some examples, bracket  559  may be integrally formed with and/or fixedly coupled to housing  840  (shown in  FIG. 8 ). 
     Cam  571  may be fixedly coupled to a pinion  572 . Cam  571  may be pear shaped (shown in  FIGS. 5A and 5B ), snail shaped, circular with a pinion coupled at an off-center position, or any other suitable shape, and may be made of any suitable material known in the art. Pinion  572  may be cylindrical, and may be rotatably coupled to a housing (not shown) containing valve assembly  500 . Pinion  572  may include gears (teeth)  579 , and rotation of pinion  572  may result in rotation of cam  571 . Gears  579  may be configured to mate with gears (teeth)  573  of rack  570 . Rack  570  may be coupled to an actuator for translating rack  570  to move gears  573 , such as trigger  574  shown in  FIGS. 5A and 5B . Alternatively, rack  570  could be actuated via a button, lever, electronically controlled motor, or any other means known in the art. In some examples, movement of rack  570  via actuation of trigger  574  may engage gears  573  with gears  579 , and thus may cause rotation of pinion  572  and cam  571 . A central longitudinal axis of rack  570  may extend transverse to an axis of rotation of pinion  572 . In some examples, rotation of pinion  572  via rack  570  may transition cam  571  from a position in which a central longitudinal axis of cam  571  is transverse to a central longitudinal axis of third portion  530  ( FIG. 5A ) to a position in which a central longitudinal axis of cam  571  is aligned with a central longitudinal axis of third portion  530  ( FIG. 5B ). 
     In operation, a user may actuate rack  570  in order to open valve assembly  500  and release agent  539  to a distal opening  215  of catheter  202  (shown in  FIG. 2 ). After fluid container  206  is coupled to regulator  207 , pressurized fluid may flow into input channel  551  and chamber  523 . In a closed configuration (shown in  FIG. 5B ), plunger  527  prevents fluid flow through distal opening  590 . To open valve assembly  500 , the user may actuate rack  570 , for example by pushing on trigger  574 . By pushing on trigger  574 , gears  573  of rack  570  may engage gears  590  of pinion  572 , rotating pinion  572  and cam  571 . As cam  571  rotates, wheel  560  engages the exterior surface of cam  571 , and cam  571  pushes rod  525  proximally. By pushing rod  525  proximally, plunger  527  disengages with the interior surface of chamber  523  and allows fluid to flow through distal opening  590 . When the user releases trigger  574 , biasing member  531  may move rod  525  distally and return valve assembly  500  to a closed position ( FIG. 5B ). 
       FIGS. 6A and 6B  show an alternative embodiment of a valve assembly  600 . Valve assembly  600  may be used as valve  220  in  FIG. 2 . Valve assembly  600  may include a valve chamber  623  including interior portion  635 , an input channel  651  including input lumen  650 , an output channel  653  including output lumen  652 , a cover  633 , and a butterfly valve  601 . Any of the components of valve assembly  600  may have any of the attributes and/or characteristics of components of valve assemblies  300  and  500 . Valve assembly  600  may be contained within a holding apparatus (not shown) that may be any suitable shape. For example, valve assembly  600  may be incorporated into a handle for a user to hold during operation (shown in  FIG. 8 ). In some examples, valve assembly  600  may be configured to operate under a constant fluid pressure feed into input channel  651 . 
     Input channel  651  may extend through an opening in cover  633  and within chamber  623 . For example, a distal portion  624  of input channel  651  may extend along a central longitudinal axis of chamber  623  and a distal end  692  of input channel  651  may, in some examples, be positioned directly above (proximal to) distal opening  690 . Butterfly valve  601  may be oval shaped, or may be any other suitable shape. Butterfly valve  601  may be configured to extend across distal opening  690  so as to prevent fluid flow (shown as arrows  641 ,  642  in  FIG. 6A ) through distal opening  690  and into lumen  652  of output channel  653 . Butterfly valve  601  may include a pivot rod  602 , and butterfly valve  601  may pivot about pivot rod  602 . In some examples, pivot rod  602  may be configured to be actuated by a user by rotating pivot rod  602  to move butterfly valve  601 . In other examples, valve assembly  600 , and in some embodiments a butterfly valve  601 , may be actuated via a trigger rack and pinion, by gas flow, by a manual twist action, or a by pneumatic liquid/gas system. In some examples, actuating valve assembly  600  to transition valve assembly  600  from a closed to an open configuration may require rotation of butterfly valve  601  ninety degrees.  FIG. 6A  shows valve assembly  600  in a closed configuration in which fluid flow, illustrated by arrows  641 ,  642 , flows into chamber  623  but is prevented from flowing into lumen  652  of output channel  653 . When valve assembly  600  is in a closed configuration as shown in  FIG. 6A , butterfly valve  601  spans across distal opening  690  and seals distal opening  690 , preventing fluid flow into output channel  653 . In a closed configuration, a longitudinal axis of butterfly valve  601  may extend across distal opening  690 . When valve assembly  600  is in an open configuration as shown in  FIG. 6B , butterfly valve  601  is positioned to allow fluid flow through distal opening  690 , and thus allow agent  639  to flow through output channel  653 , illustrated by arrows  643 ,  644 ,  695 . For example, in an open configuration, a longitudinal axis of butterfly valve  601  may align with a longitudinal axis or distal portion  624  or a longitudinal axis of chamber  623 . A user may rotate pivot rod  602  to transition valve assembly  600  from a closed configuration to an open configuration, and vice versa. 
       FIGS. 7A and 7B  show another alternative embodiment of a valve assembly  700 . Valve assembly  700  may be used as valve  220  in  FIG. 2 . Valve assembly  700  may include a valve chamber  723 , an input channel  751  including input lumen  750  and distal end  792 , an output channel  753  including output lumen  752 , a cover  733 , and a ball valve  711 . Any of the components of valve assembly  700  may have any of the attributes and/or characteristics of components of valve assemblies  300 ,  500 , and  600 . Valve assembly  700  may be contained within a holding apparatus (not shown) that may be any suitable shape. For example, valve assembly  700  may be incorporated into a handle for a user to hold during operation (shown in  FIG. 8 ). In some examples, valve assembly  700  may be configured to operate under a constant fluid pressure feed into input channel  751 . 
     Ball valve  711  may be configured to extend across distal opening  712  so as to prevent fluid flow (shown as arrow  741 ,  742  in  FIG. 7A ) through distal opening  712  and into lumen  752  of output channel  753 . Ball valve  711  may be spherical and may include a lumen  713  extending through ball valve  711 . In some examples, ball valve  711  may include a pivot rod (not shown), and ball valve  711  may pivot about pivot rod. In some examples, actuation of a pivot rod may rotate ball valve  711 .  FIG. 7A  shows valve assembly  700  in a closed configuration in which fluid flow, illustrated by arrows  741 ,  742 , flows into chamber  723  but is prevented from flowing into lumen  752  of output channel  753 . When valve assembly  700  is in a closed configuration as shown in  FIG. 7A , ball valve  711  spans across distal opening  712  and seals distal opening  712 , preventing fluid flow into output channel  753 . In a closed configuration, a longitudinal axis of lumen  713  may extend across distal opening  712 , and an interior surface of chamber  723  may cover each end of lumen  713 . When valve assembly  700  is in an open configuration as shown in  FIG. 7B , ball valve  711  is positioned to allow fluid flow, illustrated by arrows  743 ,  744 ,  745 , through lumen  713  and distal opening  712 , and thus allow agent  739  to flow through output channel  753 . For example, in an open configuration, a longitudinal axis of lumen  713  may align with a longitudinal axis of distal portion  724  of input channel  751  or a longitudinal axis of chamber  723 . A user may rotate ball valve  711  to transition valve assembly  700  from a closed configuration to an open configuration, and vice versa. In some examples, actuating valve assembly  700  to transition valve assembly  700  from a closed to an open configuration may require rotation of ball valve  711  ninety degrees. Valve assembly  700 , and in some embodiments a ball valve  711 , may be actuated via a trigger rack and pinion, by gas flow, by a manual twist action, a by pneumatic liquid/gas system, or by any other method known in the art. 
       FIG. 8  shows a side cross-sectional view of an exemplary housing  840  containing valve assembly  500 . Housing  840  may include a handle portion  850  configured for a user to hold housing  840 . In some examples, handle portion  850  may be configured to enclose a regulator  851  and/or a fluid container  852 . A user may access an interior portion of handle portion  850  via a cap  853  removably coupled to a portion of handle portion  850 . A trigger  574  may extend outward from housing  840  to allow a user to actuate trigger  574 . Pressurized fluid may flow (shown as arrows  860 ,  861 ) from fluid container  852 , through regulator  851 , and into valve assembly  500 . Any of the valve assemblies  300 ,  500 ,  600 ,  700  disclosed herein may be incorporated into housing  840 . By providing a handle portion  850 , housing  840  may facilitate the use of valve assembly  300 ,  500 ,  600 ,  700  and provide a more ergonomic way for a user to hold and actuate a valve assembly  300 ,  500 ,  600 ,  700 . 
     Unless described otherwise, the structural elements of valve assemblies  300 ,  500 ,  600 ,  700  may be any material known in the art, including but not limited to a metal alloy, a ceramic, and/or a resin. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed device without departing from the scope of the disclosure. Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.