Intraocular gas injector

Abstract

To provide an intraocular gas injector.SOLUTION: A gas mixing apparatus includes a measurement and control system, an activation system, a pressurized chamber having one or more gases, and a mixing chamber. A filter may be pre-attached to the outlet of the mixing apparatus to allow excess gas to be exhausted through the filter and then ambient air to be drawn into the mixing apparatus through the filter to produce a therapeutic gas mixture.SELECTED DRAWING: Figure 2A

Description

Technical Field

[0001] The present invention disclosed herein generally relates to devices and methods for injecting gas into an animal's eye.

Background Art

[0002] In surgical procedures, injection of gas or other fluids into a target area may be required for the treatment of certain injuries, disorders, and diseases. In the treatment of eye conditions such as macular holes, retinal tears, and detachments, part of the surgical procedure may involve injection of gas or other fluids into the eye.

[0003] For example, retinal detachment is an eye disease involving the separation of the retina from the retinal pigment epithelium (RPE), which is the tissue that holds the retina in place. Retinal detachment can occur due to inflammation caused by a retinal tear, traction on the retina, or fluid accumulation in the subretinal space, which causes the retina to begin separating from the RPE tissue. This disease can also be caused by posterior vitreous detachment (PVD), proliferative diabetic retinopathy (PDR), injury, or neovascularization of fibrous or vascular tissue that detaches the retina from the RPE. Such conditions, if not treated immediately, can lead to partial vision loss and possibly further blindness.

[0004] Treatment methods for uncomplicated retinal detachment may include non-surgical techniques such as pneumatic retinopexy, laser photocoagulation, or cryopexy. More complicated retinal detachments require surgical intervention. In some cases, due to the risk of infection that can cause blindness, such surgeries are performed under aseptic conditions to significantly reduce the possibility of infection. Surgical methods include vitrectomy, which is the removal of the vitreous humor; in the case of traction retinal detachment, dissection and removal of the membrane; and in the case of additional retinal tears, photocoagulation or cryopexy. Following such surgical procedures, intraocular gas tamponade may be used. Intraocular gas tamponade can keep the retinal tissue in contact with the RPE and keep the retina attached during the healing process after the surgical procedure.

[0005] During the healing process, since the intraocular pressure must be maintained relatively constant, the gas selected usually expands at a constant pressure (isobaric process). Therefore, the intraocular gas tamponade can be a bubble of air mixed with an expansible gas such as sulfur hexafluoride (SF6), hexafluoroethane (C2F6), or octafluoropropane (C3F8). The intraocular gas tamponade dissolves over time depending on the gas and concentration used. For example, sulfur hexafluoride, when mixed with air at a concentration of about 20 percent, dissolves within 1 to 2 weeks, hexafluoroethane, when mixed with air at a concentration of about 16 percent, dissolves in about 4 to 5 weeks, and octafluoropropane, when mixed with air at a concentration of about 12%, dissolves in about 6 to 8 weeks. Changing the concentration of these gases affects the time required.

[0006] Current techniques involve the use of gases contained within a plurality of separate pressurized containers for multiple doses. These gases are then mixed with air and transferred to a syringe for injection into a patient's eye. Thus, during the surgical procedure, multiple non-sterile and sterile steps are required to fill the syringe with the desired concentration of gas and air. These non-sterile and sterile steps are typically performed by non-sterile peri-operative nurses and sterile instrument pushers who support the surgeon within the sterile field. During the first non-sterile step, the peri-operative nurse prepares a non-sterile reusable gas container by setting the pressure regulator connected to the gas container to the appropriate pressure. During the second step, the instrument pusher prepares a sterile syringe by connecting a stopcock, filter, and tubing in series onto the syringe. During the third step, the tubing is connected to the gas container. The instrument pusher carefully passes the free end of the sterile tubing through a non-visible sterile barrier to the waiting non-sterile peri-operative nurse. The non-sterile peri-operative nurse receives the tubing and carefully ensures that neither the instrument pusher nor any other sterile surface is contaminated as the tubing is connected to the regulator on the gas container. During the fourth step, the syringe is then filled with gas from the container. The instrument pusher and the peri-operative nurse coordinate the opening of the pressurized container valve to release gas through the connected tubing, filter, and stopcock into the syringe. The pressure of the released gas is sufficient to push the syringe plunger along the length of the syringe barrel, thereby filling the syringe with gas. The instrument pusher ensures that the gas is not pushing the plunger out of the open end of the syringe barrel and signals the peri-operative nurse to close the gas container valve when the syringe approaches being completely filled. During the fifth step, the syringe is then purged to ensure that most of the air that may have been present within the syringe, stopcock, filter, and tubing before filling with gas is removed. The instrument pusher turns the stopcock to provide a means for releasing the air and gas within the syringe to the atmosphere and pushes the syringe plunger to empty all of its contents from the syringe. The instrument pusher then turns the stopcock in the opposite direction to return the connection path to the tubing and gas container.

[0007] Steps 4 and 5 are repeated several times to further reduce the amount of air initially present in the syringe, stopcock, filter, and tubing, flushing most of the air from the syringe, stopcock, filter, and tubing, and purging air from the system. During the 6th step, the syringe is then refilled with gas from the container. The surgical instrument removal specialist removes the tubing from the filter and signals to the circulating nurse to carefully take the tubing and remove it from the sterile area. During the 7th step, the surgical instrument removal specialist stops the plunger so that not all of the contents of the syringe are discharged and only the measured volume of gas remains in the syringe. For example, the gas can be discharged so that only 12 mL remains in the syringe. During the 8th step, the surgical instrument removal specialist replaces the used filter with a new sterile filter and draws filtered room air into the syringe until the total air / gas mixture in the syringe reaches the appropriate volume for the desired gas concentration.

[0008] For example, air can be drawn into the syringe so that the total volume of air and gas is 60 mL and thus a concentration of 20 percent is achieved. Since the pressurized container is non-sterile and the syringe and the surgical area are sterile, the completion of the above-described steps must be carried out by at least one person in the non-sterile area (usually the circulating nurse) and a second person in the sterile area (usually the surgical instrument removal specialist), requiring coordination and communication between the two people.

[0009] This procedure requires a complex series of steps and there is an increased risk of errors. An error in one of these steps can lead to the use of an incorrect concentration of gas, which may result in either a pressure increase or a decrease in the duration of retinal tamponade, thereby potentially causing ischemia or failure of the reduction procedure. Both of these can potentially cause blindness. Furthermore, current techniques generate a significant amount of wasted gas, are costly, and are harmful to the environment. Therefore, the handling of such gases in pressurized containers, especially those containing more than one dose, poses a potential danger to the operator if mishandled. Thus, in some countries, it may even be prohibited to store these pressurized containers in the operating room.

[0010] Although there are some techniques for improving current procedures, such as the container for a single dose that can be placed within a sterile area and the Alcon® Constellation® system that enables gas filling and purging described in U.S. Patent No. 6,866,142 (Lamborne et al.), these techniques are insufficient to address all potential issues. Another technique where a syringe device includes an internal pressurized cannister of an expandable gas within a volume limiting mechanism is disclosed in U.S. Patent No. 8,986,242. In use, the volume limiting mechanism is set to the volume of the expandable gas corresponding to the final desired concentration of the gas tamponade, which may include the expandable gas and air. The expandable gas is released into the syringe chamber until the plunger of the syringe hits the volume limiting mechanism structure, and the remaining expandable gas is vented to the atmosphere. Subsequently, a filter is attached to the outlet of the syringe mechanism, and air is drawn into the syringe chamber through the filter to create a mixture of the desired concentration of expandable gas and air for later injection. SUMMARY OF THE INVENTION MEANS FOR SOLVING THE PROBLEM

[0011] At least one aspect of the invention disclosed herein includes the recognition that an intraocular gas injector device can be assembled and packaged in a manner that reduces or eliminates the operations required of the user and can further reduce potential sources of contamination. For example, as described above with respect to the use of the device disclosed in U.S. Patent No. 8,986,242, an expansible gas is supplied to an internal mixing chamber of a syringe device and some excess expansible gas is discharged through the outlet of the syringe. Thereafter, a filter is attached to the outlet of the syringe and air is drawn through the filter into the mixing chamber.

[0012] At least one aspect of the invention disclosed herein includes the recognition that an intraocular gas injection device can include a syringe body, a source of therapeutic gas, and a filter pre-attached to the syringe outlet, for example, prior to the expulsion of excess therapeutic gas through the outlet. In some embodiments, the gas injection device with the pre-attached filter can be packaged in a sterile container for use in a surgical procedure. Thus, a user can open the sterile container, remove the intraocular gas injection device, and operate the intraocular gas injection device with the filter in place throughout the gas mixing process. For example, with the filter pre-attached, a user can supply an expansive gas to the mixing chamber of the syringe to at least partially fill the mixing chamber with the expansive gas or another selected gas, and in some modes of use, enable the excess expansive gas to be expelled from the mixing chamber, through the outlet of the syringe body, through the filter, and then to the atmosphere. Such expulsion of excess expansive gas does not result in any well-known particular direct and beneficial effect. However, using the intraocular gas injector in such a mode with the filter in place during the expulsion of excess expansive gas results in a reduced risk of contamination of various space volumes within the device, including the space volume between the plunger of the syringe and the filter membrane of the filter device. Further, once the expulsion of excess expansive gas is complete, the user can then draw air into the mixing chamber through the filter without opening the intermediate space volume to the atmosphere. Thus, the intermediate space volume between the filter membrane and the plunger of the syringe remains closed to the atmosphere, and only air filtered through the filter device is received.

[0013] After the user draws in a desired amount of air and filters it through the filter device, the filter device can be removed and a desired instrument can be attached to the syringe outlet. For example, in some embodiments, the user can attach a needle for injecting a mixed inflation gas and air into the eye of an animal or patient for treating a detached retina. After attaching such a needle, the user can flush the needle with the mixed inflation gas and air in the mixing chamber. Thus, there is no volume of space exposed to unfiltered air between the filter membrane and the syringe plunger prior to surgical use.

[0014] At least one other aspect of the invention disclosed herein includes the recognition that filling a variable volume gas mixer with a metered source gas can lead to insufficient expansion of the variable volume chamber and thus failure to produce a mixed gas of the desired concentration. Thus, at least one aspect of the invention disclosed herein includes the recognition that providing a flow restriction device on the outlet of a filter attached to the outlet of an intraocular gas injection device can be beneficial to more reliably ensure that the mixing chamber expands to a desired volume of a therapeutic gas such as an inflation gas or a component of a therapeutic gas, and can provide beneficial and / or additional backpressure.

[0015] At least one other aspect of the invention disclosed herein includes the recognition that, after the mixing chamber is filled with the treatment gas, a flow restrictor attached to the outlet of the downstream filter of the intraocular gas injector can cause an unduly strong flow restriction during the process of drawing in ambient air or atmosphere through the filter. Thus, at least one aspect of the invention disclosed herein provides that providing a removable flow restrictor at the outlet of the filter of the intraocular gas injection device can provide two beneficial operating modes, generating a desired back pressure during the discharge of excess treatment gas during the filling stage of the mixing chamber, ensuring that the mixing chamber fully expands to the desired volume for containing the desired amount of treatment gas, and then, with the flow restrictor removed, the user can manually expand the mixing chamber and draw in the atmosphere through the filter, and the difficulties associated with such an operation do not increase when the flow restrictor is in a predetermined position. Thus, at least one aspect of the invention disclosed herein includes an intraocular gas injection device having a downstream filter device and a removable flow restrictor at the downstream end of the filter device.

[0016] At least one other aspect of the invention disclosed herein includes the recognition that when the filter device is attached to the outlet of the syringe in the operating room, foreign matter or contaminants can enter the upstream end of the filter device, and thus may be contained within the volume disposed between the filter membrane and the plunger. Thus, even if some excess expandable gas is subsequently discharged through the filter, such contaminants and / or foreign matter may be trapped by the filter membrane and then backflush into the mixing chamber when the atmosphere is drawn in reverse through the filter. Thus, at least one aspect of the invention disclosed herein includes a configuration and method of operation that reduce the possibility of contaminants and / or foreign matter entering the space volume disposed between the filter membrane and the plunger. BRIEF DESCRIPTION OF THE DRAWINGS

[0017]

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[0018] The following detailed description is merely illustrative in nature and is not intended to limit the embodiments of the present subject matter or the application and uses of such embodiments. As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any implementation described herein as illustrative is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.

[0019] In the following description, certain terms may be used for reference purposes only, and therefore are not intended to be limiting. For example, terms such as "upper", "lower", "upper" and "lower" refer to directions within the drawings to which reference is made. Terms such as "proximal", "distal", "front", "rear", "rear" and "side" describe the orientation and / or location of parts of a component within a consistent, but arbitrary, frame of reference that is made clear by reference to the text and associated drawings that describe the components being described. Such terms may include those specifically mentioned above, derivatives thereof and words of similar meaning. Similarly, the terms "first", "second" and other such numerical terms also refer to structures.

[0020] As used herein, the terms "front" and "distal" refer to the part of the device of the present subject matter that is farther from the user (e.g., the surgeon) of the device during the injection operation. As used herein, the terms "rear" and "proximal" refer to the part of the device that is closer to the user (e.g., the surgeon) of the device during the injection operation.

[0021] Device for mixing two gases Figure 1A shows one embodiment of a gas mixing kit 2 that may include a gas mixing device 10 enclosed within a container 4. The container 4 can be any type of container suitable for use in housing components of a surgical kit, use in a sterile internal environment, use in an operating room such as within a sterile area of an operating room, and use during a surgical procedure. In some such containers, a thermoformed plastic tray includes a structure for holding components including surgical components in a predetermined arrangement and a fragile seal made of a thin film material. In some embodiments, the surgical components including the gas mixing device 10 are sterilized and inserted into the container 4 within a sterile environment, and in some embodiments, an inert gas is enclosed within the container 4. Other types of containers can also be used.

[0022] The gas mixing device 10 can be configured to form a therapeutic gas or a component of a therapeutic gas. For example, the gas mixing device 10 can be configured to receive into a mixing chamber a therapeutic gas or a component of a therapeutic gas and, in some embodiments, a second gas that can be air in some embodiments, for later discharge for therapeutic use. For example, in some embodiments, the gas mixing device 10 can be used to create a therapeutic gas mixture for injection into a patient, in some embodiments, into the eye of a patient.

[0023] Continuing to refer to FIG. 1A, the gas mixing device 10 may include a mixing system 310, a pressure regulating system 710, and a filter device 760. The mixing system 310 may include an external housing 311, a therapeutic gas source 410, and a mixing chamber 510. The mixing chamber 510 may be defined by a portion of the housing 311 and a movable wall such as a plunger 460. The plunger 460 may be in the form of a plunger commonly provided within a syringe device.

[0024] The mixing system 310 may also include a pressure regulating system 610 disposed between the source 410 and the mixing chamber 510. The pressure regulating system 610 may include a valve. The valve is configured to hold the source 410 in a closed state and, when actuated, release the contents of the source 410 through the valve 610 into the mixing chamber 510.

[0025] The pressure regulating system 710 may be configured to control the flow of gas into and out of the mixing chamber 510. For example, the pressure regulating system 710 may be configured to allow excess gas originally from the source 410 supplied to the mixing chamber 510 to escape to the atmosphere. For example, the pressure regulating system 710 may be configured to controllably release gas from the mixing chamber 510 at a pressure above atmospheric pressure. Further, the pressure regulating system 710 may be configured to allow gas to enter the mixing chamber 510 when the pressure within the mixing chamber 510 is below atmospheric pressure.

[0026] The filter device 760 may include a filter membrane (not shown) or another filtering device configured to remove particles, foreign matter, or other substances from the gas flowing therethrough. The filter device 760 may include an outlet end 761 in communication with the atmosphere. The outlet 761 may be used to discharge gas from the mixing chamber 510 and to admit atmosphere for mixing within the mixing chamber 510 into the filter device 760. Optionally, the filter device 760 may further include a flow restrictor 1300. The flow restrictor 1300 is configured to restrict the flow exiting from and / or entering the outlet 761.

[0027] Kit 2 can be prepared in a sterile environment and can receive a gas mixing device 10 with or without any flow restrictor 1300 such that the filter member 760 is attached to the mixing device 310 and sealed within the container 4. In use, a physician can open the container 4 and release a therapeutic gas or gas component from the supply source 410 into the mixing chamber 510.

[0028] Introduction of gas into the mixing chamber 510 causes the plunger 460 to move to the left (as seen in FIG. 1A), thereby allowing the volume of the mixing chamber 510 to expand in accordance with the introduction of the therapeutic gas from the supply source 410 into the mixing chamber 510. For example, in some embodiments, the supply source 410 is a pressurized container of a therapeutic gas or a component of a therapeutic gas. Thus, when pressurized gas is released into the mixing chamber 510, the pressure within the mixing chamber 510 increases, thereby biasing and moving the plunger 460 and thereby expanding the volume of the mixing chamber 510.

[0029] The pressure adjustment system 710 may include a valve mechanism. The valve mechanism is configured to open when exposed to a pressure above atmospheric pressure and at the same time provides a flow restriction such that it causes the plunger 460 to move and creates a sufficient backpressure to expand the mixing chamber 510. When the plunger 460 has moved sufficiently to expand the mixing chamber 510 to the desired volume of the therapeutic gas, the pressure adjustment device system 710 vents the remaining excess gas from the supply source 410 and allows it to flow out through the filter device 760 and the outlet 761. Since all internal spaces within the device 10 were pre-sterilized and stored within the sterile environment of the container 4, it is considered that the upstream side of the filter device 760 does not capture any foreign matter or contaminants as the excess gas flows through the filter device 760. Thus, during the discharge of excess gas from the mixing chamber 510, the filter device 760 is not thought to perform any desired filtering function.

[0030] After chamber 510 is filled with the treatment gas or components of the treatment gas of the desired volume, plunger 460 can be manually moved, for example (as seen in Figure 1A), towards the left, into outlet 761, through filter device 760, through pressure adjustment system 710, and into mixing chamber 510 to draw in air. Thus, filter device 760 can capture foreign matter and / or other undesirable gases that may be present in the air and prevent these substances from entering mixing chamber 510.

[0031] Plunger 460 can be moved to a desired position corresponding to a mixture of gas from the desired source 410 and air. After the desired mixture is formed within mixing chamber 510, the user can remove filter 760 and attach a delivery device (not shown), such as a hypodermic needle, to pressure adjustment device 710 for further discharge.

[0032] For example, in connection with using device 10 for mixing an expansible gas from source 410 and air for the treatment of a detached retina, the user can attach a hypodermic needle to the illustrated position of filter device 760 downstream of pressure adjustment system 710. With the needle attached in this way, the user can manually move plunger 460 to the right (as seen in Figure 1A), flush the hypodermic needle with the contaminant-free mixed gas from within mixing chamber 510, and then continue the procedure of providing treatment to the patient, for example, by introducing bubbles of the mixed expansible gas and air from mixing chamber 510 into the patient's eye.

[0033] In some embodiments, as described above, device 10 may include a flow restrictor 1300. The flow restrictor 1300 can provide additional restriction to the flow entering and exiting the outlet 761. Thus, during the addition of the treatment gas to the mixing chamber 510, the flow restrictor 1300 can provide additional backpressure, thereby moving the plunger 460 (to the left), and thereby ensuring that sufficient positive pressure is generated within the mixing chamber 510 to fully expand the mixing chamber 510 to a desired volume related to the desired final concentration of the mixture within the mixing chamber 510.

[0034] Figure 1B shows a further embodiment of a gas mixing kit 2, generally designated by reference numeral 2a. Kit 2a includes a gas mixing device 10a housed within a container 4a. As described above with reference to container 4, container 4a can house system 10a in a sterile state for opening and use in a surgical environment. Gas mixing device 10a can include a measurement control system 110a, an activation system 210a, a mixing system 310a configured to create a mixture of two or more gases in a desired concentration ratio, and a pre-attached filter 760a. Further, optionally, kit 2a can include a removable flow restrictor 1300 attached to the outlet 761a of filter device 760a. Mixing system 310a can optionally also include a pressurization chamber 410a and a mixing chamber 510a.

[0035] Mixing system 310a can also include a pressure adjustment system for improving the operation of mixing system 310a. In some embodiments, mixing system 310a additionally includes a first pressure adjustment system 610a and a second pressure adjustment system 710a.

[0036] The measurement control system 110a can be in the form of a measurement mechanism housed within the mixing system 310a to control specific aspects of the devices housed within the hybrid system 310a. In some embodiments, the measurement control system 110a can be a variable and user-adjustable device. The activation system 210a can be operably coupled to the pressure chamber 410a to activate the operation of the device and initiate the mixing of gases within the mixing system 310a.

[0037] Any pressure chamber 410a can accommodate at least one of two or more gases to be mixed within the mixing system 310a. In some embodiments, the gas housed within the pressure chamber 410a can be at a pressure higher than the ambient environmental conditions. Further, the pressure chamber 410a can accommodate a gas at a concentration different from its concentration in the atmosphere. The pressure chamber 410a can be configured to be in fluid communication with a first pressure adjustment system 610a. In other embodiments, the pressure chamber 410a can be in direct fluid communication with the mixing chamber 510a. The pressure chamber 410a can be configured to be housed internally within an injector device. The pressure chamber 410a can also be configured to be external to the injector device. The first pressure adjustment system 610a can be configured to maintain a preset pressure difference between the pressure chamber 410a and the mixing chamber 510a.

[0038] The mixing chamber 510a can be configured to receive gas from the pressure chamber 410a either directly or via the first pressure adjustment system 610a. In some embodiments, the mixing chamber 510a can be additionally configured to receive a second gas to be mixed from outside the mixing system 310a, such as an external gas container or the atmosphere. The mixing chamber 510a can be configured to be in fluid communication with a second pressure adjustment system 710a at the outlet point of the mixing chamber 510a. In other embodiments, the mixing chamber 510a can be in direct fluid communication with the atmosphere at the outlet point of the mixing chamber. Examples of each of these subsystems will be described separately below.

[0039] In some embodiments, the measurement control system 110a is configured to control the concentration of the gas within the gas mixing device 10a. In some embodiments, the measurement control system 110a is operably coupled to the mixing system 310a. Preferably, the measurement control system 110a is operably coupled to either the pressurization chamber 410a or the mixing chamber 510a such that the measurement control system 110a can vary the aspect of the pressure chamber 410a and / or the mixing chamber 510a.

[0040] In some embodiments, the measurement control system 110a can control characteristics such as, but not limited to, the volume of gas contained within the mixing chamber 510a. Other characteristics such as pressure are also contemplated to be controllable by the measurement control system 110a. Preferably, the measurement control system 110a is variable such that a user can select the desired concentration ratio of the gas that can be released from the gas mixing device 10a. This advantageously enables the user to have only a single gas mixing device 10a for a wide range of desired concentration ratios. Thus, the measurement control system 110a can include a user-operable switch such as a dial that varies the operation of components within the mixing system 310a, such as the pressurization chamber 410a, the mixing chamber 510a, the first pressure adjustment system 610a, and the second pressure adjustment system 710a.

[0041] The pressurization chamber 410a can be configured to store one or more gases for a period of time within the internal space of the pressurization chamber 410a before mixing two or more gases within the gas mixing device 10a. The conditions within the internal space are configured to be different from those of atmospheric pressure conditions. Thus, the internal space should generally reduce the release of such gases from the internal space or reduce the entry of non-stored gases into the internal space until the mixing of two or more gases is performed.

[0042] In some embodiments, one or more gases within the internal space are at a pressure higher than ambient atmospheric pressure conditions. Further, the one or more gases can also be gases with a concentration different from the concentration at ambient atmospheric pressure conditions. In some embodiments, the internal space can be divided into separate subsections or portions for holding one or more gases. Thus, these separate portions of the internal space can be maintained at different gas pressures and / or different gas concentrations.

[0043] In some embodiments, the gas can additionally be disposed within different structural units within the internal space. Such structural units can be used to more effectively reduce the release of stored gas and / or more effectively reduce the entry of non-stored gas. In some embodiments, the stored gas in the pressurized chamber 410a is pre-loaded during manufacture. In other embodiments, it is contemplated that the contents of the pressurized chamber 410a can be loaded by the user of the gas mixing device 10a. For example, the stored gas can be housed within a removable cartridge-like device that can advantageously facilitate the exchange of such gases.

[0044] In some embodiments, the activation system 210a is configured to activate the operation of the gas mixing device 10a and initiate the process of mixing two or more gases within the mixing system 310a. Accordingly, the activation system 210a is operably coupled to the mixing system 310a and can be coupled to both the mixing chamber 310a and the pressurization chamber 410a. The activation system can activate the pressurization chamber 410a and discharge the gas contained within the pressurization chamber 410a into the mixing chamber 510a. In some preferred embodiments, the activation system 210a can cause an increase in the pressure within the pressurization chamber 410a such that a first pressure adjustment system 610a is activated, thereby enabling fluid to flow from the pressurization chamber 410a into the mixing chamber 510a. The activation system 210a can include a device configured to activate a separate portion of the pressurization chamber 410a that contains a higher pressure gas than the remainder of the pressurization chamber 410a such that the pressure within a separate section of the pressurization chamber 410a increases. In a preferred embodiment, the activation system 210a can open a sealed device within the mixing chamber 510a to release the pressurized gas, thereby discharging the pressure throughout the pressurization chamber 410a. In such an embodiment, the activation system 210a can include a piercing device that can create a hole in the seal. Other devices and techniques can also be used. The use of the activation system 210a provides the advantage of enabling the gas mixing device 10a to be optionally pre-filled and stored safely prior to use.

[0045] The activation system 210a can also be operably coupled to the mixing chamber 510a, enabling a user to manually vary certain aspects of the device. In some embodiments, the activation system 210a can be used to change the volume of the mixing chamber 510a. The activation system 510a can also be used to change the pressure of the mixing chamber 510a.

[0046] In some embodiments, the first pressure adjustment system 610a is configured to serve as a separation mechanism between the pressurization chamber 410a and the mixing chamber 610a. The first pressure adjustment system 610a can be activated when a preset pressure difference between both the pressurization chamber 410a and the mixing chamber 510a is reached. In some preferred embodiments, the first pressure adjustment system 610a may include at least one valve assembly. The valve assembly can open when the pressure within a portion of the pressurization chamber 410a is higher than the pressure within the mixing chamber 510a. The valve assembly can be a check valve, a flapper valve, a backflow prevention valve, or a one-way valve. Such valves can also include a ball check valve, a diaphragm check valve, a swing check valve, a screw-down check valve, a lift check valve, an in-line check valve, and a duckbill valve. Other pressure adjustment mechanisms can also be used. Furthermore, it is considered that the first pressure adjustment system 610a can also be activated by other means other than the pressure difference of the system 610a.

[0047] In some embodiments, the mixing chamber 510a is configured to function as a space where two or more gases can be mixed inside to obtain a desired concentration ratio of the gases. The mixing chamber 510a can be configured to have an adjustable variable volume when using the activation mechanism. The mixing chamber 510a can receive the gas to be mixed from only the pressurization chamber or from the gas already present within the mixing chamber 510a. The mixing chamber 510a can also receive gas from a secondary source. In some embodiments, the mixing chamber 510a can receive air from the atmosphere to mix with the gas received from the pressure chamber 310a and / or from the gas already present within the mixing chamber 510a.

[0048] In some embodiments, the second pressure regulating system 710a is configured to serve as a separation mechanism between both the mixing chamber 510a and the ambient atmosphere. The second pressure regulating system 710a can be activated when a preset pressure difference between both the mixing chamber 510a and the ambient atmosphere is reached. In some preferred embodiments, the second pressure regulating system 710a may include at least one valve assembly. The valve assembly can open when the pressure in the mixing chamber 510a is higher than the pressure of the ambient atmosphere. The valve assembly can be a check valve, a flap valve, a backflow prevention valve or a one-way valve. Such valves may also include a ball check valve, a diaphragm check valve, a swing check valve, a screw-down check valve, a lift check valve, an in-line check valve and a duckbill valve. Other pressure regulating mechanisms can also be used. Further, it is considered that the second pressure regulating system 710a can also be activated by other means than the pressure difference of the system 710a.

[0049] Kit 2a may also include a filter device 760a attached to the outlet of the mixing chamber 510a and / or the outlet of the second pressure regulating system 710a. The filter device 760a may include an external housing and an internal filtering component such as a membrane having a desired porosity or aperture size for filtering and removing unwanted foreign substances, materials and / or gases. The filter device 760a may include an outlet 761a in communication with the atmosphere. During the assembly of kit 2a, the mixing device 10a has components 110a, 210a, 310a, 410a, 510a, 610a, 710a and the filter device 760a attached in a sterile packaging chamber, sealed in a container 4a in a sterile state and optionally filled with a sterilized inert gas. Accordingly, the empty internal volumes within and between components 110a, 210a, 310a, 410a, 610a, 510a, 710a and 760a are all sterilized with an inert gas within the sealed package 410a and / or are either filled with an inert gas. Optionally, as described above, kit 210a may also include an additional flow restrictor 1300 attached to the outlet 761a of the filter device 760a.

[0050] Operation overview Referring to FIGS. 2A-2D, the operation of one embodiment of the gas mixing device 10b is shown. Referring to FIG. 2A, the device 10b may be in an initial stage where the activation system 210b is in the first or "closed" position and is housed within the package 4b. At this stage, the device 10b is in a fully sterilized state where all internal volumes, including the internal volume between the filter element of the filter device 760 and the plunger 460 (not shown), are filled with sterilized and / or sterilized inert gas.

[0051] A physician or other user can remove the device 10b from the package 4b and use the measurement control system 110b to select the desired concentration of the treatment gas to be mixed. Thereafter, the user can use the activation system 210b to release gas from the gas source 410b into the mixing chamber 510b.

[0052] For example, referring to FIG. 2B, the gas contained within the pressurized chamber 410b can be released, and in embodiments including a first pressure adjustment system, the first pressure adjustment system can open in response to a change in pressure within the chamber. Thus, fluid can flow from the pressurized chamber into the mixing chamber 510b, thereby causing an increase in the volume of the mixing chamber 510b. However, due to the components of the measurement control system 110b, the plunger 460b of the mixing chamber 510b stops at the first volume selected by the user and cannot expand beyond this first volume. This first volume can be set based on the desired concentration of the injectable volume. During this first operation stage, excess gas can also be released from the mixing chamber 510b via the second pressure adjustment system 710b. When the mixing chamber reaches this first volume, the first operation stage is complete and the second operation stage begins.

[0053] During the second operation phase, while the pressure in the mixing chamber 510b is being released from the system via the filter 760 and the second pressure regulation system 710b, the mixing chamber 510b can remain at the first volume. By overfilling the mixing chamber 510b with the desired gas and then releasing that gas, this substantially purges any amount of atmospheric or inert gas supplied to the container during packaging that may have been contained within the mixing chamber 510b prior to startup from the mixing chamber 510b and helps ensure that the gas originally contained within the pressurized chamber is displaced. When the pressure in the mixing chamber 510b reaches a setpoint based on the configuration of the second pressure regulation system 710b, the release of gas from the mixing chamber 510b stops and the second operation phase is complete.

[0054] During the third operation phase, as shown in FIG. 2C, after sufficient time has elapsed for the gas to reach atmospheric pressure, the user can then set the activation system 210b to the first or "closed" position, thereby unlocking the measurement control system 110b. The user can then manually expand the volume of the mixing chamber 510b to its fillable volume. When the user manually expands the volume of the mixing chamber 510, ambient air is drawn into the mixing chamber 510b through the filter device 760b. Thereby, the filter 760b can filter and remove foreign matter or gas from the ambient air before this air enters the chamber 510b.

[0055] Once the third stage is complete, referring to FIG. 2D, the filter device 760b can be removed and an additional device (not shown) configured to deliver the treatment gas within the mixing chamber 510b can be attached. For example, a hypodermic needle can be attached to the device 10b to support the therapeutic delivery of the treatment gas within the mixing chamber 510b to the patient. In some embodiments, the gas within the mixing chamber 510b can be a mixture of an expansible gas and filtered air for the treatment of a detached retina. In such a case, the hypodermic needle attached to the device can purge any gas that may be present within the hypodermic needle by pushing in a plunger through which 460b discharges a portion of the gas from the mixing chamber 510b through the hypodermic needle. Thereafter, the needle can be inserted into the patient's eye and the gas from the mixing chamber 510b can be used to generate one or more bubbles within the patient's eye for the treatment of the detached retina. Other uses are possible.

[0056] In other embodiments, fewer or more operational stages can be implemented. In some embodiments, only one operational stage can be implemented. For example, the pressurization chamber 410a can contain a gas at a preset concentration level. During one operational stage, the user can activate the device 10b such that gas or fluid flows from the pressurization chamber 410a to a second chamber such as the mixing chamber 510a until the chamber reaches a set volume. The gas or fluid can also be discharged or released using a pressure adjustment system until the desired pressure within the chamber is obtained. After the gas is discharged, the device 10b can be ready for use. As will be apparent to those skilled in the art, in such embodiments, in practice, mixing may hardly be implemented.

[0057] System Overview Referring to FIG. 3, the components of one embodiment of a gas mixing device 10b including a measurement control system 110b, a startup system 210b, a pressurization chamber 410b, a mixing chamber 510b, a first pressure adjustment system 610b, and a second pressure adjustment system 710b are shown. The measurement control system 110b may include a measurement dial 120 and a plunger body 160 that can be inserted into the measurement dial 120. The startup system 210b may include an operating rod 220 and a startup switch 260. The startup system 210b may be operably coupled to a measurement control device 110b for controlling the operation of the gas mixing device 10b. The startup system 210b may be inserted into the plunger body 160.

[0058] The pressurization chamber 410b may include a housing 420, a canister 436 for containing gas, a release mechanism 444 for releasing the gas contained within the canister 436, a filter 448 for reducing the amount of non-gas or bacterial substances flowing out of the housing 420, and a plunger seal 460. The mixing chamber 510b may include a syringe body 520. The first pressure adjustment system 610b may include a valve body and associated valve components. The second pressure adjustment system 710b may also include associated valve components.

[0059] Measurement control system and startup system Referring to FIG. 4, one embodiment of the combined measurement control system 110b and startup system 210b is shown. The measurement control system 110b may include a measurement dial 120 and a plunger body 160. The startup system may include an operating rod 220 (shown in FIG. 7) and a startup switch 260.

[0060] Referring to FIGS. 5A and 5B, an embodiment of a measurement dial 120 of a gas mixing device 10b is shown that is configured to allow a user of the device 10b to selectively vary the concentration of the injectable volume. The measurement dial 120 includes two structural components, a measurement body 122 and a measurement cap 124, and the measurement cap 124 can be coupled to the measurement body 122 to allow the measurement dial 120 to be removably attached to another component of the device 10b. Thereby, advantageously, the assembly of the device can be facilitated, and in some embodiments, a reusable device can be easily removed for resterilization. In some embodiments, the measurement cap 124 can be removably attached to the measurement body 122 using fasteners such as screws, rivets, clips, and other fastening mechanisms well known in the art. When the measurement cap 124 is attached to the measurement body 122, an annular slot 126 and an annular lip 128 can be formed so that the measurement dial 120 can be attached to another component of the device 10b. For example, the annular slot 126 and the annular lip 128 can correspond to a flange 526 located on the syringe body 520.

[0061] The measurement body 122 can have a substantially cylindrical member 130 having a flange 132 at its upper end and a channel 134 that is substantially centered in the cylindrical member 130 and extends throughout the meter body 122. Since the meter body 122 is configured to control the concentration of the gas within the injectable volume, the meter body 122 can include a measurement indicator 136 along a surface visible to the user of the device 10b in a fully assembled state. In the illustrated embodiment, the measurement indicator 136 is located on the top surface of the flange 132, but any location visible to the user can be used. The measurement indicator 136 can provide information regarding the operation of the device 10b to the user of the device. In the illustrated embodiment, the measurement indicator 136 indicates numbers in the ranges of 18, 19, 20, 21, and 22 corresponding to the concentration of sulfur hexafluoride (SF6) generated within the injectable volume when the device 10b is activated. As will be apparent to those skilled in the art, the ranges used can depend on the gas used and the application of the gas. Further, in some embodiments, this range can be further divided to provide enhanced control over the desired concentration.

[0062] The measurement body 122 can have slots 138 corresponding to the measurement indicator 136, the slots 138, and variable stops 142. In the illustrated embodiment, the measurement body 122 has five separate slots 138 corresponding to the five integer values described above, located along the inner surface of the channel 134. In other embodiments, the measurement body 122 can have fewer or more slots than the number of values provided by the measurement indicator 136.

[0063] Corresponding to each of these slots 138 is a variable stop 142 that extends inwardly from the slot 138. As described above, these variable stops 142 can be in the form of a surface extending from the top surface of the flange 132 having a lower end surface 142a disposed at a set distance from the lower end of the cylindrical body 130. In some embodiments, the variable stop 142 need not extend from the top surface and instead is a small protrusion having a lower end surface 142a disposed at a set distance toward the lower end of the cylindrical member 130. These variable stops 142 interact with components housed within the plunger body 160, such as the latch 228, or the plunger body 160 itself, and are configured to control the expansion volume of the mixing chamber 510b during the first and second operating phases by restricting the rearward extension of the plunger body 160 during these phases (see FIG. 2B). Thus, the variable stops 142 extend at different distances depending on the concentration to which the stop 142 corresponds. For example, at a concentration of 21 percent, it extends downward at a shorter distance than at a concentration of 20 percent, thereby enabling the mixing chamber 510b to hold a greater amount of the first gas. This is the end of the third operating phase (FIG. 2C) before filtered ambient air is added during the fourth phase (FIG. 2D). Thus, if a concentration of 21 percent is selected, the plunger body 160 can be extended rearward a greater distance, thereby enabling a greater expansion of the mixing chamber 510b during the first operating phase. Thus, as is apparent, the variable stops 142 are used to control the first expansion volume of the first operating phase.

[0064] On both sides of slot 138, there are slots 138 extending inwardly from the inner surface of channel 134. In some embodiments, slot 138 extends inwardly from the inner surface of channel 134 at a distance greater than variable stop 142. Slot 138 can be configured to prevent device 10b from switching to different concentration values once device 10b is activated. This can be particularly important in applications where a specific concentration of gas may be required and any slight change in this value could have extremely harmful effects. In the illustrated embodiment, slot 138 is configured to greatly reduce the possibility that plunger body 160 rotates to different variable stops 142 during at least the first two operating stages. In certain embodiments, if a constantly changing measurement device is desired, these rails can be removable. Instead, in such embodiments, variable stop 142 can have an inclined shape rather than having a plurality of steps.

[0065] Measurement body 122 can additionally include a ratchet pole 144 extending inwardly along the inner surface of channel 134 towards the center of channel 134. Ratchet pole 144 is hingedly connected and ratchet pole 144 can be configured to be movably deformable and provide resistance during deformation. This ratchet pole 144 can correspond to features located on plunger body 160 to encourage an appropriate orientation for the selected concentration. Such a mechanism can additionally provide the user of the device with a tactile feedback indicating that proper alignment has been obtained. This tactile feedback can advantageously reduce the likelihood of activation in an inappropriate orientation. Other types of feedback mechanisms and alignment mechanisms can also be used.

[0066] Referring to FIG. 6, an embodiment of the plunger body 160 is shown that includes a generally cylindrical frame 162, a handle 164 at one end of the plunger body 160, a selector ring 166 positioned between the generally cylindrical frame 162 and the handle 164, and a channel 168 that is centered within the cylindrical frame 162 and extends over the entire length of the plunger body 160. The cylindrical frame 162 is configured to be slidably translatable and partially rotatably slidable within the channel 134 of the measurement dial 120.

[0067] The cylindrical frame 162 has a retaining mechanism 170 in the form of a clip that is hingedly attached to the cylindrical frame 162. The retaining mechanism 170 can be configured to hold components such as the housing 420 of the pressure chamber 410b. The retaining mechanism 170 advantageously allows components to be attached without the use of tools, thereby facilitating the overall assembly process of the device. Further, the retaining mechanism 170 can also be configured such that components can be removed from the cylindrical frame 162. Thereby, enabling the reuse of the device 10b or, in other embodiments where the device 10b is reusable, facilitating the resterilization process when such a process is used on the device. Other types of retaining mechanisms may also be used instead of the clip shown in the illustrated embodiment and may include fasteners such as screws.

[0068] The cylindrical frame 162 may additionally include a guide 172 extending outwardly from the outer surface of the cylindrical frame 162. The guide 172 can extend from the lower end of the cylindrical frame 162 to a distance relative to the upper end of the cylindrical frame 162. The guide 172 is configured to be positioned along the inner surface of the channel 134 of the measurement body 122 and fit within the slot 138. Thus, the guide 172 can prevent the plunger body 160 from rotating when disposed between the slots 138. Thereby, after the start of the first operation stage, the plunger body 160 can be advantageously prevented from moving to different variable stops 142, thereby reducing the risk of an inappropriate concentration of the injectable volume. The guide 172 is preferably sized such that when the plunger body 160 is fully inserted, the guide 172 is only slightly below the slot 138 so that the plunger body 160 can freely rotate to different concentration values during the initial operation stage (see FIG. 2A). However, since the guide 172 is only slightly below the slot 138, the guide 172 can be locked into the selected rail 140 after extending a short distance. This positioning advantageously enables the guide 172 to lock shortly after the activation of the device 10b. Further, the guide 172 preferably extends outwardly from the cylindrical frame 162 by a distance sufficient to contact the slot 138 but not sufficient to contact the variable stop 142 positioned between the slots 138. Thus, this can prevent the guide 172 from being obstructed by the variable stop 142 during operation.

[0069] The cylindrical frame 162 can additionally include a latch aperture 174 configured to allow a latch 228 (FIG. 7) located on the activation rod 220 to project outwardly from the cylindrical frame 162. The latch aperture 174 is preferably disposed centrally directly above the uppermost portion of the guide 172. As described in detail below, in the first or “closed” position, the latch 228 is retracted so as not to extend beyond the guide 172 and thus does not contact the variable stop 142 (see FIG. 8A). When in the second position, the latch 228 extends outwardly beyond the guide 172 from the cylindrical frame 162 such that the latch can contact a variable stop 140 such as the lower surface 142a, thereby preventing further extension of the plunger body 160 while the latch is in the second position (see FIG. 8B). Thus, the volume by which the chamber 510b can expand is limited by the latch 228 and the surface 142a. In some embodiments, the latch aperture 174 is arranged such that if the plunger body 160 is misoriented within the measurement dial 120 during an initial operating phase (shown in FIG. 2A), the rail 140 of the measurement dial 120 can prevent the latch 228 from extending outwardly to the second or “open” position. This can advantageously prevent the device 10b from activating if misoriented.

[0070] The cylindrical frame 162 can additionally include a ratchet slot 176 in the form of a cutout located along its outer surface. The ratchet slot 176 is configured to receive the ratchet pole 144 of the measurement body 122, thereby providing a mechanism to ensure that the plunger body 160 is properly oriented within the measurement body 122 by providing resistance to rotation when the pole 144 is received within one of the ratchet slots 176. Further, advantageously, at each location where the ratchet pole 144 is received within the ratchet slot 176, the user of the device 10b can receive tactile feedback when the plunger body 160 is properly oriented within the measurement body 120.

[0071] Continuing to refer to FIG. 6, the selector ring 166 can include an annular protrusion extending from the outer surface of the cylindrical frame 162. The selector ring 166 can additionally include a selector indicator 178 that can take the form of a small protrusion located on the selector ring 166. The selector indicator 178 corresponds to and can be aligned with a measurement indicator 136 (FIG. 5A) located on the measurement body 122 to indicate the concentration level obtained when the plunger body 160 is oriented in its position corresponding to the alignment of the latch 228 with the corresponding surface 142a. Such a system can advantageously provide the user of the device with easily visible information regarding the selected concentration level. The selector indicator 178 can preferably be colored to facilitate the use of the device 10b.

[0072] The handle 164 can extend radially with respect to the longitudinal axis of the cylindrical frame 162. The handle 164 can be shaped such that a user of the device 10b can grip the handle 164 and use the handle to either further extend the plunger body 160 rearward and out of the device 10b or further push the plunger body 160 forward into the device 10b. The handle 164 can additionally include an aperture 180 for receiving a coupling mechanism of the activation switch 260. The activation switch 260 can thereby rotate about the coupling mechanism to operate an actuating rod 220 located within the plunger body 160.

[0073] Referring to FIG. 7, an embodiment of a starting system 210b including an actuating rod assembly 220 and a starting switch 260 is shown. The actuating rod assembly 220 has a generally elongated body having an actuator pin 222 at a first end, an actuator stem 224 at a second end, and a latch moving portion 226 located at an intermediate portion. When in the second or "open" position, the actuator pin 222 is received within the housing 420 of the pressure chamber 410b and is configured to initiate the release of gas contained within the housing 420.

[0074] The actuator stem 224 is configured to abut and follow a curved surface 262 (FIG. 9) of the starting portion switch 260. It is also preferred that the actuator stem 224 is shaped such that its cross-sectional outer shape matches the cross-sectional outer shape of the upper portion of a channel 169 located near the handle 164 of the plunger body 160 (as shown in FIG. 8). Preferably, the cross-sectional outer shape is not substantially circular such that rotation of the actuator rod 220 within the channel 168 of the plunger body 160 is substantially prevented. The latch moving portion 226 is shaped to translate the latch 228 when the latch 228 is slidably translated along the latch moving portion 226 of the actuating rod 220. Accordingly, the latch 228 has an aperture 230 having a cross-sectional shape similar to the cross-sectional shape of the latch moving portion 226.

[0075] The starting switch 260 is configured to translate the actuator rod 220 through a portion of the plunger body 160 and through the housing 420 of the pressure chamber 410b to initiate the release of the gas contained within the housing 420. Thus, the starting switch 260 may include a cam having a curved outer profile 262 along a surface configured to contact the actuator stem 224. The starting switch 260 may also have an aperture 264 configured to receive a pin 266 such that the starting switch 260 can rotate about the pin 266. In the illustrated embodiment, the starting switch 260 is shown in a first or "closed" position. In this first position, the distance between the pin 266 and the curved surface 262 in contact with the actuator stem may be a reduced distance such that the actuator rod remains in the first or "closed" position.

[0076] When rotated about the pin 266 to a second or "open" position, the distance between the pin 266 and the curved surface 262 in contact with the actuator stem 224 becomes an increased distance, thereby translating the actuator rod 220 further into the housing 420 of the pressure chamber 410b to the second or "open" position. As described in more detail below with respect to FIGS. 10 and 11, movement to the second or "open" position may be configured to release the gas within the pressure chamber 410b. The starting switch 260 may preferably be any type of switch that can remain in the first position or the second position without the user having to maintain the switch in that position. In the illustrated embodiment, a rotary lever is used. Other switches such as screws, latches, spring-loaded pins or any other switch well known in the art may also be used.

[0077] Referring to FIGS. 8A and 8B, a diagram of the operation of the activation system 210b including some components of the measurement control system 110b and the activation system 210b is shown. As shown here, the latch 228 is housed within the latch aperture 174 so that the latch cannot translate towards the front or rear end of the plunger body 160. Thus, when the actuator rod 220 translates in the forward or rearward direction, the latch 228 must follow the outer profile of the latch movement portion 226 of the actuator rod 220. Thus, this provides the advantage of the coupling movement of the latch 228 at the second position when the activation switch 260, and thus the actuator rod 220, is in the corresponding second position. Further, since the movement of the latch 228 is coupled with the movement of the other activation switches 260 and actuator rods 220, if the latch 228 is prevented from moving to the second position, the activation switch 260 and the activation rod 220 will also be prevented from moving to the second position. As described above, while in the second or "open" position, the latch 228 can project from the plunger body 160, and it should be noted that thereby, as shown in FIG. 8B, the extension of the plunger body 160 is restricted.

[0078] Pressurization Chamber and First Pressure Regulation System Referring to FIG. 9, an embodiment including some components of both the activation system 210b, the pressurization chamber 410b of the mixing system 310b, and the first pressure regulation system 610b of the mixing system 310b is shown. As shown, the pressurization chamber 410b can have a housing 420 having an annular slot 422 located near the first end of the housing 420. The annular slot 422 can be configured to receive the retaining mechanism 170 located on the plunger body 160. The housing 420 can also have a plunger seal 460 located at the second end of the housing 420. The plunger seal 460 is configured to provide an airtight seal that defines the mixing chamber 510b.

[0079] Refer to FIG. 10, which is a cross-sectional view of the pressurization chamber 410b and the first pressure adjustment system 610b. The annular slot 422 is located at the first or rear end, and the conical or frustoconical surface 424 located at the second or front end corresponds to the shape of the plunger seal 460. The housing 420 can be additionally shaped to have an annular protrusion 426 and an annular slot 428 configured to receive the lip 462 of the plunger seal 460. This configuration advantageously ensures that the plunger seal 460 remains connected to the housing 420, forms a seal, and prevents leakage of any gas contained within the housing body 420. The lip 462 of the plunger seal 460 fits tightly within the annular slot 428 of the housing 420 and can provide seal reinforcement.

[0080] The internal space 430 is substantially enclosed by the housing 420 and can be separated into a first distinct portion 432 and a second distinct portion 434. Contained within the second distinct portion 434 of the housing 420 can be a third distinct portion in the form of a structural unit such as a canister 436. This canister can contain gas for mixing in the mixing chamber 510b. Providing gas within the canister can be advantageous for facilitating the manufacture of the device 10b because it allows the canister to be manufactured separately from the other components of the pressurization chamber 410b. In some embodiments where the device 10b is reusable, the canister can be replaced.

[0081] The canister 436 has a first or rear end that contacts the actuator pin 222 and a sealed second or front end 437. At one end of the canister 436 is a seal 438 that substantially reduces any gas leakage from the first distinct portion 432 to the second distinct portion 434. This advantageously reduces the likelihood of gas leakage from the actuator aperture 440 and the device 10b.

[0082] The housing 420 may also include a biasing mechanism 442, such as a spring, that acts on the seal with a force in a direction away from the second end of the housing 420. In the illustrated embodiment, the biasing mechanism 442 is located within a first separate portion 432. Thereby, the canister 436 moves to the first separate portion 432, reducing the potential for the gas contained within the canister 436 to be released without being activated by the user. Further, the biasing mechanism 442 can provide a reaction force against activation so that the user cannot accidentally activate the device. The biasing mechanism 442 is configured to apply sufficient force such that after the first and second operating phases are completed and the activation switch 160 returns to its first or "closed" position, the actuator rod 220 returns to its first or "closed" position, thereby returning the latch 228 to its first or "closed" position. When the latch 228 returns to its first or "closed" position, the extension of the plunger body 160 is no longer restricted and the third operating phase can begin. If the biasing mechanism 442 does not apply sufficient force to the actuator rod 220, entering the third operating phase can become more difficult.

[0083] The housing 420 can also have a discharge mechanism 444, such as a needle or a pilot tip, as shown in the device 10b of this embodiment. The discharge mechanism 444 is configured to puncture the sealed second end 437 of the canister 436 and discharge gas through the discharge mechanism 444 to the first separate portion 432 via an axially extending channel 446 within the discharge mechanism 444. The high pressure within the first separate portion 432 can open the first pressure regulating system 610b, allowing gas to exit into the front of the plunger seal 460 and into the mixing chamber 510b. In some embodiments, a filter 448 can be disposed along the flow path to reduce the likelihood of foreign matter entering the mixing chamber 510b. In some embodiments, the filter 448 can be configured to filter out and remove bacteria.

[0084] The plunger seal 460 is configured to partially define the injectable volume of the mixing chamber 510b by creating a seal for the mixing chamber 510b. The plunger seal 460 may have a generally cylindrical body having an annular protrusion 464 configured to contact the inner surface of the mixing chamber 510b and a conical or frustoconical surface 466 at the front end. The frustoconical surface 466 may additionally include an aperture 468 configured to receive a component of the first pressure regulation system 610b, which is disposed in the center of the cylindrical body. Further, the body may also have an opening 470 defined by a lip 462 at the rear end and configured to receive the housing 420.

[0085] Continuing to refer to FIG. 10, an embodiment of the first or “closed” position of the first pressure regulation system 610b is shown. The first pressure regulation system 610b may include a valve body 620 including a plurality of apertures 622 at one end, a valve stem 624 extending into the valve body 620, the valve stem 624 having a valve seat 626 configured to contact a biasing mechanism 628 at the rear end, and a head 630 configured to contact a seal ring 632 at the front end.

[0086] During operation, the head 630 is biased against the seal ring 632 and the valve body 620, whereby the biasing mechanism 628 can apply a biasing force in a rearward direction against the valve seat 626 so as to reduce or prevent the flow of gas through the valve body 620 and ultimately into the mixing chamber 510b. Due to the orientation of the biasing mechanism 628, the first pressure regulation system 610b remains closed until the pressure in the pressurization chamber 410b exceeds a threshold value. This threshold value may be set by changing the amount of force required to compress the biasing mechanism 628.

[0087] Referring to FIG. 11, an embodiment of a first pressure regulating system 610b is shown in an "open" position where the pressure in the pressurization chamber 410b exceeds the pressure in the mixing chamber 510b. In some preferred embodiments, the pressure difference is significant. This pressure difference applies a force to the valve component sufficient to overcome the biasing mechanism 628, thereby allowing gas to flow out of the valve body 620 and into the mixing chamber 510b.

[0088] This configuration of the first pressure regulating system 610b is advantageous due to the multiple operating stages of the device 10b. During at least a portion of the first and second operating stages, the pressure difference keeps the valve open. However, when the pressure difference becomes insufficient to overcome the threshold, the valve remains in the closed position, preventing any additional gas from flowing into the mixing chamber and potentially disrupting the calculated pressure / concentration.

[0089] Referring to FIG. 12, an embodiment of a mixing chamber 510b is shown that includes a syringe body 520, a second pressure regulating system 710b, and various components of the system described above. The syringe body 520 can be a cylindrical body and can include an aperture 522 at the rear end and a threaded nozzle 524 at the front end. The syringe body also has a flange 526 configured to engage with the measuring device 120. The mixing chamber 510b can be defined by the inner wall of the syringe body 520 and the plunger seal 460. Further, the syringe body can include an indicator 528 corresponding to a selected concentration along its outer surface. These indicators 528 can advantageously provide the user with a visual confirmation of the selected concentration.

[0090] Referring to FIG. 13, an embodiment of a second pressure regulating system 710b is shown that includes a valve body 720 that can include a ball 722, a biasing mechanism 724, a valve seat 726, and a sealing mechanism 728. The second pressure regulating system 710b can also include a second biasing mechanism 730 and a pin actuator 732.

[0091] The valve body 720 may be translatable within the internal space 734 near the nozzle 524 of the syringe body 520. In some embodiments, by the second biasing mechanism 730, the valve body 720 translates such that the flange 735 of the valve body 720 is pressed against the internal lip 736 of the nozzle 524. Further, the biasing mechanism 724 can seal and block the flow through the valve body 720 until sufficient force is applied to the ball 722 to overcome the biasing force. This can occur when the pressure difference between the mixing chamber 510b and the atmosphere exceeds a threshold value.

[0092] During operation, the second pressure regulating system 710b is opened by an increase in the pressure contained within the mixing chamber 510b during the first and second operating phases. When the pressure difference for opening the valve body 720 becomes insufficient, the second operating phase is completed and the user can transition to the third operating phase.

[0093] Referring to FIG. 14, the filter 760 is attached to the outlet of the second pressure regulating system 710b. The filter 760 has a first open end 762 having a flange 764 configured to engage the internal threads of the threaded nozzle 524, a second open end 766, and a filter element 768 positioned between the first open end 762 and the second open end 766. Thus, gas can pass in both directions between the first open end 762 and the second open end 766 and can be filtered in this process.

[0094] In some embodiments, the inner surface of the first opening end 762 tapers in the direction of the second opening end 766 such that its shape corresponds to the shape of the valve body 720. When the attachment 760 is screwed into the threaded nozzle 524, the attachment 760 engages the valve body 720 and translates the valve body 720 toward the rear end of the syringe body 520 against the biasing force of the second biasing mechanism 730. This brings the ball 722 into contact with the pin actuator 732, thereby separating the ball from the inner surface of the valve body 720 and enabling gas to flow in either direction within the valve body 720. This configuration can enable further expansion of the mixing chamber 510b at atmospheric pressure and filtering of the air drawn into the mixing chamber 510b. Accordingly, at this position, a third operating stage can be implemented. Once the third operating stage is completed, the filter 760 can be removed. The valve body 720 remains closed by the force of the second biasing mechanism 730 until the user decides to use the therapeutic gas within the mixing chamber 510, for example, by attaching an injection needle for injecting the therapeutic gas into a patient, and the valve body 720 can be translated away from the pin actuator 732.

[0095] Embodiments of a measurement control system and an activation system Figures 15 - 31 illustrate further embodiments of the components of the measurement control system of the device.

[0096] Figures 15A and 15B illustrate one embodiment of a measurement dial 820 that can be configured to enable a user of the device to select the concentration of a fluid of injectable volume. Similar to other embodiments, the measurement dial 820 can include two components such as a measurement body 822 and a measurement cap 824 that can be removably attached to the measurement body 822.

[0097] Continuing to refer to FIGS. 15A and 15B, the measurement body 822 can have a substantially cylindrical member 830, with a flange 832 located at the upper portion of the measurement body 822. The measurement body 822 is substantially at the center of the cylindrical member 830 and can include a channel 834 that extends throughout the measurement body 822. In some embodiments, such as those shown in FIG. 15A, the substantially cylindrical member 830 can include additional surface features, such as a diameter increase portion 831 that can be optionally fixed to a device for inserting the substantially cylindrical member 830.

[0098] Similar to other embodiments of a measurement dial or similar measurement mechanism, this embodiment can also include a measurement indicator 836 located along the surface of the measurement body 820. In this illustrated embodiment, the measurement indicator 836 is located on the top surface of the flange 832, but any other visible location can be used, such as along the periphery of the flange 832. In the illustrated embodiment, the measurement indicator 836 indicates numbers in the ranges of 18, 19, 20, 21, and 22 corresponding to the concentration of sulfur hexafluoride (SF6) that can be generated within the injectable volume of the assembly.

[0099] Similar to other embodiments of a measurement dial and other measurement mechanisms, the measurement body 822 can have slots 838, rails 840, and variable stops corresponding to the measurement indicator 836.

[0100] The operation of the variable stop of the illustrated embodiment of the measurement dial 820 can be similar to that of other embodiments of measurement dials and measurement mechanisms. The variable stop can be configured to interact with components housed within the plunger body 860, such as a latch 928 or similar protruding structure, to control the expansion of the injectable volume chamber during at least some operating stages. In some embodiments, the variable stop can perform this task by restricting the rearward extension of the plunger body 860 during different stages. Thus, the variable stop extends different distances depending on the concentration to which the stop corresponds.

[0101] Referring to FIG. 16, there is shown an embodiment of a plunger body 860 that can include a generally cylindrical frame 862, a handle 864 at one end of the plunger body 860, a selector member 866 positioned between the generally cylindrical frame 862 and the handle 864, and a channel 868 that is centered within the cylindrical frame 862 and can extend over the entire length of the plunger body 860 or at least a portion of the length of the cylindrical frame 862. The cylindrical frame 862 can be configured to translate slidably and rotate slidably within the channel of the measuring dial.

[0102] Continuing to refer to FIG. 16, the cylindrical frame 862 can include a latch aperture 874 positioned on the activation rod 920 and configured to allow a latch 928 housed within the channel 868 to project outwardly from the cylindrical frame 862. As shown in the illustrated embodiment, the latch aperture 874 can be disposed centrally directly above the top of the guard 872. In other embodiments, the latch aperture 874 can be positioned at different locations along the cylindrical frame 862 and can include two or more latch apertures if multiple latches are used.

[0103] As described in more detail below, the latch 928 is sized such that in a first, “initial” or “pre-activation” position, it does not extend beyond the guard 872 and thus cannot contact a variable stop or similar structure. When in a second or “open” position, the latch 928 can extend outwardly beyond the guard 872 from the cylindrical frame 862 such that the latch 928 can contact a variable stop or similar structure, thereby preventing or significantly reducing the possibility that the plunger body 860 extends further while the latch is in the second position.

[0104] Continuing to refer to FIGS. 16, 25a and 25b, the activation switch 960 can be configured to translate the actuator rod 920 through the plunger body 860 towards the first housing member 1020 to activate a mechanism for releasing the gas contained within the first housing member 1020. Thus, the activation switch 960, such as activation switches of other embodiments, can be a cam having a curved outer shape 962 located along a surface configured to contact the actuator body 922. The activation switch 960 can additionally include an aperture 964 configured to receive a pin such that the activation switch 960 can rotate about the pin. It will be understood by those skilled in the art that the activation switch 960 can preferably be any type of switch that can remain in a first position, a second position or more positions without the user having to maintain the switch in that position. In the illustrated embodiment, a rotary lever is used. Other switches can also be used, such as screws, latches, spring-loaded pins or any other switch well-known in the art.

[0105] Referring to FIG. 18, the activation switch 960 in a first, “initial” or “pre-activation” position is shown. For example, this can be a position before the first operating stage. In this first position, the distance between the pin 966 and the actuator body 922 and the curved surface 962 in contact therewith can be a first distance such that the actuator body 922 is located at a first distance from the end of the cylindrical frame 862 of the plunger body 860.

[0106] As shown in FIG. 19, in some embodiments, the activation switch 960 can be rotated toward a second or “open” position that is more vertically oriented. In this position, the distance from the pin 966 to the curved surface 962 that contacts the actuator body 922 can be a second distance such that the actuator body 922 is located at a second distance from the end of the cylindrical frame 862 of the plunger body 860. This can correspond to the position of the activation switch 960 during the first and second operating phases. In some embodiments, the second distance can be greater than the first distance. As will be described in more detail with respect to FIGS. 25-27, this can translate the actuator body 922 toward the first housing member 1020 of the pressure chamber. This translation can initiate the release of fluid or gas contained within the pressure chamber.

[0107] As shown in FIG. 20, in some embodiments, the activation switch 960 can also be rotated toward a third or “closed” position that is more horizontally oriented. In this position, the distance from the pin 966 to the curved surface 962 that contacts the actuator body 922 can be a third distance such that the actuator body 922 is located at a third distance from the end of the cylindrical frame 862 of the plunger body 860. This can correspond to the third operating phase and / or the final phase before injecting the injectable volume into the patient. This third distance can be less than or equal to the first distance and / or the second distance. In some embodiments, rotation to the third position can translate the actuator body 922 away from the first housing member 1020 of the pressure chamber so that fluid or gas is not released from the pressure chamber.

[0108] Optionally, an interlock mechanism can be included to control and limit the movement of the activation switch 960.

[0109] Referring to FIGS. 21 - 23, the operation of one embodiment of the startup system is shown. As shown in the illustrated embodiment and other similar embodiments, the latch 928 can be housed within the latch aperture 874 such that the latch cannot translate toward the front or rear end of the plunger body 860. In such an embodiment, when the actuator rod 920 translates in the forward or rearward direction, the latch 928 is configured to follow the outer profile of the latch movement portion 926 of the actuator rod 920.

[0110] FIG. 21 shows the embodiment in the first, “initial” or “pre - startup” position. As shown here, when extended rearward, the latch 928 can be arranged to protrude sufficiently outward from the plunger body 860 such that the latch 928 contacts a variable stop located on the measurement body 922 and further extension is prevented. In other embodiments, when in the first position, the latch 928 can be configured not to protrude outward from the body 860 to prevent such extension. When moving to the second or “open” position as shown in FIG. 22, the latch 928 can protrude sufficiently outward from the plunger body 860 such that the latch 928 contacts a variable stop or similar structure located on the measurement dial 820 and thereby can prevent any further rearward extension. When rotating to the third or “closed” position as shown in FIG. 23, the latch 928 can be sufficiently retracted into the latch aperture 874 such that the latch 928 no longer contacts a variable stop or similar structure located on the measurement dial 820, thereby allowing the plunger body 860 to extend further rearward.

[0111] Continuing to refer to FIGS. 21 - 23, a ratchet member 886, such as a pole, can be attached to the plunger body 860. The ratchet member 886 is hinge - connected and can be configured to be movably deformable and to provide resistance during deformation. The ratchet member 886 can correspond to features located on the plunger body measurement dial 820, such as the notch 842 (FIG. 15b), to encourage an appropriate orientation for a selected concentration. To allow for inward deformation of the ratchet member 886, the actuator body 924 can include a recess or depression 980. This recess 980 can be configured to allow the ratchet member 886 to deform inwardly only at the first and third positions, while restricting inward deformation while the ratchet member 886 is in the second position. Thereby, means can be provided to reduce the possibility that the plunger body 860 can rotate during operation of the device.

[0112] Embodiments of the pressure chamber Referring to FIGS. 24 - 25B, an embodiment of the pressure chamber is shown in conjunction with the components of the activation system. As shown, the pressure chamber can have a two - part housing having a first housing member 1020 and a second housing member 1022 that are translatable relative to each other. As shown in the illustrated embodiment, the two members 1020, 1022 can have a generally cylindrical shape such that a portion or all of the two members 1020, 1022 can be received within the channel 868 of the plunger body 860. In some embodiments, the two members 1020, 1022 can be separated from each other to allow for free translation of the two members 1020, 1022. In other embodiments, the two - part housing can be attached while still allowing translation of the members 1020, 1022 relative to each other. Such attachment can be used to increase the stability of the two members 1020, 1022.

[0113] As shown in the illustrated embodiment and as in other embodiments of the pressure chamber, an annular slot 1024 can be located on the second housing member 1022. In the illustrated embodiment, the annular slot 1024 is located at an end facing the first housing member 1020. However, other possible locations can also be selected. The annular slot 1024 is sized and configured to receive the retaining wing 870 (FIG. 25A) of the plunger body 860 and can enable fastening of the second housing member 1022 to the plunger body 860 using a snap-fit connection. To facilitate insertion of the second housing member 1022 into the channel 868 of the plunger body 860, the inserted end portion can be slightly tapered. In some embodiments, the second housing member 1022 can be removably attached to the plunger body 860, thereby enabling replacement of certain components housed within the second housing member 1022. For example, in some embodiments, the storage member 1030 or canister can be housed within a two-part housing. The two-part housing can also have a plunger end 1060. The plunger end 1060 has a plunger seal 1061, such as a rubber O-ring, configured to form a seal that sealingly contacts the syringe body 1120 and defines a chamber for containing an injectable volume (such a chamber can function as a mixing chamber in some cases). Other types of sealing members can also be used around the plunger end 1060 to form such a seal.

[0114] Figures 25A and 25B are cross-sectional views of the embodiment shown in FIG. 24 when the device is in the first, “initial” or “pre-activation” position. As shown more clearly in FIG. 25B, in the first position, a rod biasing member 924, such as a coil spring, can contact both the actuator body 922 and the first housing member 1020. However, the actuator body 922 does not necessarily have to contact the first housing member 1020 directly. In the first position, the rod biasing member 924 can apply a forward force to the first housing member 1020 and can apply a rearward force to the actuator body 922 such that the actuator body 922 remains in contact with the activation switch 960. In this position, due to the forward force on the first housing member 1020, when the first housing member 1020 attempts to translate towards the second housing member 1022, the first housing member 1020 can apply a force to the storage member 1030 housed therein. Preferably, in the first position, due to the mechanism (described in more detail in FIGS. 28 - 29) housed within the storage member 1030, the force applied by the first housing member 1020 to the storage member 1030 is insufficient to translate the storage member 1030 towards the second housing member 1022. Thus, while in the first position, any gas or fluid housed within the storage member 1030 remains housed within the storage member 1030.

[0115] Figures 26A and 26B are cross-sectional views of the embodiment shown in FIG. 24 when the device is in the second or “open” position. As is more clearly shown in FIG. 26B, while in the second position, both the actuator body 922 and the rod biasing member 924 can be in direct contact with the first housing member 1020. This direct contact allows the first housing member 1020 to translate in the forward direction, thereby applying a greater force to the first housing member 1020 to translate the storage member 1030 in the forward direction. Thereafter, this forward translation of the storage member 1030 can activate the release of gas from the storage member 1030. In other embodiments, the actuator body 922 need not be in direct contact with the first housing member 1020. This is because, in such embodiments, the increase in the force applied by the rod biasing member 924 due to compression of the rod biasing member 924 can be sufficient to translate the first housing member 1020 in the forward direction and cause activation of the release of gas from the storage member 1030.

[0116] Figures 27A and 27B are cross-sectional views of the second embodiment shown in FIG. 24 when the device is in the third or “closed” position. As shown in FIG. 27B, while in the third position, the actuator body 922 is in contact with the first housing member 1020. Further, in some embodiments, due to a decrease in the distance between the pin 966 and the curved surface 962, the actuator body 922 can be translated toward the curved surface 962 by a force acting on the actuator body 922 in the rearward direction by the rod biasing member 924 such that the actuator body 922 remains in contact with the activation switch 960. This expansion of the rod biasing member 924 results in a decrease in the force exerted on the first housing member 1020 by the rod biasing member 924. As a result of this decreased force and the result of the storage member 1030 or other mechanisms located within the canister, the storage member 1030 can return to the closed state, thereby preventing any additional gas from being released into the chamber that can also function as a mixing chamber and that houses the injectable volume.

[0117] Figure 28 is a cross-sectional view of an embodiment of the pressure chamber. The first and second housing members 1020, 1022 contain therein a storage member 1030 such as a microcylinder or a canister that houses a fluid such as a gas. In some embodiments, the second member 1022 has a plunger end 1060 at an end opposite the first member 1020 that forms a conical or frustoconical surface. In some embodiments, the second member 1022 and the plunger end 1060 form an integral unit. The plunger end 1060 may have an annular slot configured to receive a plunger seal 1061 such as a rubber O-ring to form an injectable volume chamber that can also function as a mixing chamber.

[0118] The first housing member 1020 may include a recessed portion 1026 or a depression configured to contact and receive the first end of the storage member 1030. The shape of the recessed portion 1026 should preferably correspond to the shape of the first end of the storage member 1030. In other embodiments, the first housing member 1020 may not include the recessed portion 1026. The second housing member 1022 may include an internal space 1028 sized and configured to receive the second end of the storage member 1030. In some embodiments, the internal space 1028 may include a housing seal 1029 that contacts the second end of the storage member 1030. In some embodiments, the housing seal 1029 creates a sufficient seal such that there is little gas leakage rearward through the internal space 1028. In some embodiments, the internal space 1028 can also provide a generally tight fit around the storage member 1030 to ensure that the storage member 1030 translates generally only in the forward and rearward directions. This advantageously reduces the likelihood of damage to the seal between the second end of the storage member 1030 and the housing seal 1029.

[0119] Continuing to refer to FIG. 28, a storage member 1030, such as a canister or microcylinder shown, may include a body portion 1040 and a head 1042. As shown in the illustrated embodiment, the body portion 1040 may have a generally cylindrical shape with a hemispherical first end. The body portion 1040, together with the head 1042, can form an internal volume 1041 for containing a fluid, such as a gas in either gaseous or liquid form or a combination of both, at a first pressure and concentration that can be different from the ambient gas. For example, such gases may include, but are not limited to, expansive gases, ophthalmic gases such as SF6, C3F8, C2F6 or similar gases, propellant gases such as CO2, refrigerant gases such as N2O and various other types of gases. The size of the internal space 1041 can be selected such that a unit or single-use dose can be contained within the volume. Other shapes can also be selected for the body portion 1040.

[0120] The head 1042 can have a generally cylindrical shape with an outer diameter that matches the inner diameter of the body portion 1040. The head 1042 can have an internal channel and a flange 1044. As shown in the illustrated embodiment, the first end of the head 1042 can have an opening with a diameter that matches the diameter of the channel, and the second end of the head can have an opening 1046 with a diameter smaller than the diameter of the channel. In some embodiments, the body portion 1040 and the head 1042 can be separate components that are attached later. This can advantageously allow for the assembly of the internal components of the head 1042 prior to assembly, in some cases. Once all the components within the head 1042 are assembled, the head 1042 can be received within the body portion 1040 and fastened using devices and mechanisms such as adhesives, welding, etc. In some embodiments, such as those shown in FIG. 28, the flange 1044 can abut against the body portion 1040 and be adhered or welded along this surface. In other embodiments, the body portion 1040 and the head 1042 can form an integral unit.

[0121] The head 1042 can accommodate a storage member pressure adjustment system. The storage member pressure adjustment system can form part of the first pressure adjustment system and can take the form of an internal valve mechanism within the channel. The internal valve mechanism can include a retaining ring 1048, a valve seat 1050, an internal biasing member or mechanism 1052 such as a spring, a valve piston 1054, and a piston seal 1056. The retaining ring 1048 can be disposed within an annular slot 1058 located on the head 1042. The retaining ring 1048 can be made of an elastic material so that it can be deformed before the retaining ring fits into the slot 1058. The valve seat 1050 can be disposed between the retaining ring 1048 and the second end of the head 1042. In some embodiments, the valve seat 1050 can be a ring having an outer diameter that is substantially equal to the inner diameter of the head 1042.

[0122] The valve piston 1054 can have a generally cylindrical shape and can be disposed between the valve seat 1050 and the second end of the head 1042. The outer diameter of the valve piston 1054 can be selected to be substantially equal to the inner diameter of the head 1042. As shown in the illustrated embodiment, the valve piston can include an annular slot configured to receive a piston seal 1056, a fluid path 1055 or channel located along the perimeter of the piston, and a protrusion 1057. The fluid path 1055 can be configured to allow fluid to pass between the valve piston 1054 and the head 1042. In the illustrated embodiment, a total of four fluid paths are included, although fewer or more paths can be used. In some embodiments, the protrusion 1057 can be a cylindrical member having a diameter smaller than the diameter of the opening 1046. The protrusion 1057 can be configured to fit within the opening 1046. In some embodiments, the protrusion 1057 can be flush with the end face of the head 1042. In other embodiments, the protrusion 1057 can retract into the opening or extend beyond the end face. A biasing mechanism 1052 for applying a forward force to the valve piston 1054 can be disposed between the valve seat 1050 and the piston 1054 so that a seal is formed between the piston seal 1056 and the head 1042. In other embodiments, other types of valve designs can be used, such as ball valves, poppet valves, or any other valve mentioned herein or well-known in the art.

[0123] In some embodiments, the internal biasing mechanism 1052 can be configured such that when the activation switch is in the first or “pre-activation” position, the internal valve mechanism is not opened by any force applied to the internal valve mechanism, such as the force applied to the storage member 1030 by the rod biasing mechanism 924 via the first housing member 1020. In some embodiments, the internal biasing mechanism 1052 can be configured such that when the activation switch is in the second or “open” position, the internal valve mechanism is opened by the force applied to the internal valve mechanism. In some embodiments, the internal biasing mechanism 1052 can be configured such that when the activation switch is in the third or “closed” position, the internal valve mechanism is not opened by any force applied to the internal valve mechanism, such as the force applied to the storage member 1030 by the rod biasing mechanism 924 via the first housing member 1020.

[0124] In some embodiments, the storage member 1030 can include other structures such as a filter built into a portion of the storage member 1030, such as the head 1042. The storage member 1030 can include a membrane or other sealing structure disposed on the head 1042 and on the opening 1046 to provide an additional seal that can advantageously extend the shelf life of the storage member 1030. The membrane or sealing structure can be pierced by a protruding member such as the pin 1059 or any other similar release mechanism. In some embodiments, the release mechanism can be a porous material known as a “frit,” for example. The storage member 1030 can also include an additional valve member that can function as a relief valve to reduce the possibility of rupture when the pressure contained within the storage member 1030 exceeds a certain operating limit. The storage member 1030 can also be configured to rupture in a controlled manner to reduce the potential for catastrophic damage.

[0125] In some embodiments, internal components such as the storage member 1030 and the internal valve are manufactured from small and lightweight materials. The materials can also be flexible. In some embodiments, the material and dimensions of the storage member 1030 can be selected such that the storage member 1030 withstands the diffusion of gas through the walls of the storage member 1030. This can provide the advantage of increasing the storage life of the storage member 1030 when gas is contained within the storage member 1030. In some embodiments, the length of the storage member 1030 from the rearmost end of the body 1040 to the foremost end of the head 1042 can be in the range of about 15 mm to about 65 mm, such as about 20 mm to about 45 mm and 29 mm, about 25 mm to about 35 mm. In some embodiments, the outer diameter of the body 1040 can be in the range of about 4 mm to about 25 mm, such as about 6 mm to about 20 mm and 9.5 mm, about 8 mm to about 15 mm. In some embodiments, the outer diameter of the head 1042 without the flange portion can be in the range of about 2 mm to about 20 mm, such as about 4 mm to about 15 mm and 7.5 mm, about 6 mm to about 10 mm.

[0126] Continuing to refer to FIG. 28, the pin 1059 that can function as a release mechanism can be located within the channel 1062. The release mechanism 1059 can be disposed substantially centrally on the protrusion 1057 of the valve piston 1054, can have a diameter that matches the diameter of the opening 1046, and can define a through passage (not shown). As shown in FIG. 29, when the storage member 1030 translates in the forward direction toward the release mechanism 1059 during operation such that the release mechanism 1059 retracts the valve piston 1056 from the head 1042, thereby allowing fluid flow to pass from the storage member 1030 over the path 1055 and the release mechanism 1059, through the channel 1062, and ultimately into a chamber of an injectable volume such as a mixing chamber, the release mechanism 1059 remains stationary. In some embodiments, the release mechanism 1059 can include internal or external channels, or can be made of a porous material such that the release mechanism 1059 itself functions as a preliminary filtering mechanism for the fluid flowing within the channel 1062. In some embodiments, a filter can be added between the release mechanism 1059 and the end of the channel 1062 or at any other location to filter and remove materials.

[0127] Referring to FIGS. 30 - 32, a further embodiment of a surgical kit 2c including a container 4c having a gas mixing device 10c is shown. The gas mixing device 10c can include the same or similar components as those described above with reference to the gas mixing devices 10, 10a, and 10b, except as otherwise shown below.

[0128] The mixing device 10c can include a chamber of an injectable volume such as a mixing chamber. The mixing chamber can include a syringe body 1120, a syringe pressure adjustment system that can form part of a second pressure adjustment system, and various components of the systems described above. The syringe body 1120 can have a cylindrical body and a protrusion 1122 at the front end.

[0129] In some embodiments, the threaded nozzle 1124, which may include multiple components of the pressure adjustment system, can be removably attached to the protrusion 1122 of the syringe body 1120. This can advantageously facilitate the assembly of the device by enabling the pressure adjustment system to be assembled within the smaller nozzle 1124 before being incorporated into the syringe body 1120. The nozzle 1124 can be attached to the protrusion 1122 using a plurality of fastening devices and means such as screws, adhesives, snap fits, welding, etc. The injectable volume chamber can be defined by the inner wall of the syringe body 1120 and the plunger seal 1061. Further, similar to other embodiments of the syringe, the syringe body 1120 can also include an indicator corresponding to a selected concentration along its outer surface and a flange at the rear end of the body 1120 configured to be attached to a measurement dial. Optionally, the surgical kit 2c can include a flow restrictor 1300 connected to the 761c of the filter device 760c.

[0130] Continuing to refer to FIGS. 30 - 32, an embodiment of a syringe pressure adjustment system is shown that includes a valve body 1220, a valve end 1222, a valve piston 1224, a piston seal 1226, a piston biasing member or mechanism 1228, a valve biasing member or mechanism 1230, and a valve end seal 1232. Similar to other embodiments of the pressure adjustment system, the valve body 1220 and the valve end 1222 can slide translationally within the threaded nozzle 1124.

[0131] At a first position, such as the position shown in FIG. 32, due to the force acting in the forward direction on the valve body 1220 and the valve end 1222 by the valve biasing member 1230, the valve end 1222 can rest on the shoulder 1234 of the threaded nozzle 1124. At the first position, the valve piston 1224 and the valve seal 1226 can form a seal and can restrict or prevent fluid from passing through the valve body 1220. However, when the pressure in the injectable volume chamber increases beyond a threshold for overcoming the biasing force exerted by the piston biasing member 1228, the valve piston 1224 can translate in the forward direction against the force applied by the piston biasing member 1228, and the fluid can pass through the valve body 1220 and the valve end 1222 and enter the atmosphere. When the pressure drops back to the threshold, due to the balance of forces, the valve piston 1224 and the valve seal 1226 can again come into sealing contact with the valve body 1220.

[0132] At a second position, the valve body 1220 and the valve end 1222 can translate in the rearward direction against the valve biasing member 1230. For example, this can be achieved by applying a rearward force to the valve end 1222. At the second position, the contact between the valve piston 1224 and the internal protruding member 1126 of the syringe body 1120 can move the valve piston 1224 in the rearward direction relative to the valve body 1220 and the valve end 1222 so that the valve piston 1224 no longer makes sealing contact with the valve body 1220. In some embodiments, this can enable the passage of fluid to and from the injectable volume chamber. In some embodiments, when the in-line filter 760c is screwed onto the threaded nozzle 1124, the pressure adjustment system can be forced into the second position. Other types of attachments, such as stoppers, valves, tubes, etc., can also be attached to the threaded nozzle 1124.

[0133] Referring to FIGS. 32-35, the flow restrictor 1300c can be in the form of a cap configured to engage the outlets of the filter devices 760c and 761c. For example, the flow restrictor 1300c can include a threaded end 1032 configured to engage the threads on the inner surface of the outlet 761c. Further, the flow restrictor 1300c can include any finger grip 1304 configured to facilitate gripping with a finger to ease removal of the flow restrictor 1300c when wearing surgical gloves.

[0134] The flow restrictor can also include a flow restriction port 1306. In some embodiments, the minimum diameter of the port 1306 can be made smaller than the minimum diameter of the outlet opening 1308 of the outlet 761c (FIG. 30). Accordingly, the minimum cross-sectional area of the outlet port 1306 can be smaller than the minimum cross-sectional area of the outlet opening 1308. Thus, it is as described above with reference to FIG. 1A and the flow restrictor 1300c. Continuing to refer to FIG. 30, the operating mixing device 10c can be packaged within the container 4c to form a surgical kit 2c. Similar to the other mixing devices 10, 10a, 10, and 10b, the mixing device 10c can be packaged within the container 4c with the filter device 760c pre-attached in a sterile state and can optionally also include the flow restrictor 1300.

[0135] In use, a physician or other user can remove the mixing device 10c with the filter 760c pre-attached from the package 4c. Thereafter, the user can supply a treatment gas and / or components of the treatment gas to the mixing chamber of the device 10c and move the plunger 1061 away from the filter device 760c (as seen in FIG. 30) until the plunger 1061 moves to a position corresponding to the desired volume of the treatment gas that provides the desired concentration of the mixed gas. After the plunger 1061 has moved to the desired position, the excess treatment gas can be discharged through the filter device 760c. Thus, since the filter device 760c is pre-attached to the mixing device 10c, it is never the case that unfiltered air is present in any open volume between the filter member 763 of the filter device 760c and the plunger 1061. Thus, during the discharge of the treatment gas through this filter device 760c, no contaminants, foreign matter or unwanted gases are trapped upstream of the filter member 763.

[0136] After the desired volume of the treatment gas or components of the treatment gas is contained within the mixing chamber, the user can manually move the plunger 1061 further away from the filter device 760c, thereby drawing air through the outlet 761c of the filter device 760c, through the filter member 763 and into the mixing chamber. Thus, the filter member 763 can filter out and remove any particulate matter, foreign matter or unwanted gases and prevent such from entering the mixing chamber. After the mixing chamber has expanded to the desired volume, thereby forming a treatment mixture of the desired concentration, the filter device 760c can be removed and instead a further delivery device can be connected. For example, a subcutaneous needle can be attached in place of the filter device 760c for the delivery of the treatment gas.

[0137] As described above, the mixing device 10c can optionally be packaged within the container 4c with the flow restrictor 1300c pre-attached. Pre-attaching the flow restrictor 1300c provides additional backpressure during the discharge of excess gas, thereby serving to ensure that the plunger 1061 is fully pressed against any limiting device for defining a predetermined volume of the therapeutic gas or components of the therapeutic gas within the syringe body 1120, offering any additional benefit that can be so useful.

[0138] In some embodiments, the pressurizing chamber can be external to the device. In such embodiments, the pressurizing chamber can be a tank or other canister that houses a gas in liquid or gaseous (or a combination thereof) form. In some embodiments, the tank can be attached to the threaded nozzle via a tube or other mechanism. The connection between the threaded nozzle and the tube can be used to forcefully open a pressure regulating system located on the device, thereby enabling gas from the tank to be introduced into the chamber. In some embodiments, the introduction of gas from the tank can be carried out during the first operating phase. Thus, the device can be filled with gas from the tank until it reaches a set first volume. In some embodiments, the tank can have a regulator such that the device is filled with gas at a regulated pressure. Thereafter, the connection can be removed from the threaded nozzle, enabling the valve to function properly. In some embodiments, the gas can potentially be at a pressure higher than the atmosphere and can exceed the threshold of the pressure regulating system, so the gas can be discharged or released from the system until the set pressure of the device is achieved. Once the set pressure within the device is achieved, the remaining operating phases can then be completed in a manner similar to the methods of the above-described embodiments.

[0139] The foregoing description pertains to an apparatus and method for mixing and / or injecting gases that have certain features, aspects, and advantages according to the present invention. Various modifications and variations can be made to the gas mixing apparatus and method described above without departing from the spirit and scope of the present invention. Thus, for example, one skilled in the art will understand that the present invention can be embodied or practiced in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objectives or advantages that may be taught or suggested herein. Further, although some variations of the present invention have been shown and described in detail, other modifications and methods of use within the scope of the present invention will be readily apparent to those skilled in the art based on this disclosure. It is possible to create various combinations or sub-combinations of specific features and aspects of the embodiments, and these are considered to still be within the scope of the present invention. Accordingly, it should be understood that the various features and aspects of the disclosed embodiments can be combined with each other or substituted for each other to form various aspects of the disclosed gas mixing apparatus.

Claims

1. 1. A handheld gas injector for delivering therapeutic gas to a patient, comprising: a syringe body having an outlet; a plunger slidably disposed within and with the syringe body, the plunger defining a first chamber within the syringe body; a second chamber disposed within at least one of the syringe body and the plunger, an interior volume containing at least a first fluid having a concentration different from that in the atmosphere and a pressure greater than that of the surrounding atmosphere; an opening at a first end of the second chamber; a first valve mechanism located adjacent the first end and configured to seal the opening; and a second chamber including a channel and an aperture between the second chamber and the first chamber; an actuation system operably coupled to the second chamber, the actuation system configured to cause the release of the first fluid from the second chamber through the channel to the first chamber; an adjustable volume limiter configured to limit movement of the plunger to a plurality of user-selectable positions corresponding to a plurality of volumes of the first chamber; a filter having a first end connected to the outlet of the syringe body, a second end having a filter orifice, and a filter element disposed between the first end and the second end; a flow restrictor connected to the filter orifice and having a restrictor orifice smaller than the filter orifice, configured to restrict the flow of fluid from the first chamber through the filter orifice such that the first fluid from the second chamber travels from the second chamber through the first valve mechanism adjacent the first end of the second chamber, through the first chamber, through the first end of the filter, through the filter, through a second end of the filter having the filter orifice, and then through the restrictor orifice of the flow restrictor to an exterior of the handheld gas injector; Including, the flow restrictor is configured to create a back pressure against fluid flow from the first chamber to expand the first chamber to a desired volume corresponding to a user selected position of the adjustable volume limiter.

2. 2. The handheld gas injector of claim 1, wherein the filter is removably connected to the syringe body.

3. 2. The handheld gas injector of claim 1, wherein the flow restrictor includes a bore having a first end configured to receive fluid from the filter orifice and a second end including the restrictor orifice, the bore tapering between the first end and the second end.

4. 1. A handheld gas injector assembly comprising: a syringe body having an outlet; a plunger slidably disposed within and with the syringe body, the plunger defining a first chamber within the syringe body; an adjustable volume limiter configured to limit movement of the plunger to a plurality of user-selectable positions corresponding to a plurality of volumes of the first chamber; a filter having a first end connected to the outlet of the syringe and a second end having a filter orifice; a flow restrictor connected to the filter orifice and having a restrictor orifice smaller than the filter orifice, the flow restrictor configured to restrict the flow of fluid from the first chamber through the filter orifice such that fluid exiting the syringe travels through the first end of the filter, through the filter, through the second end of the filter having the filter orifice, and then through the restrictor orifice of the flow restrictor to an exterior of the hand-held gas injector assembly; Including, the flow restrictor is configured to create a back pressure against fluid flow from the first chamber to expand the first chamber to a desired volume corresponding to a user selected position of the adjustable volume limiter.

5. 5. The handheld gas injector assembly of claim 4, further comprising a fill mechanism configured to direct a first fluid into the first chamber.

6. 5. The handheld gas injector assembly of claim 4, wherein the filter is removably connected to the syringe body.

7. 5. The handheld gas injector assembly of claim 4, wherein the flow restrictor includes a bore having a first end configured to receive fluid from the filter orifice and a second end including the restrictor orifice, the bore tapering from a larger size at the first end to a smaller size at the second end.

8. 5. The handheld gas injector assembly of claim 4, further comprising a valve mechanism having a first position and a second position, the valve mechanism configured to prevent fluid flow from the first chamber when in the first position and to allow fluid flow from the first chamber when in the second position.

9. 1. A handheld gas injector assembly comprising: a syringe body including an end wall and an outlet connected to the end wall; a plunger slidably disposed within and with the syringe body, the plunger being disposed within the syringe body and at the end wall of the syringe body to define a first chamber between the plunger and the end wall, the first chamber comprising a volume definable by movement of the plunger; a second chamber, the second chamber including at least an interior volume containing a first fluid at a concentration different from that in atmospheric air and at a pressure above the pressure of the ambient atmosphere, the second chamber fluidly coupled to the first chamber for release of the first fluid from the second chamber to the first chamber; a filter having a first end connected to the outlet of the syringe and a second end having a filter orifice; a flow restrictor connected to the filter orifice and configured to restrict a flow of the first fluid from the first chamber through the filter orifice, the restrictor orifice being smaller than the filter orifice such that the first fluid exiting the syringe body travels through the first end of the filter, through the filter, through a second end of the filter having the filter orifice, and then through a restrictor orifice of the flow restrictor to an exterior of the hand-held gas injector assembly; an adjustable volume limiter configured to limit movement of the plunger to a plurality of user-selectable positions corresponding to a plurality of volumes of the first chamber; Including, the flow restrictor is configured to create a back pressure against fluid flow from the first chamber to expand the first chamber to a desired volume corresponding to a user selected position of the adjustable volume limiter of the handheld gas injector assembly.

10. 10. The handheld gas injector assembly of claim 9, further comprising a fill mechanism configured to direct a first fluid into the first chamber.

11. 10. The handheld gas injector assembly of claim 9, wherein the filter is removably connected to the syringe body.

12. 10. The handheld gas injector assembly of claim 9, wherein the flow restrictor includes a bore having a first end configured to receive fluid from the filter orifice and a second end including a restrictor orifice, the bore tapering between the first end and the second end.

13. 10. The handheld gas injector assembly of claim 9, further comprising a valve mechanism configured to move between a first position and a second position, the valve mechanism configured to block fluid flow from the first chamber when in the first position and to allow fluid flow from the first chamber when in the second position.

14. 14. The handheld gas injector assembly of claim 13, wherein the valve mechanism includes a valve disc, a piston, a seal, a valve biasing member, and an internal projection member.

15. 14. The handheld gas injector assembly of claim 13, wherein the filter is removably connected to the syringe body, and the filter is configured to engage the valve mechanism to transition the valve mechanism from the first position to the second position when the filter is coupled to the syringe body.

16. 10. The handheld gas injector assembly of claim 9, wherein the second chamber includes an opening at a first end and an internal valve mechanism located adjacent the first end and configured to seal the opening.

17. 17. The handheld gas injector assembly of claim 16, wherein the internal valve mechanism includes a piston, a seal, and a biasing member, and is configured to seal the opening at least prior to activation of the handheld gas injector assembly.

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