Abstract:
An inexpensive, disposable, collapsible medication inhalation apparatus for use with an MDI inhaler includes an elongated housing for receiving a plume of medication particles ejected by the MDI inhaler, a mouthpiece, and an inhalation valve disposed between the mouthpiece and the housing. An exhalation port or valve in the mouthpiece allows exhalation through the mouthpiece, presenting very little resistance to the exhalation effort of the patient. An adapter receives and stabilizes a mouthpiece of the MDI inhaler. The inhalation valve includes an inhalation flap hanging adjacent to a valve seat. Exhalation into the mouthpiece presses the inhalation flap against the valve seat, forcing exhaled gas through the exhalation port or valve. Inhalation causes the inhalation flap to swing away from the valve seat to open a path for the medication plume. In one embodiment, the entire inhalation apparatus is constructed from a single sheet of foldable sheet material.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of my commonly assigned patent application entitled “PORTABLE CHAMBER FOR METERED DOSE INHALER DISPENSERS”, filed on Feb. 23, 1998, Ser. No. 028,260, incorporated herein by reference. 
     This application also claims the benefit of prior filed co-pending U.S. provisional application Serial No. 60/099,407 filed Sep. 8, 1998 entitled “COLLAPSIBLE, DISPOSABLE MDI SPACER AND METHOD” by David T. Sladek and Jean W. Keppel. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to a spacer or valved chamber for delivering aerosol medication from an MDI canister in a dispenser (“boot”) supplied by the manufacturer to a patient, through a hand-held chamber operated by the patient, and particularly to an inexpensive collapsible, disposable valved chamber. 
     MDI drug canisters, which have been used since 1956, are sold with a “boot” that includes an actuator, a nozzle, and a mouthpiece. The patient can self-administer the MDI drug using the boot alone; however, the patient must place the mouthpiece of the boot in or near his/her mouth and inhale exactly when the MDI canister is actuated. This is difficult for some patients. Therefore, various suppliers have provided valved chambers that can be used in conjunction with an MDI boot. Such valved chambers may improve drug delivery by reducing the oropharyngeal deposition of the aerosol drug and by making synchronization of the MDI canister actuation with inhalation of the ejected medication less critical. 
     A commonly used valved chamber of this type is manufactured by Monaghan Medical Corporation, marketed under the trademark “AEROCHAMBER”, and refers to U.S. Pat. Nos. 4,470,412 and 5,012,803. Another similar valved chamber of this type is marketed under the trademark “OPTICHAMBER”, described in U.S. Pat. No. 5,385,140 (Smith). 
     The prior AEROCHAMBER device utilizes only an inhalation valve, so the patient must exhale before placing the device in his/her mouth. That presents a significant problem because it is difficult for many patients to initially perform the required sequence of (1) exhaling, (2) then immediately placing the chamber mouthpiece in his/her mouth, (3) then actuating the MDI canister to inject a medication plume into the valved chamber, and (4) then taking a slow deep breath and holding his/her breath for a few seconds. The prior OPTICHAMBER device provides both an inhalation valve and an exhalation valve, so that device need not be removed from the patient&#39;s mouth in order to use it. 
     A problem of the prior art is that the prior valved chamber devices are far too expensive to be considered disposable, and/or they are not at all collapsible or are insufficiently collapsible to be carried conveniently in a briefcase, vest pocket, or the like. U.S. Pat. Nos. 4,637,528 and 4,641,644 disclose aerosol inhalation devices that are partly collapsible, but not to a generally thin, flat configuration. U.S. Pat. No. 4,953,545 discloses a chamber that is disposable but not collapsible. 
     The retail cost of prior valved chambers described above typically is as much as nearly $20.00. This cost may be acceptable to patients having chronic conditions that require frequent use of MDI inhaler medication for a long period of time, provided the patients are willing to frequently clean such MDI inhalers. However, many patients need MDI inhaler medications for only a short period of time, in which case the high cost of the prior art valved chambers is very unsatisfactory, especially if a substantially lower cost alternative were available. 
     Thus, there is an unmet need for an improved valved chamber device which avoids the above mentioned problems of the prior art and provides a portable, light, reliable, inexpensive, disposable, collapsible, easy-to-use valved chamber for use with MDI inhalers. There also is an unmet need for an improved valved chamber device which is sufficiently inexpensive that it can be used as a disposable diagnostic dosing aid, temporary medication delivery aid, or teaching aid for instructing patients in the use of valved chamber devices. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the invention to provide an inexpensive, disposable, collapsible valved chamber for delivering MDI medications or vaccines. 
     It is another object of the invention to provide an inexpensive, disposable valved chamber which is collapsible to a flat configuration. 
     It is another object of the invention to provide an easily manufacturable valved chamber which is collapsible to a flat configuration. 
     It is another object of the invention to provide a valved chamber which is sufficiently inexpensive that it can be used as a discardable diagnostic dosing aid, temporary medication delivery aid, or training aid by means of which a health care provider can demonstrate proper techniques for using a permanent valved chamber. 
     Briefly described, and in accordance with one embodiment thereof, the invention provides an elongated housing for receiving a plume of medication particles ejected by an MDI inhaler, having a medication inlet end and a medication outlet end, a mouthpiece at the medication outlet end, a one-way inhalation valve disposed between the mouthpiece and a first volume bounded by the housing for allowing flow of gas from the first volume to the mouthpiece, an exhalation port or valve disposed in the mouthpiece for allowing flow of gas from within the mouthpiece to ambient atmosphere outside of the apparatus, an adapter connected to the medication inlet end for receiving and stabilizing a mouthpiece of the MDI inhaler, wherein the one-way inhalation valve includes an inhalation membrane adjacent to a valve seat. An exhalation by a patient into the mouthpiece presses the inhalation membrane against the valve seat to prevent flow of exhaled gas from the mouthpiece into the first volume, causing the exhaled gas to flow from the mouthpiece through the exhalation port or valve. An inhalation from the mouthpiece by the patient causes the inhalation membrane to swing away from the valve seat and allow passage of air from the volume into the mouthpiece. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of the outer surface of a sheet from which a first embodiment of the collapsible, disposable valved chamber of the present invention is constructed. 
     FIG. 2 is a longitudinal section view of the collapsible, disposable valved chamber of FIG. 1 after tabs  50  and  50 A have been adhesively attached and the mouthpiece section  53  has been partially folded and adhesively attached and the unit has been folded for shipping. 
     FIG. 3 is a longitudinal section view of the collapsible, disposable valved chamber of FIGS. 1 and 2 erected and ready for use. 
     FIG. 4 is a transverse section view of the collapsible, disposable valved chamber compressed for shipping. 
     FIG. 5 is an elevational view of the m mouth piece end of the erected structure as shown in FIG.  3 . 
     FIG. 6 is an inlet end elevational view of the erected inhaler as shown in FIG.  3 . 
     FIG. 7 is a plan view of the outer surface of a sheet from which a second embodiment of the collapsible, disposable valved chamber of the present invention is constructed. 
     FIG. 8 is a plan view of the inner surface of the sheet of FIG. 1, with the mouthpiece pull-out section  53  of FIG. 7 partially folded back and adhesively attached, the rest being positioned in a collapsed configuration. 
     FIG. 9 is a perspective view illustrating “assembly” of the boot adapter end of the valved chamber. 
     FIG. 10 is a perspective view illustrating “assembly” of the mouthpiece section of the valved chamber. 
     FIG. 11 is a partial perspective view of the valved chamber of FIG. 7 in its expanded configuration, with the boot of an MDI inhaler inserted. 
     FIG. 12 is an upper front left perspective view of a third embodiment of a collapsible, disposable valved chamber of the present invention, shown in assembled form. 
     FIG. 13 is a perspective partial see-through view of the embodiment of FIG. 12 with dotted lines illustrating the inhalation port structure. 
     FIG. 14 is a perspective view of the bottom, side, and inlet ends of the valved chamber of FIGS. 12 and 13. 
     FIG. 15 is a perspective view showing the bottom, side, and mouthpiece ends of the valved chamber of FIGS. 12-14. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows the outer surface of a sheet  1 A from which a preferred first embodiment of the valved chamber of the present invention is assembled. FIG. 2 shows a longitudinal section view of the assembled chamber, folded or collapsed for shipping. FIG. 4 shows a corresponding transverse section view of the collapsed valved chamber. FIG. 3 shows a longitudinal section view of the chamber assembled, expanded, and ready for use. 
     Referring to FIGS. 1-4, the entire valved chamber structure, except for the subsequently described inhale valve membrane  76 , exhale valve membrane  75 , and viewing window membrane  8 A, is punched from a single sheet of suitable material, such as paperboard, plastic, spun nonwoven polymer such as TYVEK by DuPont, or the like. Note that reference character  1 A is used herein to designate both sheet  1 A and the valved chamber assembled therefrom. 
     It also should be noted that the terms top, bottom, left, right, front, and back or rear are used from the viewpoint of a user of the assembled valved chamber facing the mouthpiece openings  72 , with viewing window  8  oriented upward as shown in FIG.  3 . 
     Sheet  1 A includes a bottom section  2  connected along a fold line  19  to a right side section  18 . Right side section  18  is connected along a fold line  20  to a top section  30 . Top section  30  is connected along a fold line  31  to an adhesive tab section  47 . An adhesive  50  is provided on section  47 . 
     Bottom section  2  includes an inner boot adapter panel  2 A having therein a boot receiving hole  4 . Inner boot adapter panel  2 A is connected along an arcuate fold line  3 A to a bottom panel  2 B of bottom section  2 . A left side section  50 A is attached along a straight fold line  74  to the left edge of bottom section  2 . 
     An exhale valve includes two exhale valve holes  73  in bottom panel  2 B and a flexible exhale valve membrane, which typically is transparent plastic film, adhesively attached along an edge to the outer surface of bottom panel  2 B to cover exhale holes  73 . 
     The front end of bottom panel  2 B is connected along straight fold line  41  to an inner mouthpiece section  53 . (It should be noted that all of the fold lines illustrated in FIG. 1 are “score lines” punched into the material of which sheet  1 A is formed at the same time sheet  1 A is punched out of stock material.) Inner mouthpiece section  53  includes a panel  54  with one edge connected along fold line  41  to bottom panel  2 B and another opposite edge connected along fold line  54 A to a panel  52 . Panel  54  has an inner mouthpiece hole  38  punched therein. Inner mouthpiece hole  38  is aligned with two mouthpiece holes  72  in subsequently described panel  15  of outer mouthpiece section  53 A when the valved chamber  1 A is in its expanded configuration and ready for use. Inner mouthpiece section  53  also includes a panel  56  having an edge connected to panel  52  along fold line  56 A. Panel  56  includes an elongated inhale valve hole  12 , and is connected along straight fold line  49 A to an adhesive attachment panel  49 , which has a truncated recess  49 B in its outer edge. A flexible inhale valve membrane  76  is adhesively attached along one edge to the inner surface of panel  52  and/or  56 . (The term “adhesive” as used herein is intended to include various attachment materials, including true adhesive materials and also materials such as velcro that provide attachment between two surfaces in response to pressing them together.) 
     Right side panel  18  of sheet  1 A is connected between bottom panel  2 B and a top panel  30 B of top section  30  by two straight horizontal fold lines  19  and  20 . 
     Top section  30  includes an outer boot adapter panel  32  having an arcuate outer edge as illustrated, and is connected to the rear edge of top panel  30 B along an arcuate fold line  30 A. Outer boot adapter panel  32  includes an elongated opening  4 A having semi-circular “scalloped” sections  4 B on opposite edges thereof. The scalloped sections  4 B are formed by a plurality of spaced slits such as  4 C, so that in its assembled, expanded configuration opening  4 A of inner boot adapter panel  32  is aligned with circular opening  4  in inner boot adapter panel  2 A and the scalloped sections  4 B yield to snugly accommodate the outlet end of various conventional MDI canister boots. 
     The front edge of bottom panel  30 B is connected along straight fold line  13  to an outer mouthpiece section  53 B. Outer mouthpiece section  53 B includes a panel  15  having two openings  72  therein which are aligned with inner mouthpiece opening  38  and with inhale valve opening  12  when the chamber  1 A is assembled and expanded. Panel  15  also is connected along fold line  16 A to panel  16 . Panel  16  has an elongated opening  68  which is aligned with exhale valve openings  73  in bottom panel  2 B in the assembled chamber  1 A. A pull tab  71  is attached along line  71 A to the outer edge of panel  16 . A semi-rectangular cut  69  in panel  16  forms a lock tab  69 A which is integral with pull tab  71  and fits into lock tab slot  67  in bottom panel  2 B. 
     When sheet  1 A is assembled as subsequently explained, inner mouthpiece section  53 , the portion of bottom panel  2 B indicated by reference numeral  53 A, and outer mouthpiece section  53 B are included in the “mouthpiece section” of medication inhalation apparatus  1 A. 
     Top panel  30 B has an elongated window  8  therein for viewing the interior of valved chamber  1 A when it is in its assembled configuration. Dotted line  8 A designates a transparent membrane or sheet adhesively attached to the underside of panel  2 B as illustrated in FIGS. 1 and 2. Preferably, window material  8 A is composed of plastic film. 
     Outer boot adapter panel  32  of top section  30  includes a lock section  5  connected along arcuate fold line  30 B to the outer edge of outer boot panel  32 . Lock section  5  includes a pull tab  5 A with a semi-rectangular cut  6  that forms a lock tab  6 A which fits into lock tab slot  33  in bottom panel  2 B. Lock tab slot  33  in bottom panel  2 B is positioned relative to scored arcuate fold line  3 A to receive locking tab  6 A of outer boot adapter panel  32 . 
     To assemble sheet  1 A into chamber  1 A, exhale membrane  75 , inhale membrane  76 , and window membrane  8 A are properly adhesively attached to the inner surface of sheet  1 A. Inner mouthpiece section  53  is folded over the inner surface of bottom panel  2 B, and the inner surface of panel  49  is adhesively attached by adhesive  27  to the inner surface as shown in FIG.  2 . Then, section  47  is attached by adhesive  50  to left edge  50 A after bottom section  2  has been folded under top section  30 . When top panel  30 B is pressed down against bottom panel  2 B, a longitudinal section view of the assembled, collapsed chamber  1 A appears as shown in FIG.  2 . In FIG. 1, dotted lines  49 ′ show the location of panel  49  when its inner surface is adhesively or otherwise attached to the inner surface of bottom panel  2 B, and numeral  49 A′ indicates the corresponding location of fold line  49 A. The assembled, collapsed chamber  1 A then can be expanded by the user to have the longitudinal cross section shown in FIG. 3 by manipulating the collapsed structure so that sides  18  and  50 A are perpendicular to top panel  30 B and bottom panel  2 B, folding panel  54  up so it and panel  56  are approximately perpendicular to top panel  30 B and bottom panel  2 B, pulling on pull tab  71  of outer mouthpiece section  53 B after drawing panel  16  under bottom panel  2 B, to insert lock tab  69  into lock tab slot  67 , as shown in FIG.  3 . Inner boot adapter panel  2 A is bent along arcuate fold line  3 A upward so it is approximately perpendicular to top panel  30 B and bottom panel  2 B. Then outer boot adapter panel  32  is bent down along fold line  30 A so it is against inner boot adapter panel  2 A and hole  4 A is aligned with hole  4 . Pull tab  5 A is deployed to insert lock tab  6 A into lock tab slot  33 . The mouthpiece end of assembled and expanded chamber  1 A then appears as shown in FIG. 5, and the boot-adapter-receiving end appears as shown in FIG.  6 . Chamber  1 A is ready to receive the “mouthpiece” end of boot adapter  77 . 
     As shown in FIG. 3, the “mouthpiece” end of the boot adapter  77  of a conventional inhaler containing an MDI canister  78  is inserted through inlet hole  4 A of outer boot adapter panel  32  and hole  4  of inner boot adapter panel  2 A of assembled and expanded chamber  1 A. As the user inhales through aligned mouthpiece openings  38  and  72  of panels  54  and  15 , respectively, exhale membrane  75  seals exhale hole  73  and inhale membrane  76  swings to the right in the direction indicated by arrow  89  and a substantial portion of the expanding plume (not shown) of medication particles from MDI canister  78  and a nozzle in boot adapter  77  in the main interior volume  90  of chamber  1 A is drawn into the user&#39;s mouth. When the user exhales, membrane  76  swings back to its original position to seal inhale opening  12 . The exhaled air forces part of exhale membrane  75  to open in the direction of arrow  91 , so no exhaled air is forced into volume  90  to be rebreathed. 
     Referring to FIG. 7, a second embodiment of the valved chamber of the invention is disclosed. The same or similar reference characters are used whenever practical to designate similar parts. FIG. 7 shows the outer surface of the sheet  1 B from which valved chamber of the present invention is erected or assembled. The entire structure illustrated is punched from a single sheet of suitable material, such as paperboard, plastic, spun nonwoven polymer such as TYVEK or the like. Sheet  1 B includes a top section  2  connected along a fold line  19  to a left side section  18 . Left side section  18  is connected along a fold line  20  to a bottom section  30 . Bottom section  30  is connected along a fold line  31  to a right side section  47 . An adhesive tab  50  is connected along a fold line  48  to right side section  47 . 
     Top section  2  includes an outer boot adapter panel  2 A having therein a boot receiving hole  4 . Outer boot adapter panel  2 A is connected along an arcuate fold line  3 A to a top panel  2 B and also to a tab  5  along an arcuate fold line  3 B. A lock tab  6  formed by an arcuate slit  6 A in tab  5  is disposed in tab  5 . 
     Top panel  2 B has an elongated window  8  therein for viewing the interior of valved chamber  1 B when it is in its “assembled” or expanded or “erected” configuration. (Numeral  1 B is used herein to designate both sheet  1 B and the valved chamber erected or assembled therefrom.) Dotted line  8 A designates a transparent sheet adhesively attached to the underside of panel  2 B as illustrated in FIG.  7 . Preferably, window material  8 A is composed of plastic film. The right end of panel  2 B is connected along arcuate fold line  11  to an outer mouthpiece section  2 C. All of the fold lines illustrated by dashed lines in FIG. 7 are “score lines” punched into the material of which sheet  1 B is formed at the same time sheet  1 B is punched out of stock material. Outer mouthpiece section  2 C includes a mouthpiece top panel  10 . Mouthpiece top panel  10  is connected along a fold line  13  to a mouthpiece end panel  15 , which has therein an outer mouthpiece opening  12 , as shown. Mouthpiece end panel  15  is connected along a fold line  14  to a locking panel including two spaced apart tabs  16 . Each tab  16  includes a lock tab  17  formed by a slit  17 A and tab  16 . 
     Left side section  18  includes a tab  18 A connected by a vertical fold line  23  to a left side panel  18 B. The other end of left side panel  18 B includes a vertical fold line  21  and two inclined, perforated fold lines  22  to form a trapezoid, as shown. Their function will be described hereinafter, to establish the taper or slope of upper mouthpiece top panel  10  when the valved chamber  1 B is fully expanded. 
     Bottom section  30  includes an inner boot adapter panel  32  having an arcuate left edge as illustrated, and is connected to bottom panel  30 B along an arcuate scored fold line  30 A, as shown. Inner boot adapter panel  32  includes an elongated opening  4 A having semi-circular “scalloped” portions  4 B on opposite edges thereof. The scalloped sections  4 B are formed by a plurality of spaced slits such as  4 C, so that in its constructed, expanded configuration opening  4 A of inner boot adapter panel  32  is aligned with circular opening  4  in outer boot adapter panel  2 A and the scalloped portions  4 B yield, to snugly accommodate the outlet end of a conventional MDI canister boot. 
     Bottom section  30  includes bottom panel  30 B having an edge connected along fold line  30 A to inner boot adapter panel  32 , as shown. The other edge of bottom panel  30 B is connected along scored fold line  36  to mouthpiece bottom panel  35 , which is also connected along scored fold line  41  to the edge of inner mouthpiece section  53 , as shown. Mouthpiece bottom panel  35  has two vertical slots  40  adjacent to fold line  36  as shown to receive locking tabs  17  of outer mouthpiece section  2 C when valved chamber  1 B is constructed in its expanded configuration. An exhale valve tab  38  is formed by a U-shaped slit  38 A in mouthpiece bottom panel  35 , as shown. An optional vertical slot  67  is for receiving subsequently described optional lock tab  66  in pull tab  62 . 
     Slot  33  in bottom panel  30 B is centered relative to scored arcuate fold line  30 A and receives locking tab  6  of top section  2 . 
     Inner mouthpiece section  53  includes a fold-back panel  54  which has the same rectangular size and shape as mouthpiece bottom panel  35 . An exhale hole  38 A is approximately centered in fold-back panel  54  as shown, so that exhale hole  38 A is aligned with exhale valve tab  38  when panel  54  is folded back against and adhesively attached to mouthpiece bottom panel  35 . When valved chamber  1 B is constructed in its expanded configuration, locking tabs  17  slide into slots  40  and thus slip in between panel  54  and panel  35 . 
     Inner mouthpiece section  53  is connected at its midsection along a scored fold line  56 A to an inhale valve panel  56  having an inhale valve opening  12 B centered therein, as shown. An edge of inhale valve panel  56  is connected along a vertical fold line  56 B to a generally trapezoidal panel  59 , as shown. An inhale valve flap  60  is hingeably connected to valve panel  56  along fold line  56 B by a plurality of short, spaced hinge points  61 . The rest of valve flap  60  is surrounded by a slit  60 A punched through trapezoidal panel  59  so flap  60  is quite freely hinged to inhale valve panel  56 . Alternatively, inhale valve panel  56  can be thin, flexible plastic adhesively, hingeably attached along one side to panel  56  to cover an inhale hole in panel  56  during exhaling and swing away to uncover such inhale hole during inhaling. 
     Trapezoidal panel  59  contains a mouthpiece end panel  70  having a mouthpiece opening  12 A generally centered therein as illustrated. Trapezoidal panel  59  is connected by a scored fold line  64  to a pull tab  62  having an optional U-shaped locking tab  66  formed therein by a U-shaped slit  66 A. 
     Right side section  47  includes a fold tab  47 B having one edge connected along a scored fold line  25  to an elongated right side panel  47 A. Right side panel  47 A is connected at another edge to a portion including a vertical, scored fold line  26  and two inclined perforated fold lines  44  forming a trapezoid, similarly to the above described trapezoid formed by fold lines  21  and  22  in left side section  18 . 
     Referring to FIG. 8, which shows the inner surface of sheet  1 B, the first step in the “assembly” or “construction” of the valved chamber  1 B according to the present invention is to fold the inner surface of fold-back panel  54  along scored fold line  41 , press it against the inner surface of mouthpiece bottom panel  35 , and adhesively attach those two surfaces together. The remaining portions of mouthpiece section  53 , including inhale valve panel  56 , trapezoidal panel  59 , and pull tab  62 , are folded back along fold line  56 A, as shown in FIG.  2 . In this configuration, exhale valve opening  38 A is generally aligned with exhale valve flap  38 . 
     The next step is to fold top section  2  and left side section  18  along fold line  20 , over and parallel to bottom section  30  and right side section  47 , so that the cut edge of top section  2  as shown in FIG. 8 is aligned with scored fold line  48 . Then adhesive tab  50  is folded over the outer surface of the cut edge of top section  2  along scored fold line  48  and adhesively attached thereto. This provides the collapsed structure, ready to be shipped. 
     Referring next to FIG. 9, the next step in the construction is to fold tabs  18 A and  47 B (FIG. 7) inward and then fold inner boot adapter panel  32  upward along scored arcuate fold line  30 A as shown. Then, outer boot adapter panel  2 A is folded downward along scored arcuate fold line  3 A, as shown, and locking tab  6  of tab  5  is inserted into slot  33 . 
     Referring to FIG. 10, pull tab  62  is pulled outward, causing inhale valve panel  56  to be erected into a vertical position, with tabs  55 , which are folded along fold lines  65 , acting as stops. Trapezoidal panel  59  and pull tab  62  appear as shown. The next to last step in the expansion of valved chamber  1 B is to fold pull tab  62  along fold line  64  as shown and insert optional locking tab  66  of pull tab  62  into slot  67 . 
     The final step in the construction is to pull outer mouthpiece end panel  15  and tabs  16  over and around the end of mouthpiece pull-out section  53 , and insert locking tabs  17  into slots  40 . 
     Next, the mouthpiece end of an MDI boot  77  as shown in FIG. 11 is inserted into the aligned openings  4  and  4 A of boot adapter panels  2 A and  32 , respectively. The valved chamber  1 B then is ready for use by the patient by simultaneously inhaling while actuating the MDI canister  78  in MDI boot  77 . MDI canister  78  ejects a medication plume into the interior volume of valved chamber lB, which is visible to the patient through window  8 . The relative vacuum created by the patient&#39;s inhaling causes inhale flap  60  to pivot or swing away from opening  12 B in inhale valve panel  56 , so a substantial portion of the ejected plume passes through inhale valve opening  12 B and mouthpiece end opening  12 A into the mouth of the patient. 
     When the patient exhales before repeating the above procedure, inhale flap  60  is forced, by the increased pressure caused by the exhaling, against the peripheral portion of inhale panel  56  around opening  12 B, so that the exhaled air flows through the opening  38 A in fold-back panel  54 . As the exhaled air flows through exhale opening  38 A, it pushes exhale flap  38  outward so that the exhaled air escapes to the outside atmosphere. Similarly to inhale flap  60  described above, exhale flap  38  could alternatively be formed of thin, flexible plastic adhesively, hingeably attached to cover and seal an exhale hole during inhaling by the patient and pivot away from the exhale hole during exhaling by the patient. 
     Referring to FIGS. 12-15, a third embodiment of the collapsible, disposable valved chamber is designated by numeral  1 C. Where appropriate, the same or similar reference numerals are used as in the embodiment of FIGS. 1-6 to designate the same or corresponding parts. In FIG. 12, chamber  1 C includes two main parts  80  and  81 , which are separately punched out of a sheet of suitable paper or plastic material, and then are adhesively attached together to provide a disposable collapsible spacer which may be packaged and shipped in a flat configuration and then assembled into an expanded configuration for use by the patient. Numeral  80  in FIGS. 12-15 designates one of the two sections referred to as the “mouthpiece section”. Numeral  81  designates a second section referred to as the “chamber section”, which includes a collapsible end section  100  that automatically folds when chamber section  81  and mouthpiece section  80  are collapsed as a unit. Mouthpiece section  80  has four attachment flaps  94 A- 94 D which are adhesively attached to the outer edge portions of panels  30 B,  18 ,  2 B, and  50 A, respectively, of chamber section  81 . 
     Referring to the partial “see through” view of FIG. 13, collapsible end section  100  is referred to as “autobottom”  100 , and includes an upper flap  82  having a first section  82 A connected along a straight horizontal first fold line  82 B to top panel  30 B of chamber section  81  and a second section  82 C connected along a straight vertical fold line  82 D to right side panel  18 . To allow collapsing of autobottom  100 , second section  82 C of upper flap  82  is connected to first section  82 A along an oblique fold line  82 E. First section  82 A of upper flap  8  has an inhalation hole  12  therein, with the upper edge of an inhale membrane  76  adhesively attached to the front face of first section  82 A of upper flap  82 , as shown in FIG.  13 . The lower portion of inhale membrane  76  covers and seals inhalation hole  12  during exhalation by the patient and swings toward mouthpiece inhalation hole  72  when the user inhales. When chamber section  81  is collapsed, first section  82 A and second section  82 C of upper flap  82  fold inwardly into chamber section  81  along fold lines  82 B,  82 D, and  82 E. 
     Autobottom section  100  also includes a similar lower flap  84  having a first section  84 A connected along a straight horizontal first fold line  84 B to bottom panel  2 B of chamber section  81  and a second section  84 C connected along a straight vertical fold line  84 D to right side panel  50 A indicated in FIG.  15 . Referring to FIG. 13, to allow collapsing of autobottom  100 , second section  84 C is connected to first section  84 A along an oblique fold line  84 E. When chamber section  81  and mouthpiece section  80  are assembled, lower flap  84  is in front of upper flap  82 . The inner surface of lower panel  84  abuts the outer surface of upper flap  82  so as to form a seal with the portion of upper flap  82  below inhale valve membrane  76 , leaving inhale valve membrane  76  free to swing toward inhalation openings  72  when the user inhales. When chamber section  81  is collapsed, first section  84 A and second section  84 C of lower flap  84  fold inwardly behind inwardly folding upper flap  82  into chamber section  81  along fold lines  84 B,  84 D, and  84 E. 
     Referring to FIGS. 12-15, mouthpiece section  80  includes an inclined top panel  104  and an end panel  15  in which above mentioned inhalation holes  72  are formed as shown in FIG.  12 . Mouthpiece section  80  also includes an inclined bottom panel  85  as shown in FIG.  15 . Inclined fold lines such as  83  allow the side panels of mouthpiece section  80  to fold slightly inward so that top panel  104  and bottom panel  85  taper to the height of mouthpiece end panel  15  as shown. An exhalation valve hole  73  is provided in top panel  104 , and the lower edge of an exhale membrane  75  is adhesively attached to the outer surface of top panel  104  to seal exhalation valve opening  73  when the user inhales, and to swing away from exhalation valve opening  73  when the user exhales. Numeral  73 ′ in FIG. 12 indicates an alternative location for exhalation valve hole  73 . 
     The invention thus provides an improved valved chamber in which the inhalation flap opens the inhale air path as the patient inhales. The exhalation valve hole  73  and exhalation valve membrane  75  present very low resistance to exhaled air flow, so the patient is not so likely to feel a need to remove the chamber from his/her mouth during the exhalation that precedes actuation and inhalation. Therefore, with suitable instruction, most patients can easily synchronize inhalation with actuation of the MDI canister, because of the smaller number of steps that the patient must coordinate during the critical few seconds while the medication is being delivered. 
     Thus, the invention provides a disposable valved chamber which also allows for natural inhalation and exhalation by the patient. The described valved chamber device can be maintained in a collapsed, flat configuration, suitable for storage in a suit coat pocket or a briefcase, and expanded immediately prior to use, after which it can be discarded or re-folded for later use by the same patient. The described valved chamber is ideal for use as a training aid to allow a health care worker to demonstrate its use to patients needing to receive an aerosol medication from an MDI inhaler. The invention also is well suited for use in hospital emergency rooms, health-care clinics, pulmonary function labs, or infirmaries. In addition, its portability and low cost make it ideal for use by relief or world health organizations, especially when aerosol vaccines become available. 
     While the invention has been described with reference to several particular embodiments thereof, those skilled in the art will be able to make the various modifications to the described embodiments of the invention without departing from the true spirit and scope of the invention. It is intended that all elements or steps which are insubstantially different or perform substantially the same function in substantially the same way to achieve the same result as what is claimed are within the scope of the invention. For example, an exhalation port could be provided in the wall of the mouthpiece section instead of using the disclosed one-way exhalation valve  73 , 75 . Various other ways of folding the sheet material to achieve the collapsed/expanded configurations can be provided. Different arrangements of lock tabs and lock tab receiving slots than disclosed herein could be provided, or velcro or similar attachment materials could be used instead of the lock tabs and lock tab receiving slots.