Patent Abstract:
An apparatus for portable delivery of nitric oxide without the need for pressurized tanks, power supplies, or other devices provides a single therapy session by triggering a heater to heat a reaction chamber. A piercing assembly may trigger to open sealed containers, such as bags, of liquid water or salt water in order to activate the heaters. Upon addition of liquid such as water or salt water to a chemically reactive heating element, heat is generated to activate the chemicals generating nitric oxide within a sealed reactor. Upon triggering, liquid containers are unsealed, the liquid drains down to initiate reaction of the heating chemicals, and the heat begins to penetrate the reactor. The reactor, in turn, heats its contents, which react to form nitric oxide expelled by the reactor to a line feeding a cannula for therapy.

Full Description:
RELATED APPLICATIONS 
     This patent application: is a divisional of U.S. patent application Ser. No. 12/419,123, filed Apr. 6, 2009, issued as U.S. Pat. No. 9,138,707 which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/043,064, filed Apr. 7, 2008, and is a continuation in part of U.S. patent application Ser. No. 11/751,523, filed May 21, 2007, issued as U.S. Pat. No. 7,939,045, on May 10, 2011, which is a continuation-in-part of U.S. patent application Ser. No. 10/733,805, filed Dec. 10, 2003, issued as U.S. Pat. No. 7,220,393, on May 22, 2007, which claims the benefit of Canadian Patent Application Serial No. 2,413,834, filed Dec. 10, 2002. All of the foregoing applications and patents are hereby incorporated by reference in their entirety, 
    
    
     BACKGROUND 
     1. The Field of the Invention 
     This invention relates generally to chemical reactors, and more specifically to apparatus and methods for generating nitric oxide. 
     2. Background 
     The discovery of certain nitric oxide effects in live tissue garnered a Nobel prize. Much of the work in determining the mechanisms for implementing and the effects of nitric oxide administration are reported in literature. In its application however, introduction of bottled nitric oxide to the human body has traditionally been extremely expensive. The therapies, compositions, and preparations are sufficiently expensive to inhibit more widespread use of such therapies. What is needed is a comparatively inexpensive mechanism for introducing nitric oxide in a single dosage over a predetermined period of time. Also, what is needed is a simple introduction method for providing nitric oxide suitable for inhaling. 
     It would be an advance in the art to provide a single dose generator suitable for administration of nitric oxide gas. It would be an advance in the art to provide not only an independence from bottled gas, but from the need for a source of power for heat, or the like. It would be a further advance in the art to provide a disposable generator to be initiated by a trigger mechanism and operate without further supervision, adjustment, management, or the like Likewise, it would be a substantial benefit to provide a system that requires a minimum of knowledge or understanding of the system, which might still be safe for an individual user to administer with or without professional supervision. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with the foregoing, certain embodiments of an apparatus and method in accordance with the invention provide a self-contained reactor system. Nitric oxide may thus be introduced into the breathing air of a subject. Nitric oxide amounts may be engineered to deliver a therapeutically effective amount on the order of a comparatively low hundreds of parts per million, or in thousands of parts per million. For example, sufficient nitric oxide may be presented through nasal inhalation to provide approximately five thousand parts per million in breathing air. This may be diluted due to additional bypass breathing through nasal inhalation or through oral inhalation. 
     One embodiment of an apparatus and method in accordance with the present invention may rely on a small reactor. Reactive solids may be appropriately combined dry. Reactants may include compounds, such as potassium nitrite, sodium nitrite, or the like, nitrate compounds, such as potassium nitrate, sodium nitrate, or the like. The reaction may begin upon introduction of a heat. Heat may be initiated by liquid transport material to support ionic or other chemical reaction in a heat device. 
     An apparatus and method in accordance with the invention may include an insulating structure, shaped in a convenient configuration such as a rectangular box, a cylindrical container, or the like. The insulating container may be sealed either inside or out with a containment vessel to prevent leakage of liquids therefrom. Such a system need not be constructed to sustain nor contain pressure. Inside the containment vessel may be positioned heating elements such as those commercially available as chemical heaters. 
     In certain embodiments, chemical heaters may include metals finely divided to readily react with oxygen or solid oxidizers. Various other chemical compositions of modest reactivity may be used to generate heat readily without the need for a flame, electrical power, or the like. 
     Above the heating element or heater within the containment vessel may be located a reactor. The reactor may preferably contain a chemically stable composition for generating nitric oxide. Such compositions, along with their formulation techniques, shapes, processes, and the like are disclosed in U.S. patent application Ser. No. 11/751,523 and U.S. Pat. No. 7,220,393, both incorporated herein by reference in their entireties as to all that they teach. 
     The reactor may include any composition suitable for generating nitric oxide by the activation available from heat. The reactor may be substantially sealed except for an outlet, such as a tubular member secured thereto to seal a path for exit of nitric oxide from the reactor. 
     In certain embodiments, a system of water or salt water may be available in the container. In one embodiment, the water containers may be as simple as presealed bags, such as polyethylene bags that can be opened, cut, torn, or otherwise pierced in order to release water therefrom. Accordingly, a system may include a heating element or the reactor, such a water source to provide a chemical transport fluid, a piercing assembly for the water containers, a trigger for activating the piercing assembly, and blades, hooks, cutters, punches, or the like structured to open the bags containing water. 
     Upon triggering of the piercing assembly, the water is released from the water containers, vessels, bags, or the like, to be poured down through the assembly onto the heating elements where heaters are activated by the presence of a liquid. It has been found through experiments that adding the additional ionic content of salt improves the reaction rate of chemical heating systems. 
     Ultimately, an apparatus in accordance with the invention may include a cover through which an outlet penetrates from the reactor in order to connect to a cannula. This has been done effectively. It will also support a vent for steam generated by the heaters in the presence of the water used to activate the heaters. The system may be completely wrapped in a pre-packaged assembly. In one embodiment, a heat-shrinkable wrapping material may be used to seal the outer container of an apparatus in accordance with the invention. Thus, this system may be rendered tamper proof, while also being maintained in integral condition throughout its distribution, storage, and use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing features of the present invention will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are, therefore, not to be considered limiting of its scope, the invention will be described with additional specificity and detail through use of the accompanying drawings in which: 
         FIG. 1  is a perspective view of one embodiment of an apparatus in accordance with the invention to generate nitric oxide from a chemically active source of nitric oxide, as a result of exposure to heat; 
         FIG. 2  is an exploded view of the apparatus of  FIG. 1  for generating nitric oxide; 
         FIG. 3  is a top plan view of an insulating container for the apparatus of  FIG. 1 ; 
         FIG. 4  is a side elevation view of the box-like container of  FIG. 3 ; 
         FIG. 5  is an end, elevation, cross-sectional view of the container (box) of  FIGS. 3-4 ; 
         FIG. 6  is a top plan view of a cover for the container of  FIGS. 3-5 ; 
         FIG. 7  is an end elevation view of the cover of  FIG. 6 ; 
         FIG. 8  is a side elevation view of the cover of  FIG. 6 ; 
         FIG. 9  is a side elevation view of a vent for the portable nitric oxide device of  FIG. 1 ; 
         FIG. 10  is a top plan view of the vent illustrated in  FIG. 9 ; 
         FIG. 11  is a front elevation view of a triggering pin for the apparatus of  FIG. 1 ; 
         FIG. 12 a    is an end view of the pin of  FIG. 11 ; 
         FIG. 12 b    is a side elevation view of the pin of  FIG. 11 ; 
         FIG. 13  is a bottom plan view of a guiding rod for holding a compression spring used in the trigger device of the apparatus of  2 ; 
         FIG. 14  is a side elevation view of the guide rod of  FIG. 13 ; 
         FIG. 15  is a front elevation view of a spacer used in the piercing assembly of  FIG. 2 ; 
         FIG. 16  is a top plan view of the spacer of  FIG. 15 ; 
         FIG. 17  is a top plan view of the mounting assembly for a blade of the piercing assembly of the apparatus of  FIG. 2 ; 
         FIG. 18  is an end elevation view of the mounting assembly or carrier for blades in the piercing assembly of  FIG. 2 , and corresponds to the apparatus of  FIG. 17 ; 
         FIG. 19  is a side elevation view of the mounting assembly with blades in place, and corresponds to the apparatus illustrated in  FIGS. 17-18 ; 
         FIG. 20  is a side elevation view of a base or base plate for supporting the blades in the piercing assembly of the apparatus of  FIG. 2 ; 
         FIG. 21  is a top plan view of the base or base plate of the apparatus of  FIG. 20 ; 
         FIG. 22  is a side elevation view of a cover plate for the blades in the piercing assembly of the apparatus of  FIG. 2 ; 
         FIG. 23  is a top plan view of the cover plate of  FIG. 22 ; 
         FIG. 24  is a side elevation view of a spring, used as a compression spring to drive the mounting assembly of  FIG. 17 , with the blades installed to operate the piercing assembly of  FIG. 2 ; 
         FIG. 25  is a top plan view of one embodiment of a containment vessel operating as a reactor for the nitric oxide generation from the chemical species contained therein; 
         FIG. 26  is a side elevation view of the reactor&#39;s containment vessel of  FIG. 25 ; 
         FIG. 27  is a side elevation view of one embodiment of a tube configured to operate as an outlet for the reactor vessel of  FIG. 25 ; 
         FIG. 28  is a perspective view of one embodiment of a shrink-wrap sleeve that is applied to contain the overall enclosure of the apparatus of  FIGS. 1-2 ; 
         FIG. 29  is a perspective view of the apparatus of  FIGS. 1-2 ; 
         FIG. 30  is a top view of the apparatus of  FIG. 29  open for viewing of the internal apparatus; 
         FIG. 31  is a graph showing data for the temperature rise in degrees Fahrenheit of the reactor of  FIGS. 29 and 30  using a variety of heaters including a single heater relying on water as the liquid, two standard heaters relying on water, and a single heater using salt water as the activating liquid; 
         FIG. 32  is a graph depicting the temperature response of the reactor of  FIGS. 1-30  over time in both a single heater and double heater configuration; 
         FIG. 33  is a graph depicting the temperature response of the reactor of  FIGS. 1-30  as a function of time when heated by a single heater and by double heaters; and 
         FIG. 34  is a chart depicting the released volume of nitric oxide from the reactor of  FIGS. 1-30  superimposed over the temperature response thereof as a function of time. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     It will be readily understood that the components of the present invention, as generally described and illustrated in the drawings herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the system and method of the present invention, as represented in the drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of various embodiments of the invention. The illustrated embodiments of the invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. 
     Referring to  FIG. 1 , an apparatus  10  may be configured as a portable nitric oxide device. In the illustrated embodiment, a container  12  or vessel  12  may provide insulation, liquid sealing, or both. Meanwhile, a fitting  14  or outlet  14  may be connected to feed nitric oxide to a line  15  proceeding toward a user, for distribution by a cannula, mask, tent, or the like. 
     In the illustrated embodiment, a trigger  16  or actuator  16  may be withdrawn from the apparatus  10  in order to trigger the initiation of a reaction generating nitric oxide. In certain embodiments, generation of nitric oxide may depend on temperature of reactants. The generation of heat (e.g., temperature) may rely on a reaction requiring moisture, which moisture may eventually be partially converted to steam needing to be vented. Accordingly, a vent  18  may vent the interior of the container  12  in order to avoid any buildup of pressure; in one embodiment, the entire container  12  may be sealed in a heat-shrinkable sleeve that maintains the integrity of the apparatus  10  during distribution, storage, and use. 
     Referring to  FIG. 2 , an exploded view of the apparatus of  FIG. 1  illustrates one embodiment of the apparatus  10  in accordance with the invention. In the illustrated embodiment, the outlet  19 , connected to feed through the fitting  14  and thus feed nitric oxide through the line  15  may be securely sealed to a reactor  20 . The reactor  20  may be formed by any of several suitable methods to contain the chemical constituents required to generate nitric oxide. A port  21  or aperture  21  may be formed to seal against the outlet  19  in order to discharge all of the generated nitric oxide to a location outside the apparatus  10 . 
     Below or around the reactor  20  may be located one or more heaters  22  or heating elements  22 . In the illustrated embodiment, the heaters  22  are formed to contain solid reactants in a non-woven fabric container. The reactants are stabilized by being completely dry. In the presence of liquid, ionic exchange promotes the reaction of the contained chemicals within the heaters  22 . 
     In order to contain any liquid to activate the heaters  22 , a containment vessel  24  may surround the heaters  22 , within the insulation container  26  or box  26 . In certain embodiments, the functionality of the containment vessel  24  and the insulated container  26  may be consolidated into a single structure. Likewise, in certain embodiments, the containment vessel  24  may actually be located external to the insulated container  26 . 
     In general, a liquid, and particularly a hydrating liquid such as water, salt water, or the like, may serve as an activation material. In the illustrated embodiment, the bags  28  containing salt water, water, or the like may be sealed for storage. In certain embodiments, the containers  28  may be capped, vented, or otherwise made resealable. However, in other embodiments, a fully disposable apparatus  10  may rely on inexpensive materials such as polyethylene film to form the containers  28 . 
     By any means, an opening assembly  30  (in the illustrated embodiment, a piercing assembly  30 ) may be actuated to open, pierce, or otherwise breach the sealing of the containers  28  of liquid. Upon piercing or otherwise breaching of the integrity of the containers  28 , the contained liquid then flows downward to be absorbed within the covering material of the heaters  22 . The presence of the liquid activates the chemical reactions within the heaters  22 , generating heat to initiate reaction of the chemical constituents contained within the reactor  20 . 
     A cover  32  may enclose the insulated container  26 , and may typically be formed of the same material. A vent  30  may vent steam from within the containment vessel  24  and the insulated container  26  in order to alleviate any pressure build up. Likewise, in order to direct the residual steam in a specific direction other than permitting it to escape about the interface between the cover  32  and the container  26 , a vent  18  may be advisable, required, or otherwise useful. 
     The outlet  19  for nitric oxide may penetrate through the cover  32  by means of an aperture  34 . The aperture  34  may be sealed against the outlet  19  in order that the steam generated from the heaters  22  escape substantially exclusively through the vent  18 , rather than near the fitting  14  and line  15  that may be subject to manipulation by the user. 
     Referring to  FIGS. 3-8 and 29 , but referring generally to  FIGS. 3 through 24 , the insulated container  26  may be formed in any suitable shape to contain all of the elements required for a single dosing of nitric oxide. Accordingly, the constituent structures of  FIG. 2  may fit within the interior of the container  26 . Meanwhile, the cover  32  may be fitted thereto. 
     The vent  18  may be formed to fit snugly through a penetration in the cover  32 . A flange thereof may be labeled with colors and text appropriate to warn of the elevated temperature thereof as a safety measure. 
     A pin may act as a significant portion of the trigger assembly  16  or trigger  16 . Upon removal of the pin, such as by a user pulling on a handle or ring secured thereto, the blades may be released to pierce the containers  28  holding the liquid required to initiate the reaction of heaters  22 . 
     A guide  36  or guide rod  36  may direct the blades of the piercing assembly  30 . A compression spring wrapped around the guide  36  or rod  36  may push the blades forward. Referring to  FIGS. 13-23 , generally, while specifically referring to  FIGS. 15-16 , the piercing assembly  30  may be configured to protect against inadvertent exposure to sharp instruments. A spacer  38  may provide room for operation of a blade assembly  39  or mount  39  holding blades  40  secured thereto. 
     For example, a “T”-shaped mounting assembly may secure two blades  40   a ,  40   b  that will eventually slide parallel to the base of the T, and along the same direction of the guide  35  or guide rod  36 . In the illustrated embodiment, an aperture in the foot of the T-shaped mount may run along the guide rod  36 , driven by the compression spring acting along the length of the rod  36 . 
     The blade assembly or mount  39 , together with its attached blades  40  may operate by sliding along an upper surface of the baseplate  42 . Two apertures on opposing sides or near opposing edges of the baseplate  42  may receive fasteners to penetrate a pair of corresponding spacers  38 . The spacers  38  form a clearance above the baseplate  42  for operation of the mount  39 . 
     A cover  44  or cover plate  44  may include a pair of apertures at or near opposing edges thereof to receive the same fasteners that penetrate the baseplate  42 . Accordingly, the cover plate  44 , or simply cover  44 , is spaced away from the baseplate  42  sufficient distance to receive the mount  39  and attached blades  40  therewithin. Thus, the blade assembly  39  or mount  39  with its attached blades  40  is effectively “garaged” between the baseplate  42 , and the cover plate  44 . Meanwhile, a compression spring  46  pushes against the base of the T-shaped mount  39 , driving the aperture therein along the guide rod  36  captured in the aperture. 
     A reactor  20  may include a principal containment vessel  50 . In one embodiment, a conventional “tin,” or metal can, may be formed by conventional technology available for canning. In other embodiments, the reactor  20  may rely on other structures such as fiber-reinforced composites, cylinders, sealed and flexible but inextensible lattice work, fabrics, or the like, in order to contain the chemical constituents reacting to form nitric oxide. 
     In one embodiment, tablets, granules, or other configurations of reactants may be placed in a can, sealed to form the reactor vessel  50 . An aperture  40  in the vessel  50  may receive a tube  52  acting as a reactor outlet  19 . The outlet  19  may conduct nitric oxide generated within the containment vessel  50  to a location outside the insulated container  26  in order to deliver to a line  15 . 
     Various mechanisms may be available for maintaining the integrity of the apparatus  10 . In one embodiment, a heat shrinkable wrapping material may be formed in a seamless sleeve. The sleeve may be placed around the apparatus  10 , and judiciously penetrated to accommodate the fitting  14 , the vent  18 , the trigger  16 , and so forth. Thereupon, the sleeve  54  may be heated in order to shrink it snugly about the insulated container  26 . Thereafter, any breach of the sleeve  54  indicates a lack of integrity of the apparatus  10 . 
     One embodiment of an apparatus  10  in accordance with the invention was formed using expanded polystyrene for the insulated container  26 . A fitting  14  to receive a line  15  delivering nitric oxide to a cannula  56  received nitric oxide from a reactor  20  within the insulated container  26 . A vent  18  penetrated the cover  32  of the insulated container  26  to vent steam. A trigger mechanism  16  penetrated the cover  32  in order to reach the piercing assembly  30  described hereinabove. 
     Containers  28  filled with salt water were provided and placed above the piercing assembly  30  and the reactor  20  therebelow. The heaters  22  were placed entirely below the reactor  20 , although they may also be wrapped therearound, or even placed on top. However, inasmuch as the heaters  22  tend to vaporize some of the liquid in the containers  28  when released, the heated steam generated below the reactor was effective to heat the reactor  20 . Steam rising from heaters thereabove would not ever be in contact with the heaters  22 . That is, heat rising with steam originating above the reactor  20 , will not contribute as much heat to the reactor  20 . The outlet  14  from the reactor was formed of a stainless steel tube  52  penetrating the reactor  20 . 
     The blades  40  were positioned between the baseplate  42 , and the cover plate  44 . The guide rod  36  was secured to the baseplate  42  to maintain alignment of the mount  39  as the spring  46  drove the mount  39  forward along the guide rod  36 . Upon release of a trigger  16 , the mount  39  advanced out from under the cover plate  44 , exposing the containers  28  to the sharp blades  40 . The blades  40  compromised the containers  28  from below, thus substantially evacuating all the water therefrom. In the experiment illustrated, salt water was used as the liquid within the containers  28 . In some experiments, a single container was used. In other embodiments, including experiments conducted, multiple containers  28  filled with liquid were used. 
     In one embodiment, a method of producing nitric oxide may comprise the following steps. A mixture of reactants may be provided consisting essentially of potassium nitrate, sodium nitrite, and chromic oxide. The chromic oxide may be calcined to remove substantially all water bonded thereto. The reactants may be placed in a vessel, or reactor, and any moisture in the vessel may be substantially evacuated. The reactants in the vessel may be heated to a temperature selected to initiate a reaction generating nitric oxide gas. The nitric oxide gas generated may be drawn from the vessel at negative gauge pressure to substantially preclude further heating and limit further reaction, or any secondary reactions, of the nitric oxide gas. The nitric oxide gas may be cooled and mixed with a diluent gas to form a mixture breathable by a subject. The breathable mixture may be regulated to substantially ambient temperature and pressure and delivered to the subject to provide a therapeutically safe and effective concentration of nitric oxide gas. 
     Referring to  FIG. 31 , in one set of experiments, a single standard heater was used with water, as indicated. In other experiments, multiple heaters  22  were used. In yet other experiments, a single heater was used, but the liquid used to activate the heater  22 , was salt water. The chart illustrates the substantial temperature increase due to the use of the ionized salt within the salt water. Throughout the course of the experiment, the temperature was observably higher, and in some instances substantially higher, when salt water was the electrolyte initiating the reaction in the heaters  22 . Moreover, a single heater provided more temperature rise in the reactor  20  than twice that amount of chemical (two standard heaters), relying only on water alone as the electrolyte. 
     Referring to  FIG. 32 , one may see that the insulation value of the insulated container  26  has some effect. Nevertheless, in general, a more pronounced effect over the latter part of the subject time results from the addition of a second heater  22 . 
     Referring to  FIG. 33 , in another experiment, the drop off over the subject time period is more pronounced in the last half of the time. Meanwhile, the reactor temperature is maintained close to two hundred degrees Fahrenheit for at least about 20 minutes, when two heaters are used. 
     Referring to  FIG. 34 , the volume of nitric oxide produced, cumulatively, over the operation of an apparatus  10  in accordance with the invention provided the illustrated results. In the chart, temperature was maintained for an extremely long period, considering that a therapy session may typically only require about 30 minutes of nitric oxide generation. The chart illustrates that the volumetric rate of nitric oxide generated was substantially constant, giving rise to a substantially straight slope or line in the time period from about 16 minutes to about 100 minutes. Meanwhile, although the measured temperature dropped during that time period from about two hundred degrees Fahrenheit to just over one hundred degrees Fahrenheit, nitric oxide production did not drop off substantially throughout. Nevertheless, the graph illustrates an apparent decline eventually. 
     The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Technology Classification (CPC): 1