Abstract:
This invention is a device ( 10 ) for inspiration of a mist from a nebulizer, the device comprising an inlet connector ( 12, 32 ) adapted to engage an outlet port of a nebulizer; a hollow mouthpiece element ( 126, 34 ) for insertion into a patient&#39;s mouth; a conduit ( 14 ) forming a fluid connection between the inlet connector, and the hollow mouthpiece element; an exhaust valve ( 26 ) for removing expiratory gases which are exhaled into the mouthpiece element to the ambient atmosphere via the exhaust/positive expiratory pressure (PEP) valve ( 26, 50 ) positioned on the conduit between the inlet connector, and the mouthpiece element; and a filter housing ( 44 ) containing a filter ( 60 ) for filtering the exhaled gases passing from the exhaust/PEP valve.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates to an improved nebulizer mouthpiece and accessories.  
         DESCRIPTION OF THE PREVIOUSLY PUBLISHED ART  
         [0002]    Our earlier U.S. Pat. No. 5,584,285, discloses a nebulizer with a mouthpiece having a flap valve  124  shown in FIG. 3 of the patent which is reproduced here as Fig. A. When the patient exhales into the mouthpiece  126  the air pressure causes the flap  124  to open and let the exhaust air out of the mouthpiece.  
           [0003]    This early design, while operational and commercially effective, is not optimal. Since the flap valve  124  is in the path of the incoming inspiration mist, there is the possibility that the mist under sufficient pressure can cause the flap to slightly open such that some of the mist will leave the mouthpiece in the form of rainout before it reaches the patient. When the patient exhales, there is no structure to direct the exhaust flow against the valve or increase back pressure to assist the valve opening. The valve only opens when the exhaust gas back pressure reaches a certain level. The flap valve is made of a stiff yet flexible material and thus it will inherently have some resistance to opening at very low pressures. If any rainout accumulates on the external surface of the flap valve, it is also difficult for the liquid material to flow back into the mouthpiece. The inner peripheral surface of the flap may stick to the overlapping external surface of the mouthpiece when the inner surface of the flap is wet.  
         OBJECTS OF THE INVENTION  
         [0004]    It is an object of this invention to provide an improved mouthpiece exhalation valve for a nebulizer or breathing circuit containing a nebulizer where the design of the internal passageway contains an offset which causes the inspiration mist flow to bypass the exhaust valve without impingement together with a filter arrangement associated with the exhaust valve and a positive expiratory pressure valve and/or a positive expiratory pressure (PEP) valve.  
         SUMMARY OF THE INVENTION  
         [0005]    According to the invention there is provided a mouthpiece device for inspiration of a mist from a nebulizer comprising: an inlet connector adapted to engage the outlet port of a nebulizer; a hollow mouthpiece element for insertion into a patient&#39;s mouth, a conduit forming a fluid connection between the inlet connector and the hollow mouthpiece element; an exhaust valve for removing exhalation gases which are exhaled into the mouthpiece element to outside the device, said exhaust valve being positioned on the conduit between the inlet connector and the mouthpiece element; and a filter housing incorporating a filter to filter exhaled gases passing from the exhaust valve.  
           [0006]    Also according to the invention there is provided a mouthpiece device for inspiration of a mist from a nebulizer comprising: an inlet connector adapted to engage the outlet port of a nebulizer; a hollow mouthpiece element for insertion into a patient&#39;s mouth, a conduit forming a fluid connection between the inlet connector and the hollow mouthpiece element; an exhaust valve for removing exhalation gases which are exhaled into the mouthpiece element to outside the device, said exhaust valve being positioned on the conduit between the inlet connector and the mouthpiece element; and a positive expiratory pressure valve is disposed to produce a back pressure in the gases exhaled through the exhaust valve.  
           [0007]    Also according to the invention, there is provided a mouthpiece device for inspiration of a mist from a nebulizer comprising: an inlet connector adapted to engage the outlet port of a nebulizer; a hollow mouthpiece element for insertion into a patient&#39;s mouth, a conduit forming a fluid connection between the inlet connector and the hollow mouthpiece element; an exhaust outlet for removing exhalation gases which are exhaled into the mouthpiece element to outside the device, said exhaust outlet being positioned on the conduit between the inlet connector and the mouthpiece element; and a positive expiratory pressure valve is disposed to produce a back pressure in the gases exhaled through the exhaust outlet.  
           [0008]    Also according to the invention there is provided a method for breathing an inspiration of a mist from a nebulizer comprising: using a mouthpiece element having an inlet connector adapted to engage the outlet port of a nebulizer; a hollow mouthpiece element for insertion into a patient&#39;s mouth; a conduit forming a fluid connection between the inlet connector and the hollow mouthpiece element; an exhaust valve positioned on the conduit between the inlet connector and the mouthpiece element for removing exhalation gases which are exhaled into the mouthpiece element to outside the device; and a filter housing incorporating a filter to filter exhaled gases passing from the exhaust valve. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    The invention will now be described, by way of example, with reference to the accompanying drawings, in which:  
         [0010]    Fig. A is a portion of an exploded side view in cross-section of a prior published mouthpiece and a portion of the nebulizer.  
         [0011]    [0011]FIG. 1 is an exploded perspective view of the mouthpiece with the valve disc and retainer ring;  
         [0012]    [0012]FIG. 2 is a cross-sectional side view of the mouthpiece;  
         [0013]    [0013]FIG. 3 is a top view of a suitable valve disc with peripheral and radial cuts;  
         [0014]    [0014]FIG. 4 is a side view of the mouthpiece without the retaining ring;  
         [0015]    [0015]FIG. 5 is a top view of the mouthpiece without the retaining ring and valve disc;  
         [0016]    [0016]FIGS. 6 a ,  6   b ,  6   c ,  6   d  illustrate various cut patterns for the valve disc;  
         [0017]    [0017]FIGS. 7 a  and  7   b  illustrate alternative valve support embodiments;  
         [0018]    [0018]FIG. 8 is an exploded side view of the mouthpiece with a partially threaded valve body and optional filter and/or an adjustable positive expiratory pressure (PEP) valve with manometer connector;  
         [0019]    [0019]FIG. 9 is a sectional side elevation of the optional PEP valve shown in FIG. 8;  
         [0020]    [0020]FIG. 10 is a top view of the PEP valve shown in FIG. 9;  
         [0021]    [0021]FIG. 11 is an perspective view from the top of the filter body shown in FIG. 8;  
         [0022]    [0022]FIG. 12 is a rear perspective view of the filter body shown in FIGS. 8 and 11;  
         [0023]    [0023]FIG. 13 is an perspective view from the bottom of the filter body shown in FIGS. 8, 11, and  12 ;  
         [0024]    [0024]FIG. 14 is a partial cross-sectional front elevation of the filter body showing a filter located in place for use;  
         [0025]    [0025]FIG. 15 is a cross-sectional side elevation of the filter body with the filter in place;  
         [0026]    [0026]FIG. 16 is a top view of the lower portion of the filter body with the filter shown hatched;  
         [0027]    [0027]FIGS. 17A and 17B are two perspective views of another embodiment of the filter housing;  
         [0028]    [0028]FIGS. 18A and 18B are two perspective views of the interiors of the top and bottom of the embodiment shown in FIG. 17; and  
         [0029]    [0029]FIGS. 19 and 20 are respectively an exploded view and a cross-sectional elevation of a different embodiment of a PEP valve. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0030]    The improved mouthpiece according to the invention will now be described by referring to FIGS.  1 - 7 . The mouthpiece  10  has a circular connector piece  12  which engages the outlet of a nebulizer in the same way that the mouthpiece engages the nebulizer in Fig. A. The opposite end of this mouthpiece device is the mouth shaped end piece  14  that, in use, is placed in the patient&#39;s mouth. On top is a valve disc housing  16  that holds the exhaust valve for exhausting the exhalation from a patient. In the exploded view of FIG. 1, the valve housing  16  contains an inner ring  18  the base which serves as a support ring for the valve disc. In the embodiment illustrated there is a central hub  20  which is supported by three arms  22 . These arms are quite thin so that the open areas  24  between them represent a substantial portion of the cross-sectional area in the housing. Other configurations and different numbers of arms can be used. Above the housing in the exploded view is the valve disc  26  sized fit on top of the arms and the support ring  18 . The arms  22  and hub  20  prevent the valve disc  26  from opening inwardly during inhalation. Above the valve disc in the exploded view is a retainer ring  28  having the outer wall shown and an inner wall (not shown) which is of slightly smaller diameter. The outer wall screw threads over threads  30  of the valve housing wall  16  to hold the outer peripheral area of the valve disc in place, by means of the inner wall, when the unit is assembled. The retaining ring  28  has a series of projections or ribs to facilitate gripping the ring and twisting it off the threads  30  for removal.  
         [0031]    [0031]FIG. 2 is a cross-sectional side view of the mouthpiece device showing the elevational relationship of the parts and passageways. For greater clarity, the retaining ring  28  and the valve disc have been removed. The circular connector  12  will fit into the conventional circular outlet port of nebulizer. The mouth shaped end piece  14  at the other end is positioned above the center line of the circular connector  12 . The back wall  13  of the connector  12  joins the connector to the upper mouthpiece. The valve housing  16  is part of the mouth shaped end piece  14 . Inside the housing the support ring  18  together with the hub  20  and support arms  22  are arranged to support the valve disc  26 .  
         [0032]    When the mouthpiece is used by a patient, inspiration mist enters the circular connector  12  through its opening  32  and passes through the device and out the opening  34  in the mouthpiece. In that flow path inside the circular connector  12  is a deflector  36  which extends out at an obtuse angle from the inside wall of the circular connector  12  toward opening  34 . The purpose of the deflector is two fold. First, with regard to the incoming inspiration mist, the deflector deflects that gas stream away from the valve disc in the valve housing so that the mist will not strike the valve disc and thus there is no possibility that some of the mist might leave through the valve disc. The second function is that in the respiration cycle when the patient is exhaling, the exhalation gas will be deflected so that exhalation gas is directed into the valve housing  16  where it can exhaust through the valve disc  26 .  
         [0033]    [0033]FIG. 3 is a top view of the thin valve disc  26 . The radial cuts  40  and annular cuts  42  in the valve disc facilitate draining the accumulated moisture back into the mouthpiece on inhalation. There can be many possible-cut patterns in the disc to define various flaps which will open upwardly when the exhalation pressure is applied to permit the exhalation gas to leave the mouthpiece. Seen here are three radial cuts  40  from the center and three annular cuts  42  which define six flaps  41 . As exhalation gas pressure is applied from below, these flaps will open along the cut lines to let gas escape from the mouthpiece.  
         [0034]    [0034]FIG. 4 is an outside view of the device showing again the elevational relationship between the circular connector  12 , its back wall  13  connecting to the higher level mouth shaped end piece  14 . The valve housing is made a part of the mouth shaped end piece  16  above where it connects to the circular connector.  
         [0035]    [0035]FIG. 5 is a top view of the device without the retaining ring  28  and valve disc  26 . The support structure for the valve disc  26  is made up of the ring surface  18 , the three grille arms  22  and the central hub  20 . The end of the mouth shaped piece that is placed in the patient&#39;s mouth has a greater width than the opposite end where the valve housing is located. The mouth end has an oval opening to better anatomically fit in the patient&#39;s mouth.  
         [0036]    [0036]FIG. 6 a - d  illustrate various cut patterns for the valve disc  26 . In  6   a , each of six radial cuts the center form a flap  41  on either side of the cut in conjunction with annular cuts so as to provide twelve flaps which can open up in response to the exhalation pressure. In  6   b  there are three large flaps  41  which pivot adjacent the disc center and extend toward the periphery. In  6   c  where each radial cut meets the annular cut it forms the apex for a flap. Thus here are five flaps formed in FIG. 6 c . In  6   d  each radial cut defines two flaps and so as to form six flaps formed.  
         [0037]    [0037]FIGS. 7 a ,  7   b  are plan views of alternative support means integral with the hollow mouthpiece element positioned so as to prevent the opening of the exhaust valve element during patient or user inhalation.  
         [0038]    Referring to FIG. 8, the valve body  16  is provided with interrupted threads  30  evenly spaced around the outer circumference of the valve body to engage protrusion receiving internal threads (not shown) in the retaining ring  28 . A filter body  44  is shown as being configured with a cylindrical base member  47  which is sized to be snugly fit into the interior of the retaining ring  28 .  
         [0039]    The cylindrical base  47  extends below the filter body a distance that is less than the distance from the top of the retaining ring  28  to the flexible valve. In this manner, the filter body will be sized to be snugly received in the retaining ring which will abut the surface  48  without the cylindrical base touching or otherwise interfering with the function of the one-way valve element (valve disc  26 ). Optionally, a positive expiratory pressure (PEP) valve  50  having a body  51  configured with a base member  52  which is sized to be received in the retaining ring  28  with a snug fit is provided which will enable the mouthpiece to be used as described in U.S. Pat. No. 5,584,285 as either a PEP device or as a part of the breathing circuit described therein with a filter to reduce exposure to excess aerosol medication. This is an important use to reduce health care provider exposure to patient contaminating aerosol or highly toxic medicants.  
         [0040]    The PEP valve  50 , which will be described more fully hereinafter, is provided with the feature of adjustable back pressure which can be used to aid in the deposition and prevent the loss of aerosol in the lungs by creating airflow conditions which are more controlled and thereby permit deeper deposits which are less susceptible to mucocillary removal. Such devices also help improve patient compliance with proper breathing techniques and helps to strengthen the muscles of respiration. This can be accomplished by providing either inhalation resistance, exhalation resistance or both. Further, the incorporation of the variable resistance valve combines maximum aerosol density and respiration of optimum particle size for many treatment options including antibiotics, antivirals, enzymes, bio-reactive substances and genetic therapies.  
         [0041]    The PEP valve  50  has a variable cross-section semicircular slot  53  (FIG. 10) on a rotationally movable plate  54  can be adjusted to present the capability of providing for variable back pressure provided by an adjustably sized outlet for the opening  55  which communicates with the interior of the PEP body  51 . The back pressure may be measured, if clinically desired, by a manometer fitted to the nipple  56  during treatment or exercise. A handle  57  is integral with the plate  54  which is rotatably captive in the PEP body  51  by means of a rivet or pivot  58 . The components are sized to prevent significant leakage which could alter the value of the manometer readings.  
         [0042]    In operation the mouthpiece, the PEP valve may be incorporated into a breathing circuit with or without the one way valve disc and filter  44 , or a pressurized external gas source can be used for various therapies and exercises. Such a device, which can be called a positive airway pressure adjunct and can be used in modified circuits to mobilize secretions, treat atelectasis and provide continuous positive airway pressure (CPAP), positive expiratory pressure (PEP), and expiratory positive airway pressure (EPAP) therapies.  
         [0043]    During CPAP therapy, the patient breathes from a pressurized circuit against a threshold resistor (water-column, weighted, or spring loaded) that maintains consistent preset airway pressures from 5 to 20 cm H 2 O during both inspiration and expiration. By strict definition, CPAP is any level of above-atmospheric pressure. CPAP requires a gas flow to the airway during inspiration that is sufficient to maintain the desired positive airway pressure.  
         [0044]    During PEP therapy, the patient exhales against a fixed-orifice resistor, generating pressures during expiration that usually range from 10 to 20 cm H 2 O. PEP does not require a pressurized external gas source.  
         [0045]    During EPAP therapy the patient exhales against a threshold resistor, generating preset pressures of 10 to 20 cm H 2 O. EPAP does not require a pressurized external gas source.  
         [0046]    The device described herein is suited for PEP therapy in the configurations shown.  
         [0047]    The size of the device provides both convenience comfort and greater independence for the patient during treatment.  
         [0048]    Referring now to FIGS. 11, 12,  13 ,  14 ,  15  and  16 , a filter housing  44  is provided which will fit into the retaining ring  28  as previously described. A filter element  60  is received in the housing  44  which is hinged at the back  61  and closed at the front with a suitable latch structure  62 . The interior of the filter housing  44  is provided with a peripheral apron  63  and locator pins  64  which, in combination with the structure of the rear of the housing locates the filter element  60  on the apron (as shown in FIG. 14). Clamping protrusions  65  molded into the lid  66  of the filter housing  44  are sized to firmly squeeze the edge of the filter element  60  onto the apron  63  to seal and prevent lateral movement of the element during use. Ribs  67  are provided as projections from the cylindrical base  47  to provide central support for the filter element to minimize sagging. The filter element itself is selected to provide a significant reduction in visible particles, a 3M product 0.3 micron Filtrate filter being preferred. In the configuration shown the effective area of the filter exposed to patient exhalation is nominally a surface measuring about 5 cm by about 7.5 cm (i.e. about 37.5 cm 2 ). In order to be most effective, the inlet and exhaust areas of the filter housing should be comparable in cross-sectional area. The textured outlet areas shown in FIG. 11 on the top surfaces of the housing  44  are therefore sized to be substantially the same in effective exhaust area as the inlet cross-sectional area.  
         [0049]    In one arrangement the filter housing may be attached to the retaining ring by way of the PEP valve.  
         [0050]    An alternative construction for the PEP valve will now be described with reference to FIGS. 19 and 20. A cylindrical body  70  has an integral annular flange  71  defining an annular array of three evenly spaced openings  72  defining a passageway through the valve under the control of a rotatable valve member  73  which defines an annular array of openings  74  of the same spacing as openings  72  and having a range of different sizes. The member  73  is rotatable by a handle  75 , integral therewith, relative to the openings  72  to adjust the size of the passageway. The valve member  73  is captively mounted to the body  70  by detents  76  formed on an exterior cylindrical surface of a hollow boss  77  integral with and forming a central opening in the flange  71 . The boss  77  defines a plurality of axially extending slots to provide for assembly as the detents are inserted in a bore of the valve member  73  for engagement with recesses  78  therein. Valve member locating detents  84  resiliently retain the valve member  73  relative to body recesses  85  to retain desired alignment of openings  72  and  74 .  
         [0051]    A poppet valve member  79  is located in the central opening in the flange  71  and seats under the bias of a spring  80  against a valve seat  81 . The poppet valve member  79  includes a guide spider  82  about the spring  80  which is guided by a spider guide opening in the boss  77  to control alignment of the poppet valve member  79  with the valve seat  81 .  
         [0052]    In similar fashion to the PEP valve described with reference to FIGS. 8, 9 and  10 , the body  70  defines a base member  82  to be received in the retaining ring  28  and nipple  83  for attachment to a manometer to measure back pressure, if desired. In use, the passageway is adjusted to desired cross-sectional area by rotation of the valve member  73 . During exhalation, if the back pressure in the body  70  below the poppet valve exceeds the bias of spring  80 , the poppet valve member  79  lifts from the valve seat overcoming the spring bias to relieve the back pressure by allowing exhaled gas to bypass the passageway.  
         [0053]    The PEP valve of this invention has a controllable exhalation resistance of from 5-20 cm. H 2 O (water pressure) at flow rates of 10-55 liters/minute. The pressure relief poppet valve is spring biased to insure that flow resistance values over 20 cm. H 2 O are actively vented.