Abstract:
An aerosol medication delivery apparatus includes a fixed volume holding chamber which is constructed to allow for a uniformly mixed, concentrated bolus of medicated aerosol to be delivered with each breath. The device further includes a universal inlet, so that any standard small volume nebulizer, as well as any standard metered dose inhaler (MDI), may be utilized therewith. Also filtration can be added to address contaminated patient air and aerosol. A one-way valve is positioned between the holding chamber and a tee piece for attaching the holding chamber to a patient mouthpiece, to help control the loss of aerosol, and thereby reduce waste. The device is simply constructed of two molded plastic members, which are readily engaged to complete its assembly.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to an improved aerosol inhalation device, and more particularly to an aerosol enhancement device which is usable in combination with both a nebulizer and a metered dose inhaler. 
     Aerosol inhalation devices, for the purpose of delivering medication, entrained in an aerosol spray, to a patient using inhalation therapy, as an alternative to oral medications such as capsules or pills, or to injected medications, are well known in the art. For example, U.S. Pat. No. 4,210,155 to Grimes is representative of the prior art. In the Grimes patent there is disclosed a fixed volume mist accumulation chamber for use in combination with a nebulizer and a tee connection of an inhalation conduit for accumulating medicated mist and facilitating its delivery to a patient. 
     However, the Grimes device, as is typical for prior art devices, is plagued with problems typical of such devices. These problems include, for example, non-uniform concentrations of medication, resulting in difficulties in regulating patient dosage, and significant waste of medication. Additionally, the Grimes device is relatively complex, so that it is expensive to manufacture and difficult to use. 
     Many other such devices are available which do not include a mixing chamber. In other words, the nebulizer is attached directly to the aforementioned tee connection. Of course, such devices are even less suited to satisfactory regulation of the medication being delivered to the patient than the Grimes device, because there is substantially no ability to uniformly mix the medication with entrained fluid, such as air, before delivery to the mouthpiece on which the patient is inhaling. 
     In addition to nebulizers, metered dose inhalers (MDI) are also available for delivering a medicated aerosol to a patient. These MDI devices differ from nebulizers primarily in that a propellant is used to deliver the medication. 
     It would be advantageous to have an aerosol medication delivery device which included a mixing chamber between the medication delivery apparatus and the mouthpiece, wherein the medication could be uniformly mixed with entrained air in an improved manner over that achieved by the Grimes patent apparatus. It would also be beneficial for such a device to be simple to manufacture and assemble, and easy to use. Finally, if such a device could be made universally adaptable for use with any known nebulizer on the market, as well as with MDI&#39;s, this would be a great advance in the art. 
     SUMMARY OF THE INVENTION 
     The present invention provides an aerosol medication delivery apparatus which incorporates the aforementioned advantages. The inventive device includes a fixed volume holding chamber which is constructed to allow for a uniformly mixed, concentrated bolus of medicated aerosol to be delivered with each breath. The device further includes a universal inlet, so that any standard small volume nebulizer, as well as any standard MDI, may be utilized therewith. Also filtration can be added to address contaminated patient air and aerosol. A one-way valve is positioned between the holding chamber and a tee piece for attaching the holding chamber to a patient mouthpiece, to help control the loss of aerosol, and thereby reduce waste. The device is simply constructed of two molded plastic members, which are readily engaged to complete its assembly. 
     More particularly, an aerosol enhancement device is provided which comprises a mouthpiece and a tower member fluidly attached to the mouthpiece. The tower member has an outer body which defines an interior volume, together with an inner wall disposed in the outer body. The inner wall extends a substantial distance through the interior volume and defines a holding chamber interiorly of the inner wall. An annular air passage is defined between the inner wall and the outer body. An inlet port is disposed in the tower member for receiving a medicated aerosol from an exterior source into the holding chamber. An air inlet port is disposed in the tower member, as well, for receiving air into the air passage. Advantageously, because of the lengthy inner wall, which may preferably comprise a tubular member, so that the resultant defined air passage is annular, the air in the air passage flows around said inner wall and into holding chamber, to be entrained with the medicated aerosol for a sufficient distance as it travels through the holding chamber to ensure thorough mixing. 
     A further innovation in the aforementioned device is the employment of a T-piece for attachment of the tower member to the mouthpiece, and the incorporation of a one-way valve in the T-piece for preventing medication waste. A one-way valve, preferably comprising an O-ring valve, is preferably disposed in the air inlet port, as well. 
     In another aspect of the invention, an aerosol enhancement device is provided which comprises a mouthpiece and a tower member fluidly attached to the mouthpiece. The tower member has an outer body which defines an interior volume. An inlet port is disposed in the tower member for receiving a medicated aerosol from an exterior source into the interior volume. Advantageously, an adapter is disposed in the medicated aerosol inlet port. The inventive adapter comprises a universal fitting which is capable of attaching the tower member to either a nebulizer or a metered dose inhaler (MDI). 
     Preferably, the inventive adapter is reversible, being disposable in a first orientation for attachment of the tower member to a nebulizer, and being disposable in a second orientation for attachment of the tower member to an MDI. In its preferred configuration, the universal adapter comprises a first rigid connector end and a second flexible connector end, the first rigid connector end being adapted for attachment to a nebulizer and the second flexible connector end being adapted for attachment to an MDI. The adapter preferably further comprises a flange portion for engaging the adapter with the tower member. 
     In still another aspect of the invention, an aerosol enhancement device is provided which comprises a mouthpiece and a T-piece attached to the mouthpiece. The T-piece has a first port for attachment to the mouthpiece, a second port which is open to atmosphere, and a third port. A medication dispenser is attached to the third port, and, advantageously, an exhalation filter is disposed in the second port. 
     In yet another aspect of the invention, a tower member is provided which is usable with a mouthpiece, for dispensing medicated aerosol to a patient. The inventive tower member comprises an outer body which defines an interior volume, and an an inner wall disposed in the outer body. The inner wall extends a substantial distance through the interior volume and defines a holding chamber which is disposed interiorly of the inner wall. The inner wall and the outer body define an air passage therebetween. An inlet port is disposed in the tower member for receiving a medicated aerosol from an exterior source, such as a nebulizer or MDI, into the holding chamber, and an air inlet port is disposed in the tower member for receiving air into the air passage. An outlet port for dispensing medicated aerosol entrained in air from the holding chamber to the mouthpiece is provided as well, wherein the air in the air passage flows therethrough around the inner wall and into the holding chamber, to be entrained with the medicated aerosol. 
     In another aspect of the invention, there is provided a tower member usable with a mouthpiece, for dispensing medicated aerosol to a patient. The tower member comprises an outer body which defines an interior volume, and an inlet port disposed in the tower member outer body for receiving a medicated aerosol from an exterior source into the interior volume. An adapter is disposed in the medicated aerosol inlet port. The adapter comprises a universal fitting which is advantageously capable of attaching the tower member to either a nebulizer or a metered dose inhaler (MDI). 
     In yet another aspect of the invention, there is provided a tower member usable with a mouthpiece, for dispensing medicated aerosol to a patient. The tower member comprises a first member comprising a fitting for attachment of the tower member to the mouthpiece and a disk having an air inlet port disposed therein, as well as a second member comprising an outer body which defines an interior volume and an inlet port disposed in the tower member outer body for receiving a medicated aerosol from an exterior source into the interior volume. Advantageously, a medicated aerosol delivery device is easily assembled by engaging the first and second members to form the aforementioned tower member. 
     In still another aspect of the invention, there is provided a tower member usable with a mouthpiece, for dispensing medicated aerosol to a patient. The tower member comprises an outer body which defines an interior volume, and an inlet port disposed in the tower member outer body for receiving a medicated aerosol from an exterior source, which is preferably a nebulizer, into the interior volume. An adapter is disposed in the medicated aerosol inlet port, and comprises a fitting which is capable of attaching the tower member to the exterior source. Advantageously, a drainage channel, and preferably four spaced drainage channels, is/are disposed near a joint between the fitting and the outer body for draining liquid from the interior volume into the exterior source. 
     The invention, together with additional features and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying illustrative drawing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side plan view of one embodiment of the inventive aerosol enhancement device; 
     FIG. 2 is a perspective view of the top portion of the two-piece holding chamber which forms a part of the aerosol enhancement device illustrated in FIG. 1; 
     FIG. 3 is a perspective view of the bottom portion of the two-piece holding chamber which forms a part of the aerosol enhancement device illustrated in FIG. 1; 
     FIG. 4 is a side plan view of the holding chamber of a modified embodiment of the inventive aerosol enhancement device; 
     FIG. 5 is a side plan view of a reversible fitting, in isolation, which forms a portion of the holding chamber illustrated in FIG. 4, which in one orientation adapts the holding chamber for attachment to a nebulizer, and in a second orientation adapts the holding chamber for attachment to a metered dose inhaler; 
     FIG. 6 is a side plan view of the reversible fitting illustrated in FIG. 5, attached to a nebulizer; 
     FIG. 7 is a side plan view of the reversible fitting illustrated in FIG. 5, attached to a metered dose inhaler; 
     FIG. 8 is a side plan view of an entire inhalation system constructed in accordance with the principles of the present invention, wherein the holding chamber is attached to a nebulizer; 
     FIG. 9 is a side plan view of an entire inhalation system constructed in accordance with the principles of the present invention, wherein the holding chamber is attached to a metered dose inhaler; 
     FIG. 10 is a top view of a third modified embodiment of the inventive aerosol enhancement device; 
     FIG. 11 is a cross-sectional view taken along lines  11 — 11  in FIG. 10; and 
     FIG. 12 is a cross-sectional view similar to that of FIG. 11, wherein the reversible fitting is shown in its alternate orientation. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now more particularly to FIGS. 1-3, there is shown a first embodiment of the inventive aerosol enhancement device  10 . The device  10  comprises a mouthpiece  12  which is fluidly connected with a T-piece  14 . The T-piece  14  is, in turn, attached to a tower  16 . The tower  16  comprises an outer body  18  and inner tubing  20 . As will be described in more detail below, air is entrained into the outer body  18  through air inlet ports  22 , as shown by arrows  24 , traveling through an annular passage  26  which is defined by the outer walls of the tower  16  and the inner tubing  20 . When the air reaches the lower edge of the inner tubing  20 , it reverses direction and travels upwardly into a holding chamber  28 , which is defined by the inner tubing  20 . A lower inlet port  30  supplies a medicated aerosol, as shown by arrow  32 , into the holding chamber  28 , which functions as a mixing zone for mixing the incoming medication with the incoming air. 
     As noted supra, the purpose for the holding chamber  28  is to thoroughly mix the incoming medication and air together, which occurs as the two components flow upwardly together, in turbulent fashion, through the holding chamber  28 , as shown by arrow  34 . Once thoroughly mixed, the medicated mixture flows into the T-piece  14 , and then into the mouthpiece  12  for inhalation by a patient, as shown by arrows  35 . 
     A valve, preferably an o-ring valve  36 , controls the air inflow through each air inlet port  22 , in a manner to be described more fully below, as shown in FIG. 1. A second check valve  37  is preferably disposed in the vicinity of the fitting  40 , between the chamber  28  and the T-piece  14 , for the purpose of controlling the loss of aerosol. 
     Referring now particularly to FIGS. 2 and 3, it is apparent that the outer body  18  is preferably formed as a single piece with the lower inlet port  30  (FIG.  3 ). Additionally, the inner tube  20  is preferably formed as a single piece  38  with a disk  39  which includes a plurality of the air inlet ports  22 , together with a fitting  40  for attachment to the T-piece  14 . The two pieces  18  and  38  are engaged by inserting the single piece  38  into the outer body  18 , as shown in FIG. 1, to form the device  10 . 
     Now with reference to FIGS. 4-9, a modified embodiment of the inventive device is illustrated, wherein like elements are designated by like reference numerals, preceded by the numeral  1 . In this embodiment, the construction of the device  110  is similar to that of the device  10  in FIGS. 1-3, except for the employment of a reversible fitting or adapter  142  in place of the fixed inlet port  30  in the prior embodiment. The adaptive fitting  142  includes an engagement flange  144 , a rigid connector end  146 , and a flexible connector end  148 . The flexible connector end  148  is preferably in the nature of a boot, fabricated of a soft pliable material, such as Neoprene, while the engagement flange  144  and rigid connector end  146  are preferably fabricated of a rigid molded plastic, such as ABS, which may be the same material that is used to fabricate the remainder of the device. An injection molding process may be used to mold the device, if desired. 
     The purpose of the adaptive fitting  142  is to permit the tower body  118  to be able to accommodate attachment of the device to both a nebulizer  150  and a Metered Dose Inhaler (MDI)  152  (see FIGS.  8  and  9 ). As is shown in FIGS. 6 and 8, the smaller, rigid connector end  146  may be used to attach the device  110  to a nebulizer  150 . On the other hand, an MDI typically has a non-round mouthpiece  154 , and therefore the inventors have found that a pliable boot connector such as connector  148  is required for a successful fit, by providing a flared access for the MDI boot, as shown in FIGS. 7 and 9. 
     The inventors have found that when the inventive apparatus is in the “nebulizer mode”, as shown in FIG. 6, for example, it is particularly advantageous to include drain channels  155  in the flexible connector end  148  of the adaptive fitting  142 . In a preferred configuration, the channels are disposed in the connector end  148 , just above the joint between the connector end and the floor of the tower  116 . Preferably, four such channels, spaced equally about the circumference of the flexible connector end  148 , are employed, though other arrangements, including a different number of channels, or an annular channel, could be employed, if desired. The purpose for the drain channels  155  is to re-capture liquid medication which may accumulate in the tower  116  as a result of incomplete entrainment of the medication in the air flow which enters the tower  116  through the air inlets  136  and advances into the holding chamber  128  for inhalation by the patient. The re-captured medication flows through the drain channels  155  back into the nebulizer  150 , where it can be administered to the patient. 
     Of course, while, for exemplary purposes, the drain channels  155  are illustrated only in the FIGS. 4-9 embodiment, such channels, or other drainage means, could be employed in any of the illustrated embodiments, or other embodiments incorporating the unique features of the present invention, as well. 
     Now with reference to FIGS. 10-12, there is shown yet another presently preferred embodiment of the inventive aerosol enhancement device. In this embodiment, wherein like elements to those of previous embodiments are designated by like reference numerals, preceded by the numeral  2 , which is substantially similar to the embodiment of FIGS. 4-9, the only substantial difference is in the employment of an end cap  256 , which includes the fitting  240  and the disk  239 . The end cap  256  is not unitary with the inner tube  220 , however, as in the preceding embodiment. Additionally, as is seen in FIGS. 11 and 12, the flexible connector end  248  is attached to the rigid connector end  246  by means of an annular flanged joint  258 . Of course, FIGS. 11 and 12 are similar, except that the reversible fitting  242  is oriented in an opposite manner in FIG. 12 with respect to its orientation in FIG. 11, for the purpose of accommodating an MDI, rather than a nebulizer. 
     Presently preferred design options include holding chamber volumes ranging from 90 cc to 140 cc, and chamber lengths ranging from 2.95 inches to 1.56 inches, depending upon the chamber volume and the internal diameter of the chamber. The total stacked height of the inventive apparatus, including an attached nebulizer, may range from 6.7 to 8.3 inches in the presently preferred embodiments, depending upon chamber volume and internal diameter. 
     In operation, in any of the illustrated embodiments, the apparatus  10  is particularly adapted for dual use applications, as noted supra. In particular, the device  10  may be utilized in conjunction with a nebulizer, wherein the tower  16 , and in particular, the holding chamber  28 , functions to recirculate medication introduced by the nebulizer, in order to provide a denser application of medication to the patient. The provided fittings are universally suitable for attachment to any known nebulizer. In an alternative configuration, wherein the device  10  is utilized in conjunction with an MDI, the tower  16  functions as a spacer, for the purpose of ensuring a more uniformly mixed dose of medication to the patient. 
     Whether The device  10 ,  110 ,  210  is being used with a nebulizer or an MDI, the purpose of the holding chamber  28  is to repeatedly capture the generated aerosol from the nebulizer or MDI into the fixed volume chamber, which allows for a concentrated bolus of medicated aerosol to be delivered with each breath taken by a patient who is breathing through the mouthpiece  12 . In the case of a nebulizer  150 , the medicated aerosol is drawn therefrom by the vacuum created by inspiration by the patient through the mouthpiece, while in the case of an MDI, a propellant injects the medicated aerosol therefrom into the chamber  28 . The inventors have advantageously found that the length of the inner holding chamber  28  in each embodiment (i.e. the length of the inner tubing  20 ) should be more than half of the length of the tower  18 , and preferably much more than half, in order to ensure adequate entrainment and mixing of the air and medicated aerosol. Though not shown, in some embodiments, a bridge adapter may be employed to adapt the device to various prior art mouthpieces. Also, the inventors have found that an exhalation filter  58  (FIG. 1) disposed in the exit end of the T-piece  14 , is useful in dealing with circumstances involving contaminated or infectious patient air and aerosol, to minimize the spread of infection. 
     The apparatus and method of 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.