Patent Publication Number: US-11648367-B2

Title: Airway inhalant nebulizer device

Description:
TECHNICAL FIELD 
     The present invention relates to apparatus for delivering nebulized aerosol or vapor to a patient for inhalation, e.g. for the administration of medication. 
     BACKGROUND ART 
     In U.S. Pat. No. 5,603,314, Bono describes an aerosol inhalation device for delivering aerosol mist to a patient. The device comprises a nebulizer that generates and delivers an aerosol through a first conduit to the patient, and a filter that captures exhaled droplets received through a second conduit from the patient before passing now contaminant-free gas to an exhaust port. 
     In U.S. Patent Application Publication No. 2005/0263150, Chathampally et al. describes a system for administration of medications to a patient via a nebulizer in combination with an airtight face mask. The nebulizer, which is either an ultrasonic nebulizer or a jet nebulizer, produces a mist of medication-containing droplets. The nebulizer is connected to the face mask at a first one-way valve. A filtration unit, connected to the face mask at a second one-way valve, scavenges medications that would otherwise escape into the patient&#39;s immediate surroundings. 
     SUMMARY DISCLOSURE 
     A nebulizer or vaporizer device is equipped with several one-way check valves at key locations to prevent loss or spillage of fluid contained within a liquid reservoir of the nebulizer until required to be inhaled as aerosol or vapor by a user. The nebulizer chamber is equipped with an inlet port leading through a check valve and Venturi nozzle arranged to direct an air stream across an opening in the fluid flow path. In one embodiment, the check valve and Venturi nozzle together comprise a duckbill valve, which may be provided with ribs parallel to airflow within a throat of the valve/nozzle and with a thicker ring of rigid material around exit lips of the duckbill valve. When the liquid reservoir is a substantially sealed cartridge, an air intake into the liquid reservoir admits air from the nebulizer chamber to replace the fluid drawn through the fluid flow path to avoid vacuum lock between the reservoir and chamber. Both the reservoir&#39;s air intake and the fluid flow path have one-way check valves to prevent leakage of liquid if the device were to be inverted. 
     Additionally, a fluid flow path between the reservoir and the device&#39;s nebulization chamber may be heated by multiple discrete heating elements t at can be provided around that flow path. The fluid flow path may contain thermally conductive mesh at least at locations inwardly adjacent to the discrete heating elements to better transfer heat toward the center of the flow path, and wicking material may be packed between the mesh. This heating can be provided to raise the temperature of the fluid to a comfortable body temperature (e g. 37° C.) or to a temperature selected to reduce vapor pressure and thereby enhance nebulization efficiency, or even to fully vaporize the fluid if the material is sufficiently volatile that it would not be too hot for safe inhalation. To protect the contents of the liquid reservoir, thermal insulation may be provided both between and radially outward around the heating elements. 
     There are basically three main types of embodiment, a pure nebulizer, a hybrid nebulizer, and a pure vaporizer. In the pure nebulizer, a source of highly pressurized air (from a pump or compressed air source) passes over a small Venturi nozzle at the opening or tip of the fluid flow path to nebulize liquid material drawn up through the flow path from a reservoir or cartridge. In a hybrid nebulizer, heating elements are provided around the fluid flow path to apply enough heat to lower the vapor pressure in the flow path so that effective nebulization is possible with liquids that would not otherwise be possible to nebulize, or to reduce the needed velocity of the air stream passing over the opening to cause the nebulization. In a pure vaporizer, enough heat could be added to vaporize the liquid material in the flow path so that nebulization by a high velocity air stream is not even necessary. In that case, the air stream simply serves to mix with the vapor and direct the mixture out of the chamber to the user. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is side perspective view of a manually operated nebulizer device in accord with the present invention. 
         FIGS.  2  and  3    are two different perspective views from above of a second embodiment of a nebulizer in accord with the present invention. 
         FIG.  4    is a side elevational view of the second embodiment of  FIGS.  2  and  3   . 
         FIG.  5    is a partial open perspective view of the nebulization chamber in the embodiment of  FIGS.  2  through  4   . 
         FIG.  6    is a perspective view from above of a third embodiment of a nebulizer (or vaporizer) in accord with present invention that includes heating elements. 
         FIG.  7    is a perspective view of a liquid reservoir cartridge for use with any of the embodiments of the present invention. 
         FIGS.  8  and  9    are respective top plan and side perspective views of the third embodiment of the present invention. 
         FIG.  10 A  is a perspective view of liquid reservoir cartridge with a readable barcode or punch code. That code could provide information to a heater control circuit, such as optimal heating parameters (temperature, etc.) for the multiple discrete heating elements of the third embodiment, as well as manufacturer lot number, and authorization codes to prevent use of unapproved cartridges or reuse of refilled cartridges. 
         FIG.  10 B  is a perspective view of a liquid reservoir cartridge with a readable and writable RFID tag to provide the heater control circuit with the same kinds of information as the cartridge in  FIG.  10 A . 
         FIGS.  11  and  12    are side sectional views of heated fluid flow paths for the third embodiment of the present invention, the first version in  FIG.  11    using solid heating rings and the second version in  FIG.  12    using heating coils. 
         FIGS.  13  and  14    are two different perspective cutaway views of the heated fluid flow paths for the third embodiment, which include a ball valve therein. 
         FIGS.  15  and  16 A  are respective side sectional views of two versions of a check valve and Venturi nozzle combination on an inlet port to any of the embodiments of the present invention.  FIG.  16 B  is sectional view of the nozzle taken along the line  16 B- 16 B in  FIG.  16 A . 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIG.  1   , a first embodiment of a nebulizer device in accord with the present invention comprises a nebulization chamber  11  with a liquid reservoir  13  connected via a fluid flow path  12  to the nebulization chamber  11 , an inlet port and check valve  15  leading into the nebulization chamber  11  to provide a flow of accelerated air, in this case by means of a manually operated squeeze bulb  17 , a discharge port  19  for aerosolized liquid leading through an air pathway into a user mask  21 , and a filtered outlet port  23  from the user mask  21  for exhaled air, where the filter is contained within the enlarged volume  25 . A check valve  26  in the outlet flow path prevents air being drawn in from the discharge side during inhalation. Internal features of the nebulization chamber  11  and of the various connecting pathways and ports are essentially as described below in more detail for the other embodiments, in that various one-way check valves are provided for the ports or pathways to minimize or eliminate any leakage of active liquid material and to ensure that the inhaled and exhaled air flow through the proper pathways, and in that accelerated air is directed across the opening of the fluid flow path  12  leading from the liquid reservoir to cause nebulization into an aerosol that can be inhaled by an patient through the mask  21 . The mask  21  is sealed to ensure that inhaled material does not escape into the external environment. A mouthpiece or nasal canula could also be used instead of the mask  21 . 
     Instead of a squeeze bulb  17  to move air through the nebulization chamber  11 , a hand or foot operated bellows could be provided, or a small gas canister, or (as in other embodiments described below) a pressurized air supply line. All these sources of accelerated air flow are functionally equivalent, and except perhaps for different sizes and proportions of internal features of the nebulization chamber  11  to ensure adequate flow velocity and efficient nebulization are substantially identical. 
     With reference to  FIGS.  2 - 5   , another embodiment of a nebulizer in accord with the invention illustrates in more detail a version of the internal components of a nebulization chamber  31 . As in  FIG.  1   , there is a discharge port  34  leading from the chamber  31  through an air pathway  35  to a user mask, mouthpiece, or nasal cannula (not shown). A check valve  38  is provided for one-way flow of aerosol material from the discharge port  34  toward that mask. Likewise, there is an outlet port  36  containing a filter  37  (such as a HEPA filter or an activated charcoal filter), again with a check valve  39  providing one-way flow of exhaled air from the user mask to the outlet port  36 . 
     In this embodiment, the bottom of the nebulization chamber  31  forms a liquid reservoir  30 . A fluid flow path  32  extends from near the bottom of the reservoir  30  upwards to an opening  40 . An inlet port  41  coupled to an external air supply leads through a check valve  42  and a Venturi nozzle  43  that directs a stream of accelerated air across the opening  40  of the fluid flow path  32 . The nebulization device works with a non-pressurized air supply at atmospheric pressure, but a pressurized air supply could also be used, e.g. to assist those patients that have a compromised respiratory system. The check valve  42  serves mainly to prevent liquid in the chamber from leaking out in the event the nebulizer is tipped over. 
     Pressurized air source  33  provides high velocity air over the fluid path opening  40  to form very small droplets or mist. A stream of air enters through the inlet port  41  and is accelerated to high velocity by the Venturi nozzle  43 . The high velocity air stream from the nozzle  43  carries the aerosolized material out of the chamber  31  through the discharge port  34  and to the user mask. 
     With reference to  FIG.  6   , another embodiment of a nebulizer in accord with the present invention, which may be either a hybrid (heat-assisted) nebulizer or a pure vaporizer device  51  (depending upon the liquid material and the amount of heating), features a heating system  71  around the fluid flow path  54  that applies heat to material drawn from the liquid reservoir  55  and flowing within the flow path  54 . In the case of a hybrid nebulizer, the heating system  71  applies heat to the liquid in the flow path  54  to lower the vapor pressure so that nebulization can be effectively achieved with liquid materials that would not otherwise be possible with pure nebulizers as in  FIGS.  1 - 5   . In the case of a pure vaporizer, as opposed to a pure nebulizer or a hybrid (heat-assisted) nebulizer, enough heating could be applied to the liquid drawn from the reservoir sufficient to create a vapor in the fluid flow path. In that case, nebulization of the now already vaporized material is not necessary, so that neither a highly pressurized air supply path (from a pump or compressed source) nor a high-velocity air stream is required. In that case, the air stream from the nozzle  62  is merely provided to mix with the vaporized material and help direct that mixture out of the chamber  53  to a user. 
     Also, the liquid reservoir can be provided in the form of an attachable reservoir cartridge  55 , instead of simply storing the liquid at the bottom of the chamber  53 . Not only does this prevent sloshing of liquid about the chamber  53  but, in the case of heated devices like that shown in  FIG.  6   , more effectively isolates the liquid material from unnecessary heating until it is drawn up through the flow path  54 . The bottom  52  of the chamber  53  can be detached to allow insertion of a new cartridge  55  therein. As seen also in  FIG.  7   , the cartridge  55  may have a set of check valves  56  and  57  that can prevent leakage of liquid from the reservoir  55  in the event the cartridge were to be tilted or inverted, while still allowing adequate flow of liquid material into a fluid flow path  54  and admission of replacement air into the cartridge  55  to prevent vacuum lock. 
     As in the previous embodiments, and as also seen in  FIGS.  8  and  9   , an inlet port  61  with check valve and Venturi nozzle  62  produces a high velocity airstream for carrying nebulized material drawn from the reservoir cartridge  55  out of fluid flow path opening  40  and nebulized by pressurized air source  33  in  FIG.  8   , or alternatively for carrying vaporized material drawn from the reservoir cartridge  55  out of the top vaporizer opening  63  of the heated fluid pathway  54  in  FIG.  9   . 
     The one-way check valve and Venturi nozzle  62  may together comprise a duckbill valve, which is an option for any of the embodiments and will be discussed further below. An air intake  59  admits air from the top, sides or bottom of the chamber  53  and into the cartridge  55  through the check valve  57 . A discharge port  64  exits the chamber  53  and leads through a check valve  65  and an air pathway  66  to a user mask (not shown). Exhaled air is directed from the user mask through the air pathway  66  and check valve  67  to a filter  68  and outlet port  69 . 
     As seen in  FIG.  6    (but also in more detail in  FIGS.  11  to  14   , discussed further below), multiple discrete heating elements  71  are spaced around the fluid flow path  54 . In this way, the liquid drawn up through the flow path  54  may be heated prior to nebulization at the top opening  63 . The liquid could be heated, e.g., close to normal human body temperature (37° C.) to ease the body&#39;s response to the aerosol being inhaled into the lungs. This reduces the chances of lung spasms in response to inhaling a cold aerosol mist, facilitates better bio-uptake of the intended medicinal material in the lungs (e.g. the body responds better to certain anesthetics if they are at body temperature), and more generally increases user comfort. Note that the Venturi effect itself causes the airstream to chill as it is accelerated by the nozzle  62  and then directed across the opening  63 , so preheating of the liquid drawn through the flow path  54  is beneficial to restoring a more useful and comfortable temperature. Still further, heating of the liquid reduces the vapor pressure and thereby enhances nebulization efficiency. Finally, assuming the liquid material is adequately volatile, so that overly hot temperatures are not required, the heating can actually vaporize the material as it is drawn up through the flow path  54  for mixing with the airstream from the nozzle  62 . It could then subsequently re-condense into an aerosol mixture as it interacts with the airstream and cools. 
     Since the heating elements require electricity and corresponding electrical and thermal control, inlet ports for the electrical pathways will be provided. A lithium ion battery pack  73  could supply the electrical power for the controlled heating, as seen in  FIGS.  8  and  9   , where for example the battery pack  73  is conveniently attached to the inlet port  61 . A control circuit board  75  and a thumb activated trigger switch  77  (in some embodiments including a fingerprint sensor to prevent unauthorized use) could likewise be attached at any convenient location on the exterior of the device. In some embodiments the control circuit board  77  could require activation of the user&#39;s authorized fingerprint at a point-of-sale location or other location approved to verify the user&#39;s government issued ID. This would serve to prevent device usage by underaged or non-prescription users. 
     In one possible embodiment, a readable barcode or punch code  71  can be provided on the cartridge, for example on its edge as seen in  FIG.  10 A , to provide a variety of information specific to the cartridge contents to the heater control  75 . This can include heating parameters for the liquid material (such as specific heating zones or profiles of the discrete heating elements around the flow path, maximum temperatures, etc.). 
     In yet another embodiment, as seen in  FIG.  10 B , an RFID tag  72  could be included in the cartridge. The nebulizer&#39;s or vaporizer&#39;s heater control circuit could write to the RFID tag  72  via micro-USB, Bluetooth/WIFI connectivity, or other communication means to record cartridge information updates. Hence, the RFID tag  72  would not only allow storage of much the same kinds of coded information content as the barcode (e.g. specific parameters for heating the cartridge&#39;s liquid contents along the flow path) but could also log new information (such as the number of times the cartridge is used or whenever it becomes empty) to prevent unauthorized refilling of a cartridge. Stored information can include manufacturer authorization and batch codes, whereby a heater control circuit could activate a “limp mode” to prevent heating of unknown or adulterated contents. If the RFID coded information does not match manufacturer specifications (e.g. with a cartridge forgery), or the number of recorded uses exceeds some specified reasonable limit, or the cartridge has previously been empty but not refilled by the manufacturer itself, but by some unknown third party, then for user safety the nebulizer or vaporizer, responsive to the RFID coded information could refuse to operate. 
     With reference to  FIGS.  11 - 14   , multiple discrete heating elements  81  (in this instance, two) surround the core of the fluid pathway  80  to provide gradated levels of heating. The heating elements  81  may be foil or solid rings or could be heating coils  181  as seen in  FIGS.  12 - 14   . Spacing  82  between the heating elements  81  reduces heat-soak between elements. An insulating outer liner  83  of ceramic, polyimide or other thermal insulation material may be provided to prevent heat transference into the fluid reservoir itself or into the duckbill valve or other Venturi nozzle where excess heating could cause damage. Only the fluid flow path  80  and the liquid within it should be heated by the elements  81 . A liner  84  may be disposed between the heating elements  81  and the flow path  80 . This inner liner  84  can serve as a thermal conductor (e.g. stainless steel) or as an insulator (e.g. ceramic or polyimide) depending on specific design intent (e.g., some portions of the liner along the length of the pathway  80  may be conductive and other portions may be insulative to precisely control where the heat is to be transferred into the liquid material, while keeping the liquid in the reservoir cool). Heating mesh  85  is in the fluid path  80  to conduct heat from the liner wall  84  into the center of the flow path  80 . This added thermal conductivity removes any need to overheat the liquid along the wall  84  of the passage  80  to compensate for cooler liquid passage along the center of the passage  80 . The mesh  85  could instead be in the form of a lattice, coils or filamentary material. It is anticipated that wicking material  86 , commonly used in standard vaporizers, could be packed between the heat-conducting mesh/lattice/coils/filaments to assist moving the fluid up through the pathway  80 . Since the inner liner  84 , the mesh  85 , and wicking material  86  are in contact with the liquid material to be nebulized and inhaled by a patient, they will need to be composed of bio-compatible materials to avoid any cross-contamination. 
     As seen in  FIGS.  13  and  14   , a ball valve  88  may be part of the fluid supply pathway  80 . A weighted ball normally resting one of the conducting mesh elements  85  to allow fluid to pass around the ball, will engage a sealing surface  89  if the device is inverted to prevent leakage of liquid out of the reservoir and flow path. A similar ball valve may also be included in the air return tube. An added advantage to having the ball valve in a heated nebulizer (or vaporization) device is that the ball  88  will be pushed upwards against sealing surface  89  if vapor flow is very strong and therefore act as a check against too hot material from being inhaled and burning the mouth, throat or lungs of a patient. 
     With reference to  FIGS.  15  and  16 A , two versions of the check valve and Venturi nozzle are shown. In  FIG.  15   , a check valve  91  and Venturi nozzle  92  are separate components and the Venturi nozzle  92 , while serving as a partial check valve, is mainly provided for its acceleration of the incoming airstream into a directed high velocity stream across the top opening  95  of the fluid flow path  93 . Since some liquid could leak through the nozzle  92  if the device is tilted, the check valve  91  is provided to block any liquid from splashing out of the nebulizer device. Alternatively, in  FIG.  16 A , the check valve and Venturi nozzle are combined into a single duckbill check valve  96  whose beak  97  has a sufficiently narrow opening that liquid cannot substantially leak out. The duckbill valve  96  is shaped to serve the dual function as a nozzle that accelerates airflow over the supply pathway&#39;s opening. It has a nozzle shape to create a Venturi effect on air flowing through it. To enhance its performance, a set of ribs  99  parallel to the airflow may be provided on the interior throat or bill of the valve  96  to ensure laminar flow toward the beak opening, as seen in the  FIG.  16 B  cross-section. Additionally, the beak opening  97  of the valve  96  may, in some cases, be thickened to form a ring of material around the opening  97  that will maintain the widened shape of the opening to create the ribbon of accelerated laminar-flow air (rather than stretching into an annular shape) as well as make it more rigid and avoid any vibratory opening and shutting of the opening.