Patent Publication Number: US-8534284-B2

Title: Respiratory therapy device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 11/670,867, entitled “Passive Respiratory Therapy Device” filed on Feb. 2, 2007, which is a continuation of U.S. patent application Ser. No. 11/559,288, entitled “Respiratory Therapy Device and Method” filed on Nov. 13, 2006; the teachings of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present disclosure relates to respiratory therapy devices and methods for administering breathing-relating treatments (e.g., oscillatory, continuous, etc.) to a patient. More particularly, it relates to respiratory therapy devices capable of creating oscillatory respiratory pressure pulses in response to the patient&#39;s expiratory airflow alone, or when connected to a source of positive pressure fluid (e.g., air, oxygen, etc.), or both. One or more additional therapies (e.g., continuous positive airway pressure, continuous positive expiratory pressure, delivery of aerosolized medication, etc.) are optionally available in some embodiments. 
     A wide variety of respiratory therapy devices are currently available for assisting, treating, or improving a patient&#39;s respiratory health. For example, positive airway pressure (PAP) has long been recognized to be an effective tool in promoting bronchial hygiene by facilitating improved oxygenation, increased lung volumes, and reduced venous return in patients with congestive heart failure. More recently, positive airway pressure has been recognized as useful in promoting mobilization and clearance of secretions (e.g., mucous) from a patient&#39;s lungs. In this regard, expiratory positive airway pressure (EPAP) in the form of high frequency oscillation (HFO) of the patient&#39;s air column is a recognized technique that facilitates secretion removal. In general terms, HFO reduces the viscosity of sputum in vitro, which in turn has a positive effect on clearance induced by an in vitro simulated cough. In this regard, HFO can be delivered or created via a force applied to the patient&#39;s chest wall (i.e., chest physical therapy (CPT), such as an electrically driven pad that vibrates against the patient&#39;s chest), or by applying forces directly to the patient&#39;s airway (i.e., breathing treatment, such as high frequency airway oscillation). Many patients and caregivers prefer the breathing treatment approach as it is less obtrusive and can more easily be administered. To this end, PAP bronchial hygiene techniques have emerged as an effective alternative to CPT for expanding the lungs and mobilizing secretions. 
     In the context of high frequency oscillatory breathing treatments, various devices are available. In general terms, respiratory therapy devices typically include one or more tubular bodies through which a patient breaths, with the tubular body or bodies creating or defining a patient breathing circuit. With this in mind, the oscillatory airflow effect can be created by periodically generating a pressure or positive airflow in the patient breathing circuit during one or both of an inspiratory phase or expiratory phase of the patient&#39;s breathing cycle. For example, a positive expiratory pressure (PEP) can work “against” the patient&#39;s breath during the expiratory phase of breathing. The pressure can be generated by creating a periodic (or in some instances continuous) resistance or restriction in the patient breathing circuit to expiratory airflow from the patient, or by introducing a forced fluid flow (from a positive pressure gas source) into the patient&#39;s breathing circuit in a direction opposite of the patient&#39;s exhaled air. With the airflow resistance approach, a separate, positive pressure gas source is not required. More particularly, many oscillatory positive expiratory pressure (“oscillatory PEP”) therapy devices utilize the patient&#39;s breath alone to drive an oscillatory fluid flow restriction, and thus can be referred to as “passive” devices (in contrast to an “active” respiratory therapy device that relies on a separate source of positive pressure gas as described below). Passive oscillatory PEP devices are self-administering and portable. 
     The Flutter® mucus clearance device (available from Axcan Scandipharm Inc., of Birmingham, Ala.), is one example of an available passive, oscillatory PEP therapy device. In general terms, the Flutter device is pipe-shaped, with a steel ball in a “bowl” portion of a housing that is loosely covered by a perforated cap. The ball is situated within an airway path defined by the device&#39;s housing; when the patient exhales into the housing, then, the ball temporarily obstructs airflow, thus creating an expiratory positive airway pressure. The bowl within which the ball is located allows the ball to repeatedly move (e.g., roll and/or bounce) or flutter to create an oscillatory or vibrational resistance to the exhaled airflow. While relatively inexpensive and viable, the Flutter device is fairly sensitive, requiring the patient to maintain the device at a particular angle to achieve a consistent PEP effect. Other passive oscillatory positive expiratory pressure devices, such as the Acapella® vibratory PEP therapy system (available from Smiths Medical of London, England) and the Quake® secretion clearance therapy device (available from Thayer Medical Corp., of Tucson, Ariz.) are known alternatives to the Flutter device, and purport to be less sensitive to the position in which the patient holds the device during use. While these and other portable oscillatory PEP therapy devices are viable, opportunities for improvement remain, and patients continue to desire more uniform oscillatory PEP results. 
     As an alternative to the passive oscillatory PEP devices described above, continuous high frequency oscillatory (CHFO) treatment systems are also available. In general terms, the CHFO system includes a hand-held device establishing a patient breathing circuit to which a source of positive pressure gas (e.g., air, oxygen, etc.), is fluidly connected. The pressure source and/or the device further include appropriate mechanisms (e.g., control valves provided as part of a driver unit apart from the hand-held device) that effectuate intermittent flow of gas into the patient breathing circuit, and thus percussive ventilation of the patient&#39;s lungs. With this approach, the patient breathes through a mouthpiece that delivers high-flow, “mini-bursts” of gas. During these percussive bursts, a continuous airway pressure above ambient is maintained while the pulsatile percussive airflow periodically increases airway pressure. Each percussive cycle can be programmed by the patient or caregiver with certain systems, and can be used throughout both inspiratory and expiratory phases of the breathing cycle. 
     Examples of CHFO devices include the IPV® ventilator device (from PercussionAire Corp., of Sandpoint, Id.) and a PercussiveNeb™ system (from Vortran Medical Technology 1, Inc., of Sacramento, Calif.). These and other similar “active” systems are readily capable of providing not only CHFO treatments, but also other positive airflow modes of operation (e.g., continuous positive airway pressure (CPAP)). However, a positive pressure source is required, such that available active respiratory therapy systems are not readily portable, and are relatively expensive (especially as compared to the passive oscillatory PEP devices described above). Oftentimes, then, active respiratory treatment systems are only available at the caregiver&#39;s facility, and the patient is unable to continue the respiratory therapy at home. Instead, a separate device, such as a portable, passive oscillatory PEP device as described above must also be provided. Further, the hand-held portion of some conventional active respiratory therapy systems must be connected to an appropriate driver unit that in turn is programmed to effectuate the desired fluid flow to the patient (e.g., CHFO, CPAP, etc.). That is to say, the hand-held portion of some active systems is not self-operating, but instead relies on the driver unit for applications. Any efforts to address these and other limitations of available active respiratory therapy devices would be well-received. This limitation represents a significant drawback. 
     In light of the above, a need exists for respiratory devices capable of providing oscillatory PEP therapy utilizing the patient&#39;s breath alone, as well as CHFO therapy (and optionally other therapies such as CPAP) when connected to a positive pressure source. In addition, improved passive oscillatory PEP or active respiratory therapy devices are also needed. 
     SUMMARY OF THE INVENTION 
     Some aspects in accordance with principles of the present disclosure relate to a device for providing respiratory therapy to a patient during at least a portion of a patient breathing cycle otherwise including an inspiratory phase and an expiratory phase. The device includes a housing and an interrupter valve assembly. The housing includes a patient inlet, an exhaust outlet, a chamber, and a pressurized fluid supply inlet. The chamber is fluidly disposed between the patient inlet and the exhaust outlet. The interrupter valve assembly is associated with the housing and includes a control port fluidly connecting the patient inlet and the chamber. Further, the interrupter valve assembly includes a valve body adapted to selectively obstruct fluid flow through the control port. With this in mind, the device is adapted to operate in a first, passive mode and a second, active mode. In the passive mode, positive airflow to the supply inlet does not occur. The interrupter valve assembly interacts with exhaled air from the patient to create an oscillatory positive expiratory pressure effect during at least the expiratory phase. Conversely, in the active mode, positive fluid flow to the fluid supply inlet occurs and the interrupter valve assembly interacts with this fluid flow to create a continuous high frequency oscillation effect. With this configuration, then, the respiratory device can serve as a passive, oscillatory PEP device for use by a patient at virtually any location. In addition, when connected to a positive pressure gas source, the respiratory therapy device provides active therapy. In some embodiments, the interrupter valve assembly includes a drive mechanism akin to a reverse roots blower, utilizing forced air (e.g., either the patient&#39;s exhaled airflow or airflow from a separate positive gas source) to cause rotation of the roots blower lobes, that in turn cause the valve body to periodically open and close the control port. In other embodiments, the device can provide or facilitate one or more additional therapies such as continuous PEP, CPAP, delivery of aerosolized medication, etc. 
     Other aspects in accordance with the present disclosure relate to a method of providing respiratory therapy to a patient during at least a portion of a patient breathing cycle including an inspiratory phase and an expiratory phase. The method includes providing a respiratory therapy device including a housing and an interrupter valve assembly. The housing includes a patient inlet, an exhaust outlet, and a pressurized fluid supply inlet. The interrupter valve assembly is adapted to selectively interrupt fluid flow to or from the patient inlet. A source of pressurized fluid is fluidly coupled to the fluid supply inlet. Continuous high frequency oscillation treatment is administered to the patient via the therapy device, with the therapy device operating in an active mode. Fluid flow from the source of pressurized fluid to the fluid supply inlet is discontinued. The patient is then prompted to repeatedly perform a patient breathing cycle using the therapy device. In this regard, the therapy device administers an oscillatory positive expiratory pressure treatment to the patient while operating in a passive mode. In some embodiments, the passive mode of operation is characterized by the level of oscillatory positive expiratory pressure treatment being a function of a breathing effort of the patient, whereas the active mode of operation is characterized by a level of continuous high frequency oscillation treatment being independent of the patient&#39;s breathing effort. In yet other embodiments, the method further includes administering one or more additional therapies to the patient via the device, such as CPAP, continuous PEP, delivery of aerosolized medication, etc. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating a respiratory therapy device in accordance with principles of the present disclosure; 
         FIG. 2  is an exploded, perspective view of a respiratory therapy device in accordance with principles of the present disclosure; 
         FIG. 3A  is a perspective view of a housing portion of the device of  FIG. 2 ; 
         FIG. 3B  is a bottom view of the housing of  FIG. 3A ; 
         FIG. 4A  is a longitudinal, cross-sectional view of the housing of  FIG. 3A  taken along a patient supply inlet; 
         FIG. 4B  is a rear, perspective view of a leading portion of the housing of  FIG. 3A ; 
         FIG. 4C  is a longitudinal, cross-sectional view of the housing of  FIG. 3A  taken along a drive supply inlet; 
         FIG. 5A  is an exploded, perspective view of a drive mechanism portion of the device of  FIG. 2 ; 
         FIG. 5B  is a perspective view of the drive mechanism of  FIG. 5A  upon final assembly; 
         FIG. 6A  is a perspective view illustrating partial assembly of the device of  FIG. 2 ; 
         FIG. 6B  is a longitudinal, cross-sectional view of the device of  FIG. 2  upon final assembly, taken along a patient supply inlet; 
         FIGS. 7A and 7B  illustrate use of the device of  FIG. 2  in a passive mode; 
         FIGS. 8A-8C  illustrate use of the device of  FIG. 2  in an active mode; 
         FIG. 9  is an exploded, perspective view of an alternative respiratory therapy device in accordance with principles of the present invention; 
         FIG. 10  is a front, plan view of a trailing housing portion of the device of  FIG. 9 ; 
         FIG. 11  is a perspective, cutaway view of a portion of the device of  FIG. 9  upon final assembly; 
         FIG. 12  is a exploded, perspective view illustrating assembly of the device of  FIG. 9 ; 
         FIG. 13A  is a perspective view of the device of  FIG. 9 ; 
         FIG. 13B  is a longitudinal, perspective view of the device of  FIG. 9 ; 
         FIGS. 14A and 14B  illustrate use of the device of  FIG. 9  in which airflow passes from a patient inlet to a chamber; 
         FIGS. 15A and 15B  illustrate use of the device of  FIG. 9  in which airflow is obstructed from a patient inlet to a chamber; 
         FIG. 16  is a simplified, side sectional view of an alternative respiratory therapy device in accordance with principles of the present disclosure; 
         FIG. 17  is an exploded, perspective view of another embodiment respiratory therapy device in accordance with principles of the present disclosure; 
         FIG. 18A  is a longitudinal, cross-sectional view of the device of  FIG. 17 ; 
         FIG. 18B  is an enlarged view of a portion of  FIG. 18A ; 
         FIGS. 19A and 19B  illustrate use of the device of  FIG. 17 ; 
         FIG. 20  is a schematic illustration of an interrupter valve assembly useful with the device of  FIG. 17 ; 
         FIGS. 21A and 21B  are simplified, schematic illustrations of an alternative interrupter valve assembly useful with the device of  FIG. 17 ; 
         FIG. 22  is a longitudinal, cross-sectional view of another embodiment respiratory therapy device in accordance with principles of the present disclosure; 
         FIG. 23A  is an exploded, perspective view of another embodiment respiratory therapy device in accordance with principles of the present disclosure; 
         FIG. 23B  is a perspective, cutaway view of the device of  FIG. 23A  upon final assembly; 
         FIG. 24  is an enlarged, perspective view of an orifice assembly portion of the device of  FIG. 23A ; 
         FIG. 25  is a schematic, electrical diagram of control circuitry useful with the device of  FIG. 23A ; 
         FIGS. 26A and 26B  illustrate the device of  FIG. 23A  upon final assembly; 
         FIGS. 27A and 27B  illustrate use of the device of  FIG. 23A ; and 
         FIG. 28  is a longitudinal, cross-sectional view of another embodiment respiratory therapy device in accordance with principles of the present disclosure; 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In general terms, aspects of the present disclosure relate to respiratory therapy devices and related methods of use that are: 1) capable of operating in either of an active mode (e.g., CHFO) or a passive mode (e.g., oscillatory PEP); or 2) improved passive-only oscillatory PEP devices; or 3) improved active-only devices (CHFO and/or CPAP). As used throughout this specification, an “active” therapy device is in reference to a device that requires a separate source of positive pressure fluid to effectuate a designated respiratory therapy, whereas a “passive” therapy device is in reference to a device that delivers a designated respiratory therapy in and of itself (i.e., a separate source of positive pressure fluid is not necessary). Thus, an “active-only” therapy device is one that must be connected to a separate source of positive pressure fluid. Conversely, a “passive-only” therapy device is one that is not configured to receive pressurized fluid from a separate source. Given these definitions, several of the embodiments associated with this disclosure have base constructions appropriate for passive-only, oscillatory PEP applications, as well as modified base constructions that promote use of the device as either an oscillatory PEP therapy device or, when fluidly connected to a source of pressurized fluid, as a CHFO therapy device. In yet other embodiments, the base construction can be employed with an “active only” therapy device that provides CHFO therapy (and, in some embodiments, other respiratory therapies such as CPAP) when connected to a source of positive pressure fluid. With any of these embodiments, optional features can be included to facilitate delivery of aerosolized medication. 
     With the above understanding in mind,  FIG. 1  is a block diagram illustrating features of a respiratory therapy device  30  in accordance with some aspects of the present disclosure. In general terms, the respiratory therapy device  30  is adapted to operate in a passive mode (e.g., oscillatory PEP) and an active mode (e.g., CHFO and optionally CPAP), and generally includes a housing  32  and an interrupter valve assembly  34 . The housing  32  forms or maintains a patient inlet  36 , at least one chamber  38 , an exhaust outlet  40 , and at least one pressurized fluid supply inlet  42 . The interrupter valve assembly  34  includes at least one control port  44  and a valve body  46 . The control port(s)  44  fluidly connects the patient inlet  36  and the chamber  38 , whereas the valve body  46  is adapted to selectively obstruct or interrupt fluid flow through the control port(s)  44 . Details on the various components are provided below. In general terms, however, by controlling or operating the valve body  46  to selectively obstruct (partially or completely) the control port(s)  44 , the interrupter valve assembly  34  alters airflow/pressure characteristics to and/or from the patient inlet  36 . For example, where the supply inlet  42  is not connected to a separate source of pressurized fluid  48 , as a patient (not shown) exhales into the patient inlet  36 , the interrupter valve assembly  34  operates to periodically at least partially close the control port(s)  44 , thereby establishing a resistance to airflow or back pressure in the patient inlet  36 . This periodic back pressure, in turn, provides an oscillatory PEP therapy. In addition, when the supply inlet  42  is fluidly connected to the pressurized fluid source  48 , the interrupter valve assembly  34  operates to periodically at least partially interrupt fluid flow from the supply inlet  42  to the patient inlet  36 . This interrupted supply of pressure toward the patient serves as a CHFO therapy. As described below, the device  30  can optionally include features that selectively disable all or a portion of the interrupter valve assembly  34  in conjunction with the supply of pressurized fluid to the supply inlet  42  in providing a CPAP therapy (either along or simultaneous with CHFO therapy). 
     In light of the above, the respiratory therapy device  30  provides both active and passive modes of operation, allowing the patient (not shown) to receive oscillatory PEP treatments with the device  30  at virtually any location, as well as CHFO treatments (and optionally other active treatments such as CPAP) when the patient is at a location at which the pressurized fluid source  48  is available. The respiratory therapy device  30  can further be configured to facilitate additional respiratory therapy treatments, such as delivery of aerosolized medication (for example via a nebulizer  50 ). The nebulizer  50  can be connected to a port (not shown) provided by the housing  32 , or can include an appropriate connection piece (e.g., T-connector or line) that is fluidly connected to the housing  32  (e.g., to the patient inlet  36 ) when desired. Finally, while the pressurized fluid source  48  is shown apart from the housing  32 , in other embodiments, the pressurized fluid source  48  can be attached to, or carried by, the housing  32  (e.g., a pressurized canister mounted to the housing  32 ). 
     With the above in mind, the respiratory therapy device  30  can assume a variety of forms capable of operating in a passive mode (e.g., oscillatory PEP therapy) and an active mode (e.g., CHFO therapy). One embodiment of a respiratory therapy device  60  providing these features is shown in  FIG. 2 . The therapy device  60  generally includes a housing  62  (referenced generally) and an interrupter valve assembly  64  (referenced generally). The housing  62  includes a leading section  66 , a trailing section  68 , and an end plate  69 . The leading section  66  defines a patient inlet  70 , whereas the trailing section  68  defines a first chamber  72 , a second chamber (hidden in the view of  FIG. 2 ), an exhaust outlet (hidden in  FIG. 2 ), and one or more supply inlets  74 . The interrupter valve assembly  64  includes a plate  76  forming one or more control ports  78  (e.g., the control ports  78   a ,  78   b ), a valve body  80 , and a drive mechanism  82 . Details on the various components are provided below. In general terms, however, the drive mechanism  82  is retained within the second chamber of the housing  62  and is assembled to the valve body  80  for causing rotation thereof. The valve body  80 , in turn, is located in close proximity to the control ports  78  such that rotation of the valve body  80  selectively opens and closes (e.g., partial or complete obstruction) the control ports  78  relative to the first chamber  72  and the patient inlet  70 . Finally, the supply inlet(s)  74  are fluidly connected to distribution points within the housing  62 . During use, and in a passive mode of operation, the therapy device  60  generates oscillatory PEP via operation of the drive mechanism  82  in response to the patient&#39;s exhaled breath. In addition, the therapy device  60  provides an active mode of operation in which the interrupter valve assembly  64  causes delivery of CHFO fluid flow to the patient inlet  70  in acting upon positive fluid flow from the supply inlet(s)  74 . In this regard, a control means  84  (referenced generally) can be provided that facilitates operation of the therapy device  60  in a desired mode. 
     The housing  62  is shown in greater detail in  FIGS. 3A and 3B  upon final assembly. The housing  62  is generally sized and shaped for convenient handling by a patient, with the leading section  66  forming a mouthpiece  86  sized for placement in the patient&#39;s mouth and through which the patient&#39;s respiratory cycle interacts with the patient inlet  70 . The mouthpiece  86  can be integrally formed with one or more other component(s) of the housing  62 , or can be separately formed and subsequently assembled thereto. 
     The housing  62  can form or define fluid flow features in addition to the supply inlets  74 . For example, and as best shown in  FIG. 3A , the trailing section  68  forms a slot  90  as part of the control assembly  84  ( FIG. 2 ). As described below, the control assembly  84  can assume a variety of forms, but in some embodiments includes a body slidably disposed with the slot  90 . With alternative constructions, however, the slot  90  can be eliminated. 
     Relative to the top perspective view of  FIG. 3A , the housing  62  can further form first and second relief port arrangements  92 ,  94 . A third relief port arrangement  96  can also be provided as shown in the bottom view of  FIG. 3B . Finally, as best shown in  FIG. 2 , a fourth relief port arrangement  98  is provided within an interior of the housing  62 . Operation of the therapy device  60  in connection with the relief port arrangements  92 - 98  is described in greater detail below. In general terms, however, the relief port arrangements  92 - 98  each include one or more apertures  99 , and are adapted to maintain a valve structure (not shown), such as a one-way umbrella valve, that permits fluid flow into or out of the aperture(s)  99  of the corresponding port arrangement  92 - 98  in only a single direction. As such, the relief port arrangements  92 - 98  can assume a variety of configurations differing from those illustrated. Similarly, additional relief port arrangements can be provided, and in other embodiments one or more of the relief port arrangements  92 - 98  can be eliminated. 
     Returning to  FIG. 2 , the supply inlets  74 , otherwise carried or formed by the housing  62 , include, in some embodiments, first and second patient supply inlets  74   a ,  74   b , as well as a drive supply inlet  74   c . The patient supply inlets  74   a ,  74   b  are fluidly connected to first and second nozzles  100   a ,  100   b , respectively, each positioned to direct fluid flow toward a corresponding one of the control ports  78   a ,  78   b  (otherwise formed by the plate  76 ). A relationship of the nozzles  100   a ,  100   b  and the control ports  78   a ,  78   b  relative to the internal features of the housing  62  is provided below. It will be understood at the outset, however, that while two of the control ports  78   a ,  78   b  are shown and described, in other embodiments, one or three (or more) control ports are also acceptable. Similarly, a nozzle/patient supply inlet need not be provided for each of the control ports  78   a ,  78   b  (e.g., the patient supply inlet  74   b /nozzle  100   b  can be eliminated), or two or more supply inlet/nozzles can be directed toward a single one of the control ports  78 . Even further, two or more supply inlets  74  can be fluidly associated with a single nozzle  100 . 
     With the above in mind,  FIG. 4A  is a longitudinal cross-sectional view of the housing  62  upon final assembly taken through the first patient supply inlet  74   a . The leading portion  66 , the trailing portion  68  and the end plate  69  are generally assembled to one another as shown. As a point of reference, the view of  FIG. 4A  further illustrates the control means  84  in an open position relative to the housing  62 , and reflects that the plate  76  can be an integral component of the housing  62 . Regardless, the housing  62  is shown in  FIG. 4A  as defining the first chamber  72 , as well as a second chamber  101 , and an exhaust chamber  102 . The first chamber  72  is defined, in part, by the plate  76  and an intermediate wall  104 , with the plate  76  fluidly separating the patient inlet  70  from the first chamber  72 . In this regard, the patient inlet  70  is fluidly connected to the first chamber  72  via the control ports  78  (it being understood that only the first control port  78   a  is visible in  FIG. 4A ). The first chamber  72  is separated from the second chamber  101  by the intermediate wall  104 , with fluid connection between the chambers  72 ,  101  being provided by a passage  106 . As described in greater detail below, the passage  106  can be fluidly closed via operation of the control means  84 . Regardless, the second chamber  101  is fluidly connected to the exhaust chamber  102  via an outlet opening  108 . The first chamber  72  is also fluidly connected to the exhaust chamber  102 , via the fourth relief port arrangement  98 . As a point of reference,  FIG. 4A  reflects that a one-way valve structure  110  is associated with the fourth relief port  98  and is configured such that fluid flow can only occur from the first chamber  72  to the exhaust chamber  102 . Finally, the exhaust chamber  102  terminates at an exhaust outlet  112  that is otherwise open to ambient. 
     With the above conventions in mind, the first nozzle  100   a  is positioned within the first chamber  72 , and includes or defines an inlet end  114  and an outlet end  116 . The inlet end  114  is fluidly connected to the first patient supply inlet  74   a  such that fluid flow through the first patient supply inlet  74   a  is directed toward the outlet end  116 . The outlet end  116 , in turn, is aligned with the first control port  78   a  so as to direct fluid flow from the first nozzle  100   a  to the first control port  78   a . In some embodiments, the first nozzle  100   a  tapers in diameter from the inlet end  114  to the nozzle end  116 , such that a jet-like fluid flow from the first patient supply inlet  74   a  to the first control port  78   a  is established. In this regard, ambient air can be entrained into the fluid flow from the nozzle  100   a  (as well as the nozzle  100   b ) via the second relief port arrangement  94 . A one-way valve structure  118  is illustrated in  FIG. 4A  as applied to the relief port arrangement  94 , and dictates that ambient air can only enter the first chamber  72  (and thus the nozzle  100  fluid flow). Though not shown, operation of the valve structure  118  can be further controlled by a control mechanism that serves to selectively maintain the valve structure  118  in a closed state (e.g., during a passive mode of operation as described below). In other embodiments, entrained ambient airflow within the first chamber  72  can be provided in a different manner (e.g., not including the relief port arrangement  94 ), or can be eliminated. 
     Regardless of whether ambient air is introduced into the first chamber  72 , a gap  120  (referenced generally) is established between the outlet end  116  and the plate  76  (and thus the first control port  78   a ). As described in greater detail below, the gap  120  is sized to facilitate assembly and movement of the valve body  80  ( FIG. 2 ). Though not shown, the second patient supply inlet  74   b /second nozzle  100   b  ( FIG. 2 ) has a similar construction and relationship relative to the plate  76 /second control port  78   b . Thus, and as best shown in  FIG. 4B , the first patient supply inlet  74   a /nozzle  100   a  directs positive pressure fluid from a separate source toward the first control port  78   a , and the second patient supply inlet  74   b /nozzle  100   b  directs positive pressure fluid toward the second control port  78   b.    
     The drive supply inlet  74   c  ( FIG. 2 ) is similarly fluidly connected to an interior of the housing  62 . In particular, the drive supply inlet  74   c  is fluidly connected to the second chamber  101  as shown in  FIG. 4C . As described in greater detail below, a portion of the drive mechanism  82  ( FIG. 2 ) is retained within the second chamber  101 , with fluid flow from the drive supply inlet  74   c  serving to actuate or drive the drive mechanism  82  during an active mode of operation. 
     Returning to  FIG. 2 , the interrupter valve assembly  64  again includes the valve body  80  that is driven by the drive mechanism  82 . In some embodiments, the valve body  80  has a propeller-like construction, and includes a base  130 , a first valve plate segment  132 , and a second valve plate segment  134 . The base  130  is configured for assembly to a corresponding portion of the drive mechanism  82  as described below. The plate segments  132 ,  134  extend in a radial fashion from the base  130 , and each have a size and shape commensurate with a size and shape of a corresponding one the control ports  78   a ,  78   b . For example, a size and/or shape of the valve plate segments  132 ,  134  can be identical, slightly smaller or slightly larger than a size and/or shape of the control ports  78   a ,  78   b . Further, in some embodiments, a circumferential position of the plate segments  132 ,  134  relative to the base  130  corresponds with that of the control ports  78   a ,  78   b  such that when the base  130  is centrally positioned between the control ports  132 ,  134 , the control port  78   a ,  78   b  can be simultaneously obstructed by the plate segments  132 ,  134 . Thus, with the one embodiment of  FIG. 2 , the control ports  78   a ,  78   b  are symmetrically opposed, and the valve plate segments  132 ,  134  are similarly oriented. Alternatively, a position of the valve plate segments  132 ,  134  can be spatially offset relative to a position of the control ports  78   a ,  78   b ; with this alternative construction, the control ports  78   a ,  78   b  are not simultaneously obstructed during movement of the valve body  80 . 
     While the valve body  80  is shown as including two of the valve plate segments  132 ,  134 , any other number, either greater or lesser is also acceptable, and the number of plate segment(s)  132 ,  134  provided need not necessarily equal the number of control ports  78 . In other embodiments, for example, the valve body  80  is configured and positioned so as to fluidly interface with only one of the control ports  78  as described below. Even further, the valve body  80  can have configurations differing from the propeller-like construction shown. Regardless, the valve body  80  is constructed such that all of the control port(s)  78  can simultaneously be obstructed (e.g., completely blocked or less than completely blocked) by the valve body  80  in some embodiments. 
     The drive mechanism  82  is shown in greater detail in  FIG. 5A . In some embodiments, the drive mechanism  82  is akin to a reverse roots blower device and includes first and second lobe assemblies  140 ,  142 , and first and second gears  144 ,  146 . The lobe assemblies  140 ,  142  can be identical, with the first lobe assembly  140  including a lobe body  150  and a shaft  152 . The lobe body  150  includes three longitudinal lobe projections  154 , adjacent ones of which are separated by a valley  156 . Although three of the lobe projections  154 /valleys  156  are illustrated in  FIG. 5A , any other number is also acceptable; however, preferably at least two of the lobe projections  154 /valleys  156  are provided. Regardless, the shaft  152  is, in some embodiments, coaxially mounted within the lobe body  150 , extending from a first end  158  to a second end  160 . The first end  158  is sized for assembly to the valve body base  130  ( FIG. 2 ), whereas the second end  160  is sized for assembly to the first gear  144 . Other constructions are also contemplated such as integrally molding or forming two or more of the lobe body  150 , shaft  154 , and/or gear  140 . The second lobe assembly  142  is similarly constructed, and generally includes a lobe body  162  coaxially maintained by a shaft  164  that in turn is sized for assembly to and/or formed as part of the second gear  146 . 
     As shown in  FIG. 5B , the lobe bodies  150 ,  162  are configured for meshed engagement (e.g., one of the lobe projections  154  of the second lobe body  162  nests within one of the valleys  156  of the first lobe body  160 ), as are the first and second gears  144 ,  146  (it being understood that upon final assembly meshed engagement between the lobe bodies  150 ,  162  and between the gears  144 ,  146  is simultaneously achieved). With this construction, then, the lobe assemblies  140 ,  142  rotate in tandem, but in opposite directions (e.g., relative to the orientation of  FIG. 5B , clockwise rotation of the first lobe body  150  translates into counterclockwise rotation of the second lobe body  162 ). The shafts  152 ,  164  are affixed to the corresponding lobe body  150 ,  162 , respectively, such that rotation of the lobe bodies  150 ,  162  is translated directly to the gears  144 ,  146 , respectively, via the shafts  152 ,  164 . Thus, the gears  144 ,  146  serve to maintain a desired intermeshing relationship between the lobe bodies  150 ,  162 . With the reverse roots blower configuration of the drive mechanism  82 , a relatively small force (e.g., fluid flow) is required to initiate and maintain movement of the lobe assemblies  140 ,  142  at a desired rotational speed. In other embodiments, the number of lobe projections  154  can be increased so that the lobe bodies  150 ,  162  effectively interface as gears such that the gears  144 ,  146  can be eliminated. Regardless, upon final assembly, rotation of the first lobe assembly  140  translates into rotation of the valve body  80 . 
     Assembly of the interrupter valve assembly  64  to the housing  62  is partially shown in  FIG. 6A . In particular, the valve body  80  is maintained immediately adjacent the nozzles  100   a ,  100   b  via the shaft  152  that otherwise extends into the first chamber  72 . The shaft  164  of the second lobe assembly  142  (referenced generally in  FIG. 6A , shown in greater detail in  FIG. 5A ) also extends into, and is supported at, the first chamber  72  (it being understood that the opposite end of each of the shafts  152 ,  164  is also supported, for example at or by the end plate  69  ( FIG. 2 )). As shown in  FIG. 6B , that otherwise is a longitudinal cross-sectional view taken through the first patient supply inlet  74   a , the first lobe body  150  is maintained within the second chamber  101 , as is the second lobe body  162  (hidden in the view of  FIG. 6B ). The shaft  152  maintains the valve body  80  such that the valve plate segments  132 ,  134  (it being understood that the second plate segment  134  is hidden in the view of  FIG. 6B ) are located in the gap  120  between the outlet end  116  of the first nozzle  100   a  and the plate  76  (as well as between the second nozzle  100   b , that is otherwise hidden in the view of  FIG. 6B , and the plate  76 ). With rotation of the valve body  80  (via the drive mechanism  82 ), the valve plate segments  132 ,  134  repeatedly obstruct and “open” the control ports  78  relative to the first chamber  72 . In other words, the interrupter valve assembly  64  (referenced generally in  FIG. 6B ) operates to periodically stop or substantially stop fluid flow between the patient inlet  68  and the first chamber  72  as described below. While the valve body  80  has been described as being assembled to the first shaft  152 , in other embodiments, the second shaft  164  rotates the valve body  80 . In other embodiments, each of the shafts  152 ,  164  can maintain a valve body. 
     With the above understanding in mind, forced movement of the drive mechanism  82  can occur in one of two manners that in turn are a function of whether the device  60  is operating in a passive mode (e.g., oscillatory PEP) or an active mode (e.g., CHFO). For example, in the passive mode, the respiratory therapy device  60 , and in particular the drive mechanism  82 , operates solely upon the patient&#39;s exhaled air or breath. In this regard, and with reference to  FIGS. 2 and 6B , in the passive mode, the control means  84  is positioned such that the passage  106  is open and fluidly connects the first and second chambers  72 ,  101 . In some embodiments, the control means  84  includes a tab  166  slidably positioned within the slot  90 ; in the “open” state of  FIGS. 2 and 6B , the tab  166  is retracted from the slot  90 . The control means  84  can assume a wide variety of other forms also capable of selectively opening or closing the passage  106 . The supply inlets  74   a - 74   c  are fluidly closed or otherwise fluidly isolated from any external positive pressure fluid source (e.g., the pressurized fluid source  48  of  FIG. 1  is disconnected from the respiratory therapy device  60 ; fluid flow from the pressurized fluid source  48  is diverted from the supply inlets  74   a - 74   c ; etc.). To this end, in some embodiments the supply inlets  74   a - 74   c  can be exteriorly closed (for example, by a cap assembly (not shown)). 
     With the therapy device  60  configured as described above, the passive mode of operation can entail the mouthpiece  86  (or other patient interface piece (not shown) otherwise attached to the mouthpiece  86 ) is inserted into the patient&#39;s mouth, and the patient being prompted to breathe through the therapy device  60 . During an inspiratory phase of the patient&#39;s breathing cycle, ambient air is readily drawn into the housing  62  via the third relief port arrangement  96  (that otherwise includes a one-way valve structure  170  ( FIG. 6B ) controlling airflow therethrough). Thus, the patient can easily and readily inhale air. 
     During the expiratory phase, exhaled airflow is directed from the patient/mouthpiece  86 , through the patient inlet  68 , and toward the plate  76 . The exhaled air can fluidly pass or flow from the patient inlet  68  to the first chamber  72  via the control ports  78  when the control ports  78  are otherwise not completely obstructed by the valve body  80  (and in particular the valve plate segments  132 ,  134 ). An example of this relationship is shown in  FIG. 7A  whereby the valve body  80  has been rotated such that the plate segments  132 ,  134  are “away” from the control port  78   a  (as well as the control port  78   b  (hidden in the view of  FIG. 7A )). Thus, the exhaled air flows through the control ports  78  and into the first chamber  72  (represented by arrows in  FIG. 7A ). 
     When the airflow into the first chamber  72  is at a pressure below the opening pressure of a valve structure  172  associated with the fourth relief port arrangement  98 , the apertures  99  of the relief port arrangement  98  remain fluidly closed, and all of the airflow through the first chamber  72  flows into the second chamber  101  via the passage  106  (shown by arrows in  FIG. 7A ). Conversely, where the pressure within the first chamber  72  is above the bypass pressure associated with the valve structure  172 , the valve structure  172  “opens” to allow a portion of the airflow within the first chamber  72  to flow into the exhaust chamber  102 . In this manner, the pressure drop across the second chamber  101  remains approximately equal with the opening pressure associated with the valve structure  172 . Alternatively, other valving and/or flow dimensions can also be employed 
     Airflow from the first chamber  72  into the second chamber  101  (via the passage  106 ) serves to drive the drive mechanism  82 . In particular, airflow within the second chamber  101  acts upon the lobe assemblies  140 ,  142  (the lobe assembly  142  being hidden in  FIG. 7A ), causing operation thereof as a rotary positive blower. In general terms, and with additional reference to  FIG. 5B , airflow through the second chamber  101  causes the lobe bodies  150 ,  162  to rotate, with airflow flowing through or between the lobe bodies  150 ,  162 , and then to the outlet opening  108 . In this regard, the lobe assemblies  140 ,  142  operate as a roots blower, creating a pressure drop across the second chamber  101 . As shown in  FIG. 7B , when the control ports  78  are periodically “covered” by the valve plate segments  132 ,  134 , airflow through the control ports  78  is restricted, creating a resistance to flow, or back pressure within the patient inlet  68 . This resistance to flow/back pressure occurs periodically (i.e., when the valve plate segments  132 ,  134  are rotated away from the control ports  78 , back pressure within the patient inlet  68  is released through the control ports  78 ). As a result, a desired oscillatory PEP effect is created. Notably, the lobe assemblies  140 ,  142  continue to rotate even as airflow through the passage  106  is periodically interrupted due to inertia. Along these same lines, the lobe assemblies  140 ,  142  can be configured to act as a fly wheel, thereby reducing sensitivity to an opening time of the control ports  78 . 
     In some embodiments, dimensional characteristics of the drive mechanism  82  are correlated with the valve body  80  and the control port(s)  78  such that a flow rate of 10 lpm at 100 Pa, the valve body  80  generates approximately 15 pulses per second at the control ports  78 , with the pressure pulses at approximately 3,000 Pa. At flow rates above 10 lpm, the valve structure  172  will open and may flutter to maintain inlet pressure to the drive mechanism  82 . The fourth relief port arrangement  98  can be configured set to flow up to 20 lpm at 100 Pa (e.g., when the valve structure  172  is “open”) so as to keep the back pressure and speed approximately consistent from 10 lpm to 30 lpm. Alternatively, however, the therapy device  60  can be configured to exhibit other operational characteristics. 
     With reference to  FIGS. 2 and 8A , in the active mode of operation, the control means  84  is operated to fluidly “close” the passage  106  (e.g., the tab  166  is fully inserted into the slot  90 ). Further, the inlets  74   a - 74   c  are fluidly connected to the pressurized fluid source  48  ( FIG. 1 ). For example, in some embodiments, a flow diverter assembly (not shown) can be employed to fluidly connect a single pressurized fluid source (e.g., positive pressure gas such as air, oxygen, etc.) to each of the supply inlets  74   a - 74   c ; alternatively, two or more fluid sources can be provided. Regardless, air, oxygen, or other gas is forced or directed into the supply inlets  74   a - 74   c . With specific reference to  FIG. 8A , fluid flow into the first patient supply inlet  74   a  is illustrated with an arrow A and is directed by the nozzle  100   a  toward the control port  78   a . Ambient air is entrained into the flow generated by the nozzle  100   a  via the second relief port arrangement  94  as previously described. In instances where the valve body  80 , and in particular the valve plate segments  132 ,  134 , does not otherwise obstruct the control port  78   a  (relative to the nozzle  100   a ), airflow continues through the control port  78   a  and into the patient inlet  68 . Though hidden in the view of  FIG. 8A , a similar relationship is established between the second patient supply inlet  74   b /second nozzle  100   b  and the second control port  78   a.    
     Conversely, and as shown in  FIG. 8B , when the control port  78   a  and the control port  78   b  (hidden in  FIG. 8B ) are obstructed or “closed” via the valve plate segments  132 ,  134 , airflow from the nozzles  100   a ,  100   b  to the patient inlet  68  is effectively stopped (it being understood that in the view of  FIG. 8B , only the first patient supply inlet  74   a /nozzle  100   a , the first control port  78   a , and the first valve plate segment  132  are visible). Once again, the drive mechanism  82  operates to continually rotate the valve body  80  relative to the control ports  78   a ,  78   b , such that positive airflow from the supply inlets  74  to the patient inlet  68  is “chopped” or oscillated so as to establish a CHFO treatment during the patient&#39;s breathing cycle (including at least the patient&#39;s inspiratory phase). 
     To better ensure positive airflow toward the patient inlet  68  (and thus the patient), the control means  84  closes the passage  106  such that all air within the first chamber  72  is forced through the control ports  78 . In this regard, the drive mechanism  82 , and in particular the lobe assemblies  140 ,  142 , are acted upon and driven via fluid flow through the drive supply inlet  74   c  as shown in  FIG. 8C . In particular, forced fluid flow from the pressurized fluid source  48  ( FIG. 1 ) enters the second chamber  101  via the drive supply inlet  74   c  and acts upon the lobe bodies  150 ,  162  as previously described. In other words, operation of the therapy device  60  in the active mode is independent of the patient&#39;s breathing. Further, during the expiratory phase of the patient&#39;s breathing cycle, pulsed gas flow from the nozzles  100   a ,  100   b  to the patient inlet  70  continues, creating an oscillatory PEP effect. As a point of reference, to minimize possible occurrences of stacked breaths, exhaled air from the patient can be exhausted from the patient inlet  70  via the first relief port arrangement  92 . For example, a one-way valve structure  174  can be assembled to the relief port arrangement  92 , operating (in the active mode) to permit airflow through the relief port arrangement  92  to occur only outwardly from the patient inlet  70 , thus freely permitting exhalation during periods when the control ports  78   a ,  78   b  are blocked. An additional control mechanism (not shown) can further be provided that fluidly “closes” the relief port arrangement  92 /valve structure  174  when the device  60  operates in the passive mode described above (i.e., all exhaled air from the patient passes through the control ports  78   a ,  78   b ). Alternatively, the device  60  can include other features (not shown) that facilitate exhausting of exhaled air from the patient inlet  70 , and/or the first relief port arrangement  92  can be eliminated. Along these same lines, in the active mode, the third relief port arrangement  96 /valve structure  170  can be permanently “closed” such that all inspiratory airflow is provided via the control ports  78   a ,  78   b.    
     While the device  60  has been described above as providing CHFO therapy via essentially identical fluid flow from both of the patient inlets  74   a ,  74   b , in other embodiments, the device  60  can be configured to provide a user with the ability to select or change the level of CHFO. For example, a mechanism (not shown) can be provided that causes fluid flow from one of the supply inlets  74   a  or  74   b  to not occur (where a lower level of CHFO is desired) and continuously “blocks” the corresponding control port  78   a  or  78   b  (e.g., the supply inlet  74   a  or  74   b  can be fluidly uncoupled from the pressure source, and a closure means (not shown) actuated relative to the corresponding control port  78   a  or  78   b ). Even further, the device  60  can be modified to incorporate three of the supply inlets/nozzles  74 / 100  and three of the control ports  78 , with respective ones of the supply inlets/nozzles  74 / 100  being selectively activated/deactivated and the corresponding control ports  78  being selectively blocked so as to provide three levels of CHFO. Alternatively, the three supply inlets  74  can merge into a single nozzle  100 , again allowing a user to select a desired CHFO level by “activating” a desired number of the supply inlets  74 . 
     In addition to the passive (e.g., oscillatory PEP) and active (e.g., CHFO) modes described above, the therapy device  60  can further be configured to provide additional forms of respiratory therapy. For example, and returning to  FIG. 1 , the nebulizer  50  ( FIG. 1 ) can be fluidly connected to (and optionally disconnected from) the patient inlet  36  for providing aerosolized medication and other treatment to the patient. With respect to the exemplary therapy device  60  of  FIG. 2 , then, the housing  62  can form or include an additional port (not shown) to which the nebulizer  50  is fluidly connected. In some embodiments, the nebulizer port is provided at or adjacent the mouthpiece  86  such that nebulizer flow is directly to the patient and is not acted upon by the interrupter valve assembly  64 . Alternatively, the nebulizer port can be formed at the end plate  69 , or at any other point along the housing between the end plate  69  and the mouthpiece  86 . In other embodiments, one or more of the inlet ports  74   a - 74   c  can serve as a nebulizer port. In yet other embodiments, the nebulizer  50  can include a connection piece that is physically attached to the mouthpiece  86 . Regardless, nebulized air can be provided during operation of the interrupter valve assembly  64  (in either passive or active modes). Alternatively, the respiratory therapy device  60  can be configured such that when in a nebulizer mode of operation, the interrupter valve assembly  64  is temporarily “locked” such that the valve body  80  does not rotate and the valve plate segments  132 ,  134  do not obstruct the control ports  78 . 
     Alternatively or in addition, the therapy device  60  can be adapted to provide CPAP therapy (with or without simultaneous aerosolized drug treatment) when desired by fluidly connecting the pressurized fluid source  48  ( FIG. 1 ) to one or both of the patient supply inlets  74   a ,  74   b , while again “locking” the interrupter valve assembly  64 . In particular, the interrupter valve assembly  64  is held in a locked position whereby the valve body  80  does not rotate, and the control ports  78   a ,  78   b  are not obstructed by the valve plate segments  132 ,  134  such that positive airflow to the patient occurs continuously. For example, and with reference to  FIGS. 5A and 8A , one or more mechanisms can be provided that, when actuated, decouple the first drive shaft  152  from the first lobe body  150  (so that the drive shaft  152  does not rotate with rotation of the lobe body  150 ), and retains the valve body  80  in the “open” position of  FIG. 8A  (e.g., magnet, body that captures one or both of the valve plate segments  132 ,  134 , etc.). Along these same lines, the device  60  can be modified to deliver a constant, baseline pressure CPAP therapy with or without simultaneous CHFO treatment. For example, the interrupter valve assembly  64  can be configured such that the valve body  80  only affects fluid flow from the first supply inlet  74   a , whereas fluid flow from second supply inlet  74   b  is continuously supplied to the patient inlet  70 . With this approach, the second supply inlet  74   b  provides a specific, baseline pressure (e.g., 5 cm water) as CPAP therapy, whereas the interrupter valve assembly  64  acts upon fluid flow from the first supply inlet  74   a  in creating a CHFO effect as described above. In this regard, the interrupter valve assembly  64  can be “locked” as described above during periods where CHFO therapy is not desired. In yet another, related embodiment, the device  60  can be configured to provide a varying, selectable level of CPAP. For example, a mechanism (not shown) can be included that partially restricts (on a continuous basis) the inlet end  114  ( FIG. 4A ) and/or the exit end  116  ( FIG. 4A ) of the nozzle(s)  100 , or the corresponding supply inlet  74 , a desired extent (thus dictating a level of delivered CPAP). Alternatively, a controlled leak can be introduced into the system (e.g., a relief port arrangement and corresponding control valve that exhausts to ambient can be provided at one or both of the patient inlet  70  and/or the first chamber  72 ). Even further, one or both of the patient inlets  74  can be selectively “activated” to provide CPAP therapy as described above (it being understood that the level of CPAP will be greater where fluid flow is provided through both of the patient inlets  74  as compared to just one of the patient inlets  74 ). 
     In yet other embodiments, the device can be configured to optionally provide a continuous PEP therapy in the passive mode. In particular, the interrupter valve assembly  64  is “locked” in an open state as previously described, and the supply inlets  74  are disconnected from the pressurized fluid source  48  ( FIG. 1 ). As a result, the control ports  78  serve as flow restrictors to exhaled air, thus creating or delivering the PEP effect. 
     Regardless of whether the additional modes of operation are provided, the therapy device  60  provides a marked advantage over previous designs by being operable in both the passive and active modes. For example, a patient can be given the therapy device  60  immediately following surgery, admission to the caregiver&#39;s facility (e.g., hospital), etc., and instructed to use the therapy device  60  in the passive mode. This allows the patient to begin receiving oscillatory PEP therapy treatments immediately. Subsequently, upon observation (x-rays, breath sounds, blood analysis, etc.) by the caregiver that a more aggressive oscillatory therapy is required to aide with airway clearance and/or airway expansion, the therapy device  60  can then be connected to a pressurized source (e.g., the pressurized fluid source  48  of  FIG. 1 ) and switched to the active mode. Following the active treatment, the therapist can leave the therapy device  60  with a patient to allow the patient to continue the passive therapy without the caregiver needing to be present. In other words, the patient can continue to use the same therapy device  60  at virtually any location away from the caregiver&#39;s facility. 
     Although the respiratory therapy device  60  has been described as providing both passive and active modes of operation, in other embodiments in accordance with the present disclosure, similar principles of operation can be employed in a passive-only or oscillatory PEP device (that otherwise interacts with the patient&#39;s breathing). For example, an alternative embodiment respiratory therapy device  186  is shown in exploded form in  FIG. 9 . The therapy device  186  is similar in many respects to the respiratory therapy device  60  ( FIG. 2 ) previously described, and includes a housing  188  (referenced generally) and an interrupter valve assembly  190 . The housing  188  includes a leading section  192 , an intermediate plate  194 , a trailing section  196 , and an end plate  198 . The interrupter valve assembly  190  includes one or more control ports  200   a ,  200   b , a valve body  202 , and a drive mechanism  204 . As described in greater detail below, the drive mechanism  204  rotates the valve body  202  in response to exhaled airflow from the patient to periodically obstruct or close the control ports  200   a ,  200   b.    
     The leading section  192  of the housing  188  includes a tapered mouthpiece  208 , and forms or defines a patient inlet  210 , whereas the trailing section  196  forms a first chamber  212 . The plate  194  separates the patient inlet  210  and the first chamber  212 , and forms the one or more control ports  200   a ,  200   b . As with previous embodiments, while two of the control ports  200   a ,  200   b  are shown, any other number, either lesser or greater, is also acceptable. Regardless, fluid flow between the patient inlet  210  and the first chamber  212  is via the control port(s)  200   a ,  200   b.    
     The trailing section  196  further forms a second chamber  220  and, in some embodiments, an exhaust chamber (hidden in the view of  FIG. 9 ). The second chamber  220  is sized to receive a corresponding portion of the drive mechanism  204  as described below, and is fluidly isolated from the first chamber  212  by an intermediate wall  222 . In this regard, and as best shown in  FIG. 10 , the intermediate wall  222  forms a passage  224  through which fluid flow from the first chamber  212  ( FIG. 9 ) to the second chamber  220  (referenced generally in  FIG. 10 ) can occur. In addition, the intermediate wall  222  defines first and second holes  226   a ,  226   b  sized to receive corresponding components of the drive mechanism  204  as described below. Finally, and returning to  FIG. 9 , the end plate  198  is adapted for assembly to the trailing section  196 , and serves to close the second chamber  220 . As shown, the end plate  198  can form grooves  228  sized to rotatably retain corresponding components of the drive mechanism  204  as described below. 
     The valve body  202  is similar to the valve body  80  ( FIG. 2 ) previously described, and in some embodiments includes a base  230 , a first valve plate segment  232 , and a second valve plate segment  234 . The valve plate segments  232 ,  234  are shaped and sized in accordance with the control ports  200   a ,  200   b  such that when aligned, the valve plate segments  232 ,  234  can simultaneously obstruct or “block” the control ports  200   a ,  200   b . Regardless, the valve plate segments  232 ,  234  extend radially from the base  230  that is otherwise configured for affixment to a corresponding component of the drive mechanism  204 . 
     The drive mechanism  204  is akin to a reverse roots blower assembly, and includes first and second lobe assemblies  240 ,  242 , and first and second gears  244 ,  246 . The lobe assemblies  240 ,  242  each include a lobe body  250   a ,  250   b  coaxially mounted to, or integrally formed with, a shaft  252   a ,  252   b , respectively. The shafts  252   a ,  252   b , in turn, are assembled to, or integrally formed with, a respective one of the gears  244  or  246 , with the valve body  202  being mounted to the shaft  252   a  of the first lobe assembly  240 . Upon final assembly, the lobe bodies  250   a ,  250   b  interface with one another in a meshed fashion, as do the gears  244 ,  246 . 
     With initial reference to  FIG. 11 , assembly of the respiratory therapy device  186  includes placement of the lobe bodies  250   a ,  250   b /gears  244 ,  246  within the second chamber  220  defined by the housing  188 . As shown, the shafts  252   a ,  252   b  extend from the second chamber  220  and into the first chamber  212 . The valve body  202  is assembled to the shaft  252   a  of the first lobe assembly  240  (or the shaft  252   b  of the second lobe assembly  242 ), and is thus located with the first chamber  212 . The intermediate wall  222  serves to fluidly isolate the first and second chambers  212 ,  220 , except at the passage  224 . 
     The intermediate plate  194  and the leading section  192  are then assembled to the trailing section  196  as shown in  FIG. 12  (it being understood that in some embodiments, the leading section  192  and the plate  194  can be integrally formed). In particular, upon assembly of the leading section  192 /plate  194 , the valve body  202  is associated with the control port(s)  200   a ,  200   b . For example, the valve body  202  is positioned such that the valve plate segments  232 ,  234  selectively align with respective ones of the control ports  200   a ,  200   b  with rotation of the valve body  202 .  FIG. 13A  illustrates the therapy device  186  upon final assembly. 
     A relationship of the various components of the therapy device  186  are best shown in the cross-sectional view of  FIG. 13B . Once again, the patient inlet  210  is fluidly connected to the first chamber  212  via the control ports  200   a ,  200   b  (it being understood that only the first control port  200   a  is visible in  FIG. 13B ). The valve body  202  is maintained in the first chamber  212  such that the valve plate segments  232 ,  234  (it being understood that only the first valve plate segment  232  is seen in the view of  FIG. 13B ) are selectively aligned with the control ports  200   a ,  200   b  so as to obstruct fluid flow between the patient inlet  210  and the first chamber  212 . The first chamber  212  is fluidly connected to the second chamber  220  via the passage  224 . The second chamber  220  maintains the lobe assemblies  240 ,  242  (it being understood that only the first lobe assembly  240  is visible in the view of  FIG. 13B ). Further, the second chamber  220  is fluidly connected to an exhaust chamber  254  via an outlet opening  256 . The first chamber  212  is also fluidly connected to the exhaust chamber  254  via a relief port arrangement  258  to which a valve assembly  260  (e.g., a one-way, umbrella valve) is assembled. Finally, the exhaust chamber  254  is open to ambient at an exhaust outlet  262 . As a point of reference, the exhaust chamber  254  serves to minimize the opportunity for one or both of the outlet opening  256  and/or the relief port arrangement  258  to inadvertently be obstructed during use. In other embodiments, however, the exhaust chamber  254  can be eliminated. 
     During use, operation of the interrupter valve assembly  190  includes the lobe assemblies  240 ,  242  rotating in response to airflow entering the second chamber  220  as described in greater detail below. Rotation of the first lobe assembly  240  causes the valve body  202  to similarly rotate, thus periodically moving the valve plate segments  232 ,  234  into and out of alignment with corresponding ones of the control ports  200   a ,  200   b , creating an oscillatory PEP effect in the patient inlet  210  as the patient exhales. 
     For example, with reference to  FIGS. 14A and 14B , the mouthpiece  208  (or other component attached to the mouthpiece  208 , such as a nebulizer connector) is placed in the patient&#39;s mouth (not shown) and the patient performs a breathing cycle through the patient inlet  210 . During the inspiratory phase, ambient air readily enters the patient inlet  210  via a relief port arrangement  266 , the flow through which is controlled by a one-way valve structure  268  (such as an umbrella valve). During the expiratory phase, exhaled air from the patient is directed through the patient inlet  210  and toward the plate  194 . With the valve body  202  arrangement relative to the control ports  200   a ,  200   b  of  FIGS. 14A and 14B , the valve plate segments  232 ,  234  are not aligned with the control ports  200   a ,  200   b  such that the patient&#39;s exhaled air flows from the patient inlet  210  through the control ports  200   a ,  200   b , and into the first chamber  212 . This flow pattern is represented by arrows in  FIGS. 14A and 14B . Airflow within the first chamber  212  flows through the passage  224  and into the second chamber  220 , and then interacts with the lobe assemblies  240 ,  242 . In particular, airflow within the second chamber  220  causes the lobe assemblies  240 ,  242  to rotate, with the airflow then exiting the second chamber  220  (at the outlet opening  256  of  FIG. 14A ) to the exhaust chamber  254 . Air within the exhaust chamber  254  is then exhausted to the environment via the exhaust outlet  262 . 
     As shown in  FIGS. 14A and 14B , the valve structure  260  controls fluid flow through the relief port arrangement  258  between the first chamber  212  and the exhaust chamber  254 . In some embodiments, the valve structure  260  is a one-way bypass valve having a predetermined opening or bypass pressure. With this in mind, so long as airflow within the first chamber  212  is below the opening pressure of the valve structure  260 , the valve structure  260  remains closed, such that all air flows into the second chamber  220  as described above. Where, however, pressure within the first chamber  212  is above the opening pressure of the valve structure  260 , the valve structure  260  will “open” and allow a portion of the air within the first chamber  212  to bypass the second chamber  220 /lobe assemblies  240 ,  242  and flow directly into the exhaust chamber  254  via the relief port arrangement  258 . In this manner, the pressure drop across the second chamber  220  remains approximately equal to the opening pressure of the valve structure  260 . 
     With rotation of the lobe assemblies  240 ,  242  in response to exhaled air entering the second chamber  220 , the valve body  202  is caused to rotate. To account for instances in which the valve body  202  is initially aligned with control ports  200   a ,  200   b  (and thus may impede desired airflow into the second chamber  200  sufficient to initiate rotation of the lobe assembles  240 ,  242 ), means (not shown) can be provided by which a user can self-actuate movement of the valve body  282 , a valved conduit can be provided that directly fluidly connects the patient inlet  210  with the second chamber  220 , etc. Regardless, the valve plate segments  232 ,  234  will periodically be aligned with a respective one of the control ports  200   a ,  200   b  as shown, for example in  FIGS. 15A and 15B . When so-aligned, exhaled air from the patient at the patient inlet  210  is substantially prevented from passing through the control ports  200   a ,  200   b . As a result, a back pressure is generated within the patient inlet  210  that in turn is imparted upon the patient. This airflow is represented by arrows in FIGS.  15 A and  15 B. Because the valve body  202  is essentially continuously rotating in response to exhaled air, this back pressure is created on a periodic or oscillating basis. In other words, back pressure “pulses” are established within the patient inlet  210 , with the back pressure being “released” from the patient inlet  210  as the valve plate segments  232 ,  234  move away from the control ports  200   a ,  200   b . In some embodiments, the respiratory therapy device  186  is configured such that at an exhaled airflow rate of 10 lpm at 100 Pa drives the interrupter valve assembly  190  to create 15 pulses per second at the control ports  200   a ,  200   b , with the pressure pulses being at approximately 3,000 Pa. At flow rates above 10 lpm, the valve structure  260  will open and may flutter to maintain inlet pressure to the drive mechanism  204 . In related embodiments, the valve structure  260  is configured to establish flow of up to 20 lpm at 100 Pa, which substantially maintains the desired back pressure in the patient inlet  210  and a rotational speed constant in the range of 10 lpm-30 lpm. Alternatively, however, the respiratory therapy device  186  can be configured to exhibit a number of performance characteristics differing from those described above. 
     Another embodiment respiratory therapy device  280  is shown generally in  FIG. 16 , and is similar in construction to the device  60  ( FIG. 2 ) previously described. In particular, the device  280  includes a housing  282  and an interrupter valve assembly  284 . The housing  282  is akin to the housing  62  ( FIG. 2  previously described), and generally defines a patient inlet  286 , a first chamber  288 , a second chamber  290 , and supply inlets  292  (one of which is shown in  FIG. 16 ). As compared to the housing  62 , the first and second chambers  288 ,  290  are permanently fluidly isolated from one another (i.e., the notch  106  ( FIG. 4A ) is not provided). The interrupter valve assembly  284  is akin to the interrupter valve assembly  64  ( FIG. 2 ), and includes control ports  294  (one of which is shown) between the patient inlet  286  and the first chamber  288 , a valve body  296  and a drive mechanism  298 . 
     In general terms, the device  280  operates as an “active-only” configuration, whereby the ability to disconnect the pressurized fluid source  48  ( FIG. 1 ) from the supply inlets  292  and perform a manual, passive oscillatory PEP therapy is not provided. However, CHFO (and optionally CPAP) therapy is achieved as previously described in a manner representing a marked improvement over existing CHFO devices. For example, the device  280  can be directly connected to virtually any pressurized fluid source and still provide CHFO therapy (i.e., a separate “driver” unit is not required as the device  280  itself modifies incoming, constant pressure fluid flow into oscillatory flow to the patient). Similarly, and unlike existing designs, the device  280  can be modified as previously described with respect to the device  60  ( FIG. 2 ) to provide additional modes of operation such as delivery of aerosolized medication, CPAP, etc., separately or simultaneously with CHFO treatment. 
     Yet another alternative embodiment respiratory therapy device  300  in accordance with principles of the present disclosure is shown in  FIG. 17 . The respiratory therapy device  300  includes a housing  302  (referenced generally) and an interrupter valve assembly  304 . The housing  302  generally includes an outer housing portion  306  and an inner housing portion  308  that combine to define a first chamber  310  (referenced generally in  FIG. 17  relative to the outer housing portion  306 ) and a patient inlet  312 . The interrupter valve assembly  304  includes a valve body  314 , a drive mechanism  316  and a control port  318 . Details on the various components are provided below. In general terms, however, upon final assembly, the valve body  314  is selectively associated with the control port  318  (otherwise formed by the inner housing portion  308 ). The drive mechanism  316  selectively controls movement of the valve body  314  toward and away from the control port  318 , for example in response to air exhaled by a patient during an expiratory phase of a breathing cycle, so as to establish a periodic back pressure within the patient inlet  312 . This back pressure, in turn, provides an oscillatory PEP therapy to the patient. 
     The outer housing portion  306  is cylindrical and is sized to receive and maintain the inner portion  308 . With additional reference to  FIG. 18A , the outer housing portion  306  defines a first end  320 , a second end  322 , and an intermediate section  324 . The first end  320  forms a passage  326  having a diameter or major dimension commensurate with that of a corresponding segment of the inner housing portion  308  such that upon assembly, the outer portion  306  and the inner portion  308  are fluidly sealed at the first end  320 . Conversely, the second end  322  forms an opening  328  having a diameter or major dimension greater than a corresponding dimension of the inner housing portion  308  (and any other components attached thereto). With this configuration, the housing  302  is fluidly open to ambient at the second end  322 . Finally, the intermediate segment  324  similarly defines a diameter or major dimension greater than that of the inner housing portion  308  so as to define the first chamber  310  between the inner housing portion  308  and the intermediate segment  304  of the outer housing portion  306 . 
     The inner housing portion  308  includes, in some embodiments, a mouthpiece  330  and a tube  332 . The mouthpiece  330  is adapted for convenient placement within a patient&#39;s mouth (or assembly to separate component (e.g., a nebulizer connection piece) that in turn is adapted for placement on a patient&#39;s mouth and thus can have, in some embodiments, an oval-like shape as shown in  FIG. 17 . Regardless, the mouthpiece  330  is connected to the tube  332 , with the components combining to define the patient inlet  312  in the form of a continuous passage. 
     The tube  332  can assume a variety of different constructions, and includes or defines a proximal section  334  and a distal section  336 . As shown in  FIGS. 17 and 18A , the tube  332  includes an exterior shoulder  338  at the proximal section  334 . As described in greater detail below, the shoulder  338  serves as a support or fulcrum for the drive mechanism  316  upon final assembly. Regardless, the control port  318  is formed at or adjacent the distal section  336 , and establishes a fluid connection between the patient inlet  312  and the chamber  310 . While shown as being part of the inner housing portion  308 , then, the control port  318  is effectively part of the interrupter valve assembly  304 . 
     In addition to the control port  318 , the interrupter valve assembly  304  includes the valve body  314  and the drive mechanism  316  as shown in  FIG. 18A . The valve body  314  is, in some embodiments, a disc having a size and shape commensurate with a size and shape of the control port  318  (e.g., the valve body  314  can have the same shape dimensions as the control port  318 , or can be larger or smaller than the control port  318 ). In some embodiments, the valve body disc  314  is sized to be slightly larger than the control port  318  to better achieve a more complete, selective obstruction of the control port  318 . As best shown in  FIG. 18B , the valve body disc  314  defines opposing first and second major surfaces  340 ,  342 . With the one embodiment of  FIG. 18B , the first surface  340  is flat. In other embodiments, however, the first surface  340  can assume a different shape, such as a hemispherical, conical, etc. Regardless, the first surface  340  is configured to generally mate with an exterior surface  344  of the inner housing portion  308  at which the control port  318  is defined. 
     Returning to  FIG. 18A , the drive mechanism  316  is, in some embodiments, akin to a beam or other cantilevered-type device, and includes a leading end  350  and a trailing end  352 . The leading end  350  is affixed to the valve body  314 , whereas the trailing end  352  is adapted for assembly to the shoulder  338  of the inner housing portion  308 . As described below, the drive mechanism  316  serves as a cantilever beam, and thus exhibits a desired stiffness for repeated, cyclical deflection. With this in mind, in some embodiments, the drive mechanism/beam  316  is formed of a steel spring, although other materials are also acceptable. 
     Finally, and as shown in  FIGS. 17-18B , in some embodiments the respiratory therapy device  300  further includes a valve assembly  354  mounted to the inner housing portion  308 . The valve assembly  354  can assume a variety of configurations, and can be akin to a one-way valve (e.g., flap or umbrella check valve). Thus, in some embodiments, the valve assembly  354  includes a frame  356  forming one or more apertures  358 , along with a valve structure  360  that selectively obstructs the apertures  358 . With this configuration, the valve assembly  354  permits ambient airflow into the tube  332 /patient inlet  312 , but restricts or prevents airflow outwardly from the tube  332 /patient inlet  312 . 
     Assembly of the respiratory therapy device  300  includes affixment of the valve assembly  354  to the distal section  336  of the inner housing portion  308 . The trailing end  352  of the drive mechanism beam  316  is assembled (e.g., welded, bonded, etc.) to the shoulder  338  of the inner housing portion  308 . As shown in  FIG. 18A , upon assembly, the drive mechanism beam  316  is substantially straight and positions or aligns the valve body  314  with or “over” the control port  318 . 
     In the neutral or resting state of  FIG. 18A , then, the valve body  314  is in highly close proximity to the control port  318  so as to overtly restrict fluid flow through the control port  318 . In some embodiments, and as best shown in  FIG. 18B , the drive mechanism  316  is configured such that with the drive mechanism beam  316  in the neutral or resting state, a slight gap  362  is established between the valve body  314  and the exterior surface  344  of the inner housing portion  308  (otherwise defining the control port  318 ). A size of the gap  362  dictates a level of pressure drop within the patient inlet  312 , with a dimension of the gap  362  having an inverse relationship to pressure drop within the patient inlet  312 . With this in mind, in some embodiments, the gap  362  is less than 0.1 inch; and in other embodiments, less than 0.08 inch, and in yet other embodiments, is less than 0.04 inch. Alternatively, however, other dimensions are also acceptable, including elimination of the gap  362 . It has surprisingly been found, for example, that where the control port  318  has a diameter on the order of 0.28 inch, the valve body  314  is a disc having a diameter on the order on 0.36 inch and a mass of 11.6 grams, where the drive mechanism beam  316  is formed of stainless steel and has a length on the order of 2.5 inches, a desired pressure drop/response of the respiratory therapy device  300  at 20 lpm flow rate is achieved with a dimension of the gap  362  being 0.011 inch. In particular, the respiratory therapy device  300  exhibited, in some embodiments, a pressure drop at 20 lpm flow rate in the range of 100-2,500 Pa. 
     During use, the therapy device  300  is provided to a patient along with instructions on desired orientation during use. In this regard, and in some embodiments, the therapy device  300  provides optimal performance when the control port  318  is spatially positioned at a “side” of the therapy device  300  as held by a patient. The oval or oblong shape of the mouthpiece  330  provides the patient with a visual clue of this desired orientation. While the therapy device  300  can operate when spatially oriented such that the control port  318  is facing “downwardly” (e.g., in the orientation of  FIGS. 18A and 18B ), or “upwardly,” an upright orientation may better account for the effects of gravity during operation of the interrupter valve assembly  304 . 
     Notwithstanding the above, operation of the therapy device  300  is described with reference to  FIGS. 19A and 19B  with the therapy device  300  in an otherwise “downward” orientation for ease of illustration. It will be understood, however, that in other embodiments, the therapy device  300  is preferably spatially held by a patient such that the control port  318 /valve body  314  is at a “side” of the therapy device as held (i.e., into the page of  FIGS. 19A and 19B ). With this in mind, following insertion of the mouthpiece  330  (or other component assembled to the mouthpiece  330 ) into the patient&#39;s mouth, the patient performs multiple breathing cycles. During the inspiratory phase, ambient airflow readily enters the patient inlet  312  via the aperture  358 /valve assembly  354 . During the expiratory phase, exhaled air from the patient is forced through the patient inlet  312  and toward the distal section  336  of the tube  332 . The valve assembly  354  prevents exhaled air from exiting the tube  332  via the apertures  358 . Instead, the exhaled airflow is directed to and through the control port  318 ; airflow exiting the control port  318  exerts a force onto the valve body  314  in a direction away from the tube  332  (and thus away from the control port  318 ), as shown by arrows in  FIG. 19A . The drive mechanism beam  316  deflects to permit movement of the valve body  314  in response to the force, pivoting at the shoulder  338 . As the valve body  314  moves away from the control port  318 , pressure drops within the patient inlet  312 , and the airflow proceeds to the chamber  310  and then to ambient environment via the opening  328 . 
     The drive mechanism beam  316  is configured to deflect only a limited extent in response to expected forces on the valve body  314  (i.e., expected airflow pressures at the control port  318  in connection with an adult patient&#39;s expiratory phase of breathing), and thus resists overt movement of the valve body  314  away from the control port  318 . In addition, as the valve body  314  is further spaced from the control port  318 , the force placed upon the valve body  314  by airflow/pressure from the control port  318  inherently decreases due to an increased area of the gap  362 . At a point of maximum deflection ( FIG. 19A ), a spring-like attribute of the drive mechanism beam  316  subsequently forces the valve body  314  back toward the control port  318 , such that the valve body  314  again more overtly obstructs airflow through the control port  318 . The drive mechanism beam  316  ultimately returns to the near-neutral position of  FIG. 19B  in which the valve body  314  substantially closes the control port  318 , and a back pressure is again established within the patient inlet  312 . The attendant force on the valve body  314  then increases, causing the drive mechanism beam  316  to again deflect as described above. This cyclical movement of the interrupter valve assembly  304  continues throughout the expiratory phase, thereby creating a periodically-occurring back pressure within the patient inlet  312 . The patient, in turn, experiences an oscillatory PEP treatment, with the patient&#39;s exhaled air serving as the sole input force to the driving mechanism beam  316 . 
     Although the respiratory therapy device  300  has been described in connection with a cantilever-type resonator interrupter valve assembly  304 , in other embodiments, a differing configuration can be employed. For example,  FIG. 20  schematically illustrates an alternative embodiment interrupter valve assembly  370  in connection with a tube  372  otherwise forming a patient inlet  373  and a control port  374 . As a point of reference, the tube  372  of  FIG. 20  is akin to the tube  332  of  FIG. 18A . Regardless, the interrupter valve assembly  370  employs a rocker-type arrangement, and includes a valve body  376  and a drive mechanism  378 . The valve body  376  is sized in accordance with a size of the control port  374  (e.g., identical, slightly smaller, or slightly larger), and is maintained or driven by the drive mechanism  378 . In this regard, the drive mechanism  378  includes an arm  380 , a support  382 , and a biasing device  384 . 
     The arm  380  maintains the valve body  376  and is pivotally mounted to the support  382  at a pivot point  386 . The arm  380  includes a first side  388  at which the valve body  376  is formed or affixed, and an opposite, second side  390 . As shown, the second side  390  is configured to provide additional mass to offset a mass of the valve body  376 . Regardless, the support  382  pivotally maintains the arm  380  and can be assembled to, or formed as part of, the tube  372 . 
     The biasing device  384  exerts a biasing force onto the valve body  376  opposite the control port  374 . In some embodiments, the biasing device  384  is a coil spring secured at a first end  392  to the valve body  376 /arm  380  and at an opposite, second end  394  to a support structure  396  (drawn generally in  FIG. 20 ). As a point of reference, in some embodiments, the support structure  396  can be formed by, or provided as part of, the outer housing portion  306  ( FIG. 18A ). 
     Regardless of exact construction, the interrupter valve assembly  370  provides a balanced rocker arrangement, with the biasing device  384  serving as a stiffness element. During use, the valve body  376  limits airflow from the patient inlet  373 /control port  374 , with the distance or gap between the valve body  376  and the control port  374  (and thus the resistance to expiratory airflow) being cyclically dictated by the biasing device  384 . Once again, as the valve body  376  approaches the control port  374 , a back pressure is created within patient inlet  373  (in conjunction with continued airflow from the patient during the expiratory phase of breathing). With this arrangement, then, an oscillatory PEP therapy can be delivered, with the interrupter valve assembly  370  operating independent of a spatial orientation of the corresponding respiratory therapy device/housing. Though not shown, an additional nebulizer port(s) can be provided with, or formed by, the housing  302  through which aerosolized medication can be delivered to the patient. 
     Yet another alternative embodiment interrupter valve assembly  400  is shown schematically in  FIGS. 21A and 21B . As best shown in  FIG. 21B , the interrupter valve assembly  400  is associated with a tube  402  that is akin to the tube  332  ( FIG. 18A ) previously described, and otherwise defines a patient inlet  404  and a control port  406 . 
     With the above conventions in mind, the interrupter valve assembly  400  includes the control port  406 , a valve body  408 , and a drive mechanism  410 . Once again, the valve body  408  is sized and shaped in accordance with the size and shape of the control port  406 , as previously described (e.g., identical, slightly larger, slightly smaller, etc.). With the embodiment of  FIGS. 21A and 21B , the drive mechanism  410  is akin to a proportional spring mass system and includes a fly wheel  412  and a biasing device  414 . The fly wheel  412  is rotatably mounted relative to the tube  402 , for example by a spindle  416 . As shown in  FIG. 21A , for example, the spindle  416  can be mounted or held by various surfaces  418   a ,  418   b  provided with a housing (not shown) of the corresponding therapy device. Regardless, the fly wheel  412  can freely rotate. 
     The biasing device  414  defines a first end  420  and a second end  422 . The first end  420  is secured to the valve body  408 , whereas the second end  422  is secured to the fly wheel  412 , for example by a finger  424  as shown in  FIG. 21A . In some embodiments, the biasing device  414  is a linear spring, but in other embodiments can take other forms, such as a coiled torsional spring. 
     Regardless of exact construction, during use the valve body  408  serves to restrict airflow from the patient inlet  404  through the control port  406 . In this regard, a level of resistance to airflow (and thus back pressure created within the patient inlet  404  during expiratory phase of a patient&#39;s breathing cycle) is a function of a gap  426  ( FIG. 21B ) between the valve body  408  and the control port  406 . The drive mechanism  410 , in turn, dictates a size or dimension of this gap. In particular, as exhaled air is directed through the control port  406 , the valve body  408  is forced away from the control port  406 , with the biasing device  414  providing a resistance to the airflow force placed upon the valve body  408 . Further, as the valve body  408  is moved away from the control port  406 , the force is translated onto the biasing device  414 , and then onto the fly wheel  412 . As a result, the fly wheel  412  slightly rotates (e.g., counterclockwise relative to the orientation of  FIG. 21B ). At a certain point, a spring force of the biasing device  414  overcomes a force of the airflow through the control port  406 , such that the biasing device  414  forces the valve body  408  back toward the control port  406 . In this regard, the fly wheel  412  serves as a guide for movement of the valve body  408 , ensuring that the valve body  408  moves back toward alignment with the control port  406 . In this manner then, a periodic back pressure is created within the patient inlet  404 , thus effectuating an oscillatory PEP therapy to the patient during the patient&#39;s expiratory phase of breathing. 
     Although the respiratory therapy device  300  ( FIG. 17 ), along with the various interrupter valve assemblies  370  ( FIG. 20 ),  400  ( FIGS. 21A ,  21 B), has been described in the context of a passive-only device (e.g., providing oscillatory PEP therapy in response to the patient&#39;s exhaled breath), in other embodiments, similar design configurations can be employed to provide a respiratory therapy device capable of operating in both a passive mode (e.g., oscillatory PEP) and an active mode (e.g., CHFO). For example,  FIG. 22  illustrates another alternative embodiment respiratory therapy device  440  in accordance with aspects of the present invention. The respiratory therapy device  440  is highly similar to the respiratory therapy device  300  ( FIG. 17 ) previously described, and includes a housing  442  and an interrupter valve assembly  444  including a first interrupter valve sub-assembly  446  and a second interrupter valve sub-assembly  448 . Once again, the housing  442  includes an outer portion  450  and an inner portion  452  that combine to define a chamber  454 . The inner portion  452  includes a mouthpiece  456  and a tube  458  that combine to define a patient inlet  460 . Further, the tube  458  forms a first control port  462  fluidly connecting the patient inlet  460  and the chamber  454 . In this regard, the first interrupter valve sub-assembly  446  is akin to the interrupter valve assembly  304  ( FIG. 17 ) previously described, and provides oscillatory back pressure within the patient inlet  460  in response to exhaled air. In other words, the first interrupter valve sub-assembly  446  operates as previously described, establishing oscillatory PEP therapy. 
     In addition to the above, the housing  442  includes a supply inlet  464  extending from the inner housing portion  452  and exteriorly from the outer housing portion  450 . The supply inlet  464  is configured for fluid connection to an external source of pressurized fluid (not shown, but akin to the pressurized fluid source  48  of  FIG. 1 ), and is fluidly connected to a second control port  466  formed by, or connected to, the tube  458 . 
     With the above in mind, the second interrupter valve sub-assembly  448  is akin to the first interrupter valve sub-assembly  446  and includes the second control port  466 , a valve body  468  and a drive mechanism  470 . The valve body  468  has a size and shape commensurate with a size and shape of the second control port  466 , such that the valve body  468  can obstruct fluid flow through the second control port  466 . Though not shown, various relief port arrangement(s) and related valve structure(s) can further be included in connection with the second interrupter valve sub-assembly  448  to ensure adequate pressure is reached to produce desired pressure pulse/volume, and/or entrainment of ambient air. 
     The drive mechanism  470  is, in some embodiments, an elongated beam having a first end  472  and a second end  474 . The first end  472  maintains the valve body  468 , whereas the second end  474  is configured for mounting to an interior shoulder  476  that in some embodiments is formed or provided by the tube  458 . 
     Upon final assembly, then, the valve body  468 /drive mechanism  470  are interiorly positioned within the tube  458 , with the valve body  468  being aligned with the second control port  466 . During use, positive airflow is established within the patient inlet  460 , with the fluid flow being directed to the second control port  466 . The second interrupter valve sub-assembly  448  operates to periodically interrupt fluid flow through the second control port  466  and into the patient inlet  460 . In particular, and as previously described, the drive mechanism beam  470  moves the valve body  468  in a cyclical fashion relative to the second control port  466 , thereby creating a varying obstruction to fluid flow into the patient inlet  460 . Thus, when operating in an active mode (i.e., when the therapy device  440  is connected to the source of pressurized fluid  48  of  FIG. 1 ), the respiratory therapy device  440  provides CHFO treatment to the patient during the patient&#39;s breathing cycle (including the inspiratory phase). Conversely, the therapy device  440  can be disconnected from the source of pressurized fluid (and the supply inlet  464  fluidly closed) and operate in the passive mode to provide oscillatory PEP therapy. Though not shown, the therapy device  440  can incorporate additional features that facilitate use of the therapy device  440  to deliver aerosolized medication, CPAP therapy (constant or variable), etc., as described above with respect to the device  60  ( FIG. 2 ). Even further, the therapy device  440  can be modified to serve as an “active-only” device, for example by eliminating the first interrupter valve sub-assembly  446 . 
     Yet another alternative embodiment respiratory therapy device  500  is shown in  FIGS. 23A and 23B . The respiratory therapy device  500  includes a housing  502  (referenced generally) and an interrupter valve assembly  504  (referenced generally). Details on the various components are provided below. In general terms, however, the housing  502  maintains the interrupter valve assembly  504 , and forms a patient inlet  506  fluidly connected to a chamber  508  via a control port  510 . The interrupter valve assembly  504  includes a valve body  512  and a drive mechanism  514  (referenced generally). During use, the drive mechanism  514  moves the valve body  512  relative to the control port  510  such that the valve body  512  variably restricts airflow through the control port  510 . In this way, a pulsed back pressure is created within the patient inlet  506 , thereby delivering an oscillatory PEP therapy. 
     The housing  502  includes an outer portion  520 , an inner portion  522 , and an orifice body  524 . The outer portion  520  provides an exterior frame contoured for convenient handling of the therapy device  500  by a user, and maintains the various components thereof. 
     The inner housing portion  522  includes a mouthpiece  526  and a tube  528 . The mouthpiece  526  is sized and shaped for convenient placement within a patient&#39;s mouth (or assembly to a separate component adapted for placement in a patient&#39;s mouth, such as a nebulizer connector piece), and can be integrally formed with the tube  528 . Regardless, the mouthpiece  526  and the tube  528  combine to define the patient inlet  506  through which airflow to and from the patient directly occurs. In this regard, the tube  528  extends from the mouthpiece  526  to a trailing side  530 . 
     With additional reference to  FIG. 24 , the orifice body  524  is assembled to, or formed as part of the tube  528  at the trailing side  530  thereof. The orifice body  524  includes a rim  532  and a wall  534 . As best shown in  FIG. 24 , the control port  510  is formed in the wall  534 . In addition, the wall  534  forms a relief port arrangement  536 , consisting of one or more apertures  538 . The relief port arrangement  536  maintains a valve structure  540  that otherwise allows airflow through the apertures  538  in only a single direction. Regardless, the rim  532  forms a slot  542  that is adjacent the control port  510 . With this configuration, a body inserted through the slot  542  can selectively obstruct all or a portion of the control port  510 . 
     Returning to  FIGS. 23A and 23B , the valve body  512  is sized for slidable insertion within the slot  542  and includes a leading segment  544  and a trailing segment  546 . The leading segment  544  is sized for slidable placement within the slot  542 , and in some embodiments has a tapered shape. Regardless, the trailing segment  546  is configured for attachment to corresponding components of the drive mechanism  514  as described below. 
     With the embodiment of  FIGS. 23A and 23B , the drive mechanism  514  is configured to operate as an EMF resonator and includes a resonator system  548  (comprised of a beam  550  and a micromotor assembly  552 ), control circuitry  554 , an actuator  556 , and a power source  558 . In general terms, the power source  558  powers the micromotor assembly  552 . In response to a user prompt at the actuator  556 , the circuitry  554  activates the micromotor  552  that in turn causes the beam  550  to resonate, in some embodiments at a natural frequency of the beam. Regardless, the beam  550  vibrates, causing the attached valve body  512  to move relative to the control port  510 . 
     The beam  550  is relatively thin and is formed from a stiff material. In some embodiments, the beam  550  is formed of steel that otherwise exhibits low damping characteristics; alternatively, other materials such as plastic, ceramic, etc., may also be employed. For example, where the beam  550  is formed of steel, it can have a thickness on the order of 0.01 inch. Where differing materials are employed, a nominal thickness of the beam  550  may be increased or decreased. 
     As described in greater detail below, during use, the beam  550  is subjected to a vibrational force, causing a leading portion  560  thereof to resonate (whereas a trailing portion  562  is held stationary). With this in mind, in some embodiments, the beam  550  is constructed (e.g., in terms of material and dimensions) so as to not only fit within a desired footprint of the housing outer portion  520 , but also to exhibit a natural frequency above a desired level such that when the micromotor assembly  552  and the valve body  512  are attached to the leading section  560 , the resultant natural frequency of the resonator system  548  will approximate a desired natural frequency. For example, in some embodiments, a desired natural frequency of the resonator system  548  (at the leading section  560  of the beam  550 ) is approximately 15 Hz. In the absence of a mass of the micromotor assembly  552  and the valve body  512 , then, the beam  550  exhibits, in some embodiments, a natural frequency well above 15 Hz (for example, on the order of 40-80 Hz). With a mass of the valve body  512  and the micromotor assembly  552  in mind, then, additional mass can be added to the beam  550  to “fine tune” the overall natural frequency of the resonator system  548  to approximate 15 Hz. Of course, in other embodiments, other frequencies exhibited by the beam  550  alone and/or in combination with the micromotor assembly  552  and the valve body  512  are also acceptable. 
     As best shown in  FIG. 23A , the micromotor assembly  552  includes a variable speed micromotor  570  that rotates an output shaft  572 . An unbalanced mass  574  is mounted to the output shaft  572 . With this configuration, then, operation of the micromotor assembly  552  generates a vibrational force load at the running frequency. The micromotor  570  can assume a wide variety of forms, and in some embodiments micromotor is a brushed, direct current (DC) motor, adapted to rotate the output shaft  572  at a rotational speed proportional to the input voltage supplied to the micromotor  570 . For example the micromotor  570  can be akin to a micromotor used in cell phone application for generating a vibrational force, for example a micromotor manufactured by Maduchi Motor Co. under the trade designation Model RF-J2WA. Regardless, the micromotor  570  is electronically connected to the circuitry  554  that in turn regulates voltage supply to the micromotor  570  from the power source  558 . 
     The control circuitry  554  is, in some embodiments, a control chip or circuit board adapted to regulate the voltage applied to the micromotor  570  and limit current to the micromotor  570  based on displacement and frequency of the valve body  512 /beam  550 . In this regard, the control circuitry  554  is adapted to monitor the beam  550 , effectively viewing the beam  550  as a capacitor. With this approach, a measurement of both displacement and frequency can be made. More particularly, the frequency measurement can be used to control the output voltage to the micromotor  570  and maintain a desired speed, while the displacement measurement can be used to shift the speed of the micromotor  570  to avoid hitting “hard” stops on the beam  550 . As a point of reference, if the beam  550  hits a “hard” stop, the beam  550  will stop oscillating and will require time to regain the correct valve opening and frequency. One exemplary schematic configuration of the control circuitry  554  is provided in  FIG. 25 . It will be understood, however, that this is but one acceptable configuration. 
     Returning to  FIGS. 23A and 23B , the actuator  556  is configured to prompt the control circuitry  554  to initiate or stop delivery of power to the micromotor  570 . In this regard, the actuator  556  can assume a variety of forms, and in some embodiments is a button or similar body projecting from the housing outer portion  520 . Alternatively, the actuator  556  can assume a variety of other forms, for example a membrane-based sensor, wireless actuator, etc. 
     Finally, the power source  558  provides appropriate power to the micromotor  570  and the control circuitry  554 . In some embodiments, the power source  558  is carried within a compartment  576  of the housing  502 , and can assume any appropriate form (e.g., one or more batteries). 
     The respiratory therapy device  500  is shown in assembled forms in  FIGS. 26A and 26B . In particular, the valve body  512  is assembled to the leading section  560  of the beam  550  such that the leading segment  544  extends away from the beam  550 . The micromotor assembly  552  is mounted to the trailing segment  546  of the valve body  512  as best shown in  FIG. 26A . In this regard, while the trailing segment  546  is adapted to receive the micromotor assembly  552 , in other embodiments, the micromotor assembly  552  can be mounted directly to the beam  550 . 
     The orifice body  524  is coupled to the trailing side  530  of the tube  528  such that the wall  534  extends across the tube  528 . As shown in  FIG. 26A , the one-way valve structure  540  is assembled to the relief port arrangement  536  so as to control fluid flow through the apertures  538 . 
     The beam  550  is then assembled to the housing  502  such that the trailing section  562  is affixed relative to the housing  502 , and the valve body  512  slidably extends within the slot  542  of the orifice body  524 . As best shown in  FIG. 26B , in a natural state of the beam  550 , the leading segment  544  of the valve body  512  partially obstructs the control port  510 . Further, and as best shown in  FIG. 26A , a slight gap  582  (referenced generally) is established between the valve body  512  and the wall  534  of the orifice body  524  (and thus the control port  510 ). 
     The power source  558  is assembled to the housing  502  as shown, and electrically connected to the control circuitry  554  and the micromotor  570 , for example via wiring (not shown). The control circuitry  554 , as well as the actuator  556 , are similarly assembled to the housing  502 . 
     During use, the micromotor assembly  552  is operated to resonate the beam  550 , and thus the valve body  512 . As indicated above, in some embodiments, the resonator system  548  (i.e., the beam  550 , micromotor  552 , and the valve body  512 ) is constructed to exhibit a natural resonation frequency approximating a desired frequency of movement of the valve body  512  relative to the control port  510 . By exciting the resonator system  548  (and thus the beam  550 ) at the selected natural frequency, the input force and function can be smaller than the force required to deflect the beam  550  alone, thus resulting in reduced power requirements. Thus, as the motor assembly  552  vibrates, the beam  550  resonates, causing the valve body  512  to move back and forth (e.g., up and down relative to the orientation of  FIG. 26B ) relative to the control port  510 . As such, with resonation of the beam  550 , the valve body  512  selectively “opens” and obstructs the control port  510  in an oscillating fashion. 
     Regardless of whether the micromotor  570  is powered, during the inspiratory phase of a patient&#39;s breathing cycle, ambient air readily enters the patient inlet  506  via the relief port arrangement  536 . During the expiratory phase (and with appropriate activation of the drive mechanism  514  via the actuator  556 ), the drive mechanism  514  causes the valve body  512  to open and close the control port  510  in an oscillating fashion. For example, and with reference to  FIG. 27A , as the beam  550  resonates downwardly (relative to the orientation of  FIG. 27A ), the valve body  512  essentially closes the control port  510  such that exhaled airflow within the patient inlet  506  cannot flow through the control port  510 . As a result, a back pressure is created within the patient inlet  506 . Conversely, and as shown in  FIG. 27B , as the beam  550  resonates upwardly (relative to the orientation of  FIG. 27B ), the valve body  512  is radially displaced from the control port  510 , such that airflow within the patient inlet  506  easily passes through the control port  510  and into the chamber  508  (and thus is exhausted to ambient). In this regard, the control circuitry  554  operates to regulate power supply to the motor assembly  570  so as to consistently resonate the beam  550  at a desired frequency (e.g., 15 Hz). Regardless, the periodic back pressure created within (and release from) the patient inlet  506  during the expiratory phase of the patient&#39;s breathing cycle effectuates an oscillatory PEP treatment for the patient. In other embodiments, one or more nebulizer port(s) (not shown) can be provided with, or formed by, the housing  502  to facilitate delivery of aerosolized medication to the patient. Similarly, a nebulizer connection piece (not shown) can be fluidly connected in-line to the mouthpiece  526 . 
     Although the respiratory therapy device  500  has been described as operating or providing only a passive mode (e.g., oscillatory PEP), in other embodiments, similar design characteristics can be employed in providing a therapy device capable of operating in both a passive mode as well as an active mode (e.g., CHFO). For example,  FIG. 28  illustrates another embodiment respiratory therapy device  600  that is highly similar to the therapy device  500  ( FIG. 22A ) previously described. More particularly, the respiratory therapy device  600  includes the housing  502  and the interrupter valve assembly  504  components as previously described, as well as a supply inlet  602 . The supply inlet  602  is adapted for fluid connection to an external source of pressurized fluid (not shown, but akin to the pressurized fluid source  48  of  FIG. 1 ), and terminates at a nozzle end  604 . As shown, the nozzle end  604  directs fluid flow from the supply inlet  602  toward the control port  510 . Further, a position of the nozzle end  604  relative to an exterior of the housing  502  allows for entrainment of ambient air into the fluid flow from the nozzle end  604 . Additional valving (not shown) can optionally be provided to prevent occurrences of stacked breaths. 
     In a passive mode of operation (i.e., the supply inlet  602  is disconnected from the pressurized fluid source), the therapy device  600  operates as previously described (e.g., during the expiratory phase of the patient&#39;s breathing cycle, the drive mechanism  514  resonates the valve body  512  relative to the control port  510  so as to establish a periodic back pressure within the patient inlet  506  in providing oscillatory PEP therapy). In an active mode of operation, positive fluid flow is forced through the supply inlet  602  and directed by the nozzle end  604  toward the control port  510 . In connection with this forced supply of airflow, the drive mechanism  514  again causes the valve body  512  to resonate relative to the control port  510 , thus cyclically interrupting fluid flow from the nozzle end  604  through the control port  510 , and thus into the patient inlet  506 . Thus, in the active mode of operation, the respiratory therapy device  600  operates to provide CHFO treatment to the patient during an entirety of the breathing cycle (including at least the inspiratory phase of breathing). Though not shown, the therapy device  600  can incorporate additional features that facilitate use thereof to delivery aerosolized medication, CPAP therapy, etc., as described above with respect to the device  60  ( FIG. 2 ). Even further, the therapy device  600  can be modified to serve as an “active-only” device, for example by providing an exhaust valve arrangement between the mouthpiece  506  and the control port  510 . 
     The respiratory therapy device of the present invention provides a marked improvement over previous designs. In some embodiments, a standalone respiratory therapy device is provided, capable of operating in a passive mode and an active mode. In the passive mode, the therapy device effectuates an oscillatory PEP treatment to the patient, and with many embodiments does so solely in response to the patient&#39;s exhaled breath. In the active mode of operation, an external source of pressurized fluid is connected to the device with the device independently affecting fluid flow from the external source to provide CHFO treatment. Unlike existing configurations, embodiments of the present disclosure providing an active mode of operation can be connected to virtually any pressurized fluid source (e.g., regulated or non-regulated wall source, home compressor, oxygen tank, a mechanical/pneumatic flow interrupter or “driver,” standalone ventilator system, etc.). In this regard, when connected to an existing flow interrupter/driver that otherwise generates pressurized fluid in pulsed form, the driver can provide the ability to “tailor” the actual therapy delivered to a particular patient. In yet other embodiments, the respiratory therapy device provides passive therapy (e.g., oscillatory PEP) in a manner not previously considered. In yet other embodiments, an improved “active-only” therapy device is provided. Further, with any of the embodiments, additional therapies can be provided, such as CPAP and/or nebulizer treatments. 
     Although the present invention has been described with respect to preferred embodiments, workers skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the present invention.