Patent Publication Number: US-2021170119-A1

Title: Medication delivery system with mask

Description:
This application is a continuation of U.S. application Ser. No. 15/600,039, filed May 19, 2017, which application claims the benefit of U.S. Provisional Application No. 62/338,798, filed May 19, 2016, and U.S. Provisional Application No. 62/366,327, filed Jul. 25, 2016, the entire disclosures of which are hereby incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This application is directed to devices and systems for use in the field of pulmonary aerosol drug delivery via a metered dose inhaler (MDI) and valved holding chamber (VHC), and in particular devices and systems for improving patient adherence to their medication regimen and providing feedback to the user, prescriber or payer regarding proper inhalation technique and end of treatment. 
     BACKGROUND 
     VHC and MDI systems are typically used to treat such conditions as asthma, COPD and cystic fibrosis. Patients being treated for such conditions may exhibit poor adherence to medication or therapy regimes, practice improper device technique and/or fail to receive feedback about dose assurance. These types of problems may create additional cost burdens for the healthcare system with less than optimal patient outcomes. 
     Medication compliance is often difficult to monitor although this information is invaluable to healthcare and insurance providers. Currently, there is no way to actively monitor a patient&#39;s use of a VHC, and despite the recent advent of smart inhalers, most MDI&#39;s are not able to monitor and communicate medication use on their own. Therefore, the need exists for a VHC that is capable of monitoring medication usage, as well as providing feedback to the user and healthcare and insurance providers. 
     BRIEF SUMMARY 
     Upon insertion of an MDI into a VHC, the system identifies the MDI being inserted in the VHC. As the user performs practice breaths, the system monitors flow rates and provides feedback to the user regarding their technique, including whether the user is breathing too fast, or if their breath-hold is adequate. During this practice phase, the system is capable of notifying the user of the most appropriate time in their breathing cycle to actuate the MDI. 
     Once the MDI is actuated, the system detects and records the actuation, and the duration between actuation and the first inhalation flow. This information is used to provide coordination feedback following the current treatment and/or at the beginning of subsequent treatments. At the end of an inhalation, a second timer may start that measures the breath-hold duration of the user. This information may be used to provide further feedback before the next breath-hold or before the next treatment. 
     Following MDI actuation, the system may determine when the user has received their full dose of medication. This may be accomplished by measuring the flow rate and integrating for total volume delivered or by other means. At the end of treatment, the user is notified and the system, by default, waits for a second actuation of the MDI. If too much time has passed without an actuation, the system will turn off. Additionally, if the user removes the MDI, the program will terminate in one embodiment. 
     Various methods may be used to relay information and provide feedback to the user. LEDs, LED boards, 7-segment displays, LCD and/or OLED screens may be used to provide visual feedback. Audio feedback may also be used with the option of muting the sound at the discretion of the user. Haptic feedback may also be used, with VHC vibrating when an excessive flow rate is pulled, for example. Information may be displayed on a screen, or on a mobile device, remote computer, or other user interface, using, for example, an app or website. 
     The various systems and devices improve patient adherence, improve device technique and provide dose assurance. These aspect, in turn, help reduce costs for healthcare systems and providers (payers) by ensuring proper adherence. In addition, healthcare providers (prescribers), having reliable information about adherence and usage, may then rely on the patient specific data to make informed decisions about treatment protocol and changes. The patients, in turn, receive maximum benefit from the treatment, while also reducing out of pocket costs. 
     The foregoing paragraphs have been provided by way of general introduction, and are not intended to limit the scope of the following claims. The various preferred embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The Figures show different embodiments of medication delivery systems, block/flow diagrams and methods for use and assembly thereof. 
         FIG. 1  is a flow chart illustrating a feedback loop for patient adherence, treatment protocol and payer interaction. 
         FIG. 2  is a flow chart illustrating the use and feedback loops for a smart VHC device. 
         FIG. 3  is a side view of one embodiment of a smart VHC. 
         FIG. 4  is a side view of another embodiment of a smart VHC. 
         FIGS. 5A  and B are actual and greyscale images of a medication container. 
         FIG. 6  is an image showing the proper identification of the medication container shown in  FIG. 5A . 
         FIG. 7  is a side view of various alternative embodiments of a smart VHC. 
         FIG. 8  is a photodetector output v. time graph for an MDI actuation. 
         FIG. 9  is a side view of another embodiment of a smart VHC. 
         FIG. 10  is an output v. flow rate graph for different MDI formulations. 
         FIG. 11  is a schematic for various input/outputs related to MDI use. 
         FIG. 12  is a flow chart illustrating MDI usage and feedback loops. 
         FIG. 13  is a side view of another embodiment of a smart VHC. 
         FIG. 14  is an end view of anther embodiment of a smart VHC. 
         FIG. 15  are graphs showing correlation between the valve opening and flow rate. 
         FIG. 16  is a schematic showing various controller inputs. 
         FIG. 17  is a flow chart illustrating MDI usage and feedback loops. 
         FIG. 18  is a side view of another embodiment of a smart VHC. 
         FIG. 19  is a partial side view of another embodiment of a smart VHC. 
         FIG. 20  is a pressure sensor output v. time for a MDI actuation. 
         FIG. 21  is a pressure change v. time graph during MDI actuation and inhalation. 
         FIG. 22  is a schematic showing various controller inputs. 
         FIG. 23  is a flow chart illustrating MDI usage and feedback loops. 
         FIG. 24  is a side view of another embodiment of a smart VHC. 
         FIG. 25  is a schematic showing MDI recognition via sound. 
         FIG. 26  are graphs showing amplitude v. time at different flow rates. 
         FIG. 27  is a schematic showing various controller inputs. 
         FIG. 28  is a flow chart illustrating MDI usage and feedback loops. 
         FIG. 29  is a side view showing the use of one embodiment of a medication delivery system. 
         FIG. 30  is a perspective view of alternative embodiments of a mask configured with contact sensors. 
         FIG. 31  is a schematic view of a mask, and an enlarged cross-section of a portion of the mask sealing edge. 
         FIG. 32  is a schematic showing the input/output for a controller. 
         FIG. 33  is a flow chart shown illustrating use of a mask. 
         FIG. 34  is a flow chart illustrating use of an active valve. 
         FIG. 35  is a cross-sectional view of one embodiment of an active valve disposed in a flow channel of a medication delivery system. 
         FIG. 36  is an end view of one embodiment of the valve shown in  FIG. 35 . 
         FIG. 37  is a flow v. time graph showing an inhalation and exhalation cycle with and without an active valve. 
         FIG. 38  is a side view of an alternative embodiment of a smart VHC. 
         FIG. 39  are minimum plume temperature as a function of distance from thermocouple for various MDI products. 
         FIG. 40  is a partial, cross-sectional side view of an MDI applied to one embodiment of a VHC. 
         FIG. 41  is a partial, cross-sectional side view of an MDI applied to another embodiment of a VHC. 
         FIG. 42  is a force v. displacement for an exemplary MDI actuation. 
         FIG. 43  is an end view of one embodiment of a backpiece of a VHC. 
         FIG. 44  is a side view of the backpiece shown in  FIG. 43 . 
         FIGS. 45A  and B are partial, cross-sectional side views of an MDI in an actuated and non-actuated positions relative to a smart VHC. 
         FIG. 46  is a partial, cross-sectional view of one embodiment of a smart MDI. 
         FIG. 47  is a partial, cross-sectional view of one embodiment of a smart MDI. 
         FIG. 48  is a partial, cross-sectional view of one embodiment of a smart MDI. 
         FIG. 49  is a side view of one embodiment of a smart MDI. 
         FIG. 50  is an enlarged partial view of the smart MDI shown in  FIG. 49 . 
         FIGS. 51A-C  are various side views of alternative VHC embodiments. 
         FIG. 52  is a partial, cross-sectional side view of one embodiment of a VHC. 
         FIG. 53  is a partial, cross-sectional side view of one embodiment of a VHC. 
         FIG. 54  is a partial, cross-sectional side view of one embodiment of a VHC. 
         FIG. 55  is a pressure v. flow graph of various MDI devices. 
         FIG. 56  is a side view of one embodiment of a VHC. 
         FIG. 57  is an enlarged partial side view of the VHC shown in  FIG. 56 . 
         FIG. 58  is a side view of one embodiment of a VHC. 
         FIGS. 59A-C  are various views of a duckbill valve with a vibrating beam. 
         FIG. 60  is a partial, cross-sectional side view of one embodiment of a flow rate sensor assembly. 
         FIG. 61  is a partial, cross-sectional side view of one embodiment of a flow rate sensor assembly. 
         FIG. 62  is a partial, cross-sectional side view of one embodiment of a flow rate sensor assembly. 
         FIG. 63  is a side view of one embodiment of a VHC. 
         FIG. 64  is a side view of another embodiment of a VHC. 
         FIG. 65  is a side view of another embodiment of a VHC. 
         FIGS. 66A-C  are various graphical displays with user indicia. 
         FIG. 67  is a pictorial showing communication between a smart VHC and user interface. 
         FIG. 68  is a partial, cross-sectional side view of a MDI inserted into a VHC. 
         FIG. 69  is a partial, cross-sectional side view of and VHC in a partially and fully inserted position. 
         FIG. 70  is an end view of one embodiment of a VHC. 
         FIG. 71  is an end view of another embodiment of a VHC. 
         FIG. 72  is an end view of another embodiment of a VHC. 
         FIG. 73  is an end view of another embodiment of a VHC. 
         FIG. 74  is an end view of another embodiment of a VHC. 
         FIG. 75  shows an MDI configured with a conductive material for closing a circuit path in a VHC. 
         FIG. 76  is a side view of an MDI and VHC. 
         FIG. 77  is a view of a display for an MDI or VHC. 
         FIG. 78  is a side view of one embodiment of a smart VHC. 
         FIG. 79  is a perspective view of a valve holding chamber with an adapter having a display. 
         FIG. 80  is a perspective view of the adapter shown in  FIG. 79 . 
         FIG. 81  is a perspective view of a valve holding chamber with a backpiece having a display. 
         FIG. 82  is a perspective view of the backpiece shown in  FIG. 81 . 
         FIG. 83  is a schematic illustrating the computer structure. 
         FIG. 84  is a schematic illustration of a communication system. 
         FIG. 85  is a flow chart showing usage protocol of a smart VHC and MDI. 
         FIG. 86  is a view of a smart VHC and MDI. 
         FIG. 87  is a side view of one embodiment of an active valve. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS AND THE PRESENTLY PREFERRED EMBODIMENTS 
     It should be understood that the term “plurality,” as used herein, means two or more. The term “coupled” means connected to or engaged with whether directly or indirectly, for example with an intervening member, and does not require the engagement to be fixed or permanent, although it may be fixed or permanent (or integral), and includes both mechanical and electrical connection. The terms “first,” “second,” and so on, as used herein are not meant to be assigned to a particular component so designated, but rather are simply referring to such components in the numerical order as addressed, meaning that a component designated as “first” may later be a “second” such component, depending on the order in which it is referred. It should also be understood that designation of “first” and “second” does not necessarily mean that the two components or values so designated are different, meaning for example a first component may be the same as a second component, with each simply being applicable to separate but identical components. 
     In a traditional patient/prescriber/payer model, the patient is prescribed a therapy and purchases the medications and/or therapy device. If the purchase is covered by a payer, there typically is no feedback to the payer that the therapy is being performed correctly and as prescribed, aside from future requests for additional therapies. The patient typically is trained on the use of the medical device by a prescriber and then asked to use the device in their daily life. At some point, the patient may follow up with the prescriber because of a condition change, a prescription refill, or perhaps at a set frequency. At such a time, the prescriber may evaluate the effectiveness of the treatment and decide to modify or continue therapy. If the prescriber decides to modify the therapy, then a new prescription is given and the cycle repeated. Some of the technical challenges faced in improving adherence to treatment regimens, that in turn may lead to improved cost tracking and diagnosis, include challenges in the ability to effectively monitor the functions of different therapeutic devices and the usage of the device, how to then provide an effective real-time feedback to a user and/or a prescriber, and how to make real-time changes to the performance of the device and/or behavior/technique of the user in certain instances. 
     Referring to  FIGS. 1 and 2 , various smart devices, and feedback associated therewith, may be introduced to improve the effectiveness of the therapy. In addition, the prescriber is provided patient-specific data to make informed decisions about treatment, including the modification thereof, and the payer is provided with an assurance that the patient has adhered to the treatment regimen before covering the costs of another prescription. 
     Referring to  FIG. 3 , one exemplary embodiment of a smart VHC includes a chamber housing  2  having a wall defining an interior space  4  extending along a longitudinal axis/inhalation flow path  6 , a back piece  8  coupled to an input end  10  of the chamber housing and a mouthpiece and/or valve assembly  12  coupled to an output end  14  of the chamber housing. The mouthpiece assembly may be releasably and removably coupled to the chamber housing, for example with tabs received in grooves. The mouthpiece is configured with an inhalation valve  16  and/or an exhalation valve  18 , which provides an exhalation flow path  13 . The inhalation and exhalation valves may alternatively be disposed on other components of the VHC. In various embodiments, a valve is configured as part of an annular donut valve, having an inner periphery that defines the inhalation valve  16  and an outer periphery defining an exhalation valve  18 . In other embodiments, the inhalation valve is configured as a duckbill valve, which may also have an outer annular flange defining the exhalation valve. In other embodiments, the inhalation and exhalation valves may not be integral, but rather are separately formed and disposed within the VHC. The backpiece  8  is configured with an opening  20 , which is shaped to receive a mouthpiece portion  22  of a MDI actuation boot  24 . The boot further includes a chimney portion  26  defining a cavity shaped to receive a medicament container  28 . The boot further includes a support block defining a well shaped to receive a valve stem of the MDI. The well communicates with an orifice, which releases aerosolized medication into the interior space of the chamber housing. Various embodiments of the VHC and MDI, including the mouthpiece assembly, chamber housing and backpiece, are disclosed for example and without limitation in U.S. Pat. Nos. 6,557,549, 7,201,165, 7,360,537 and 8,550,067, all assigned to Trudell Medical International, the Assignee of the present application, with the entire disclosures of the noted patents being hereby incorporated herein by reference. 
     In one embodiment, the VHC  3  is configured to correctly identify the MDI being inserted into the VHC, correctly identify when the MDI  5  has been actuated, and monitor and provide feedback to the user regarding proper technique, as shown for example in  FIG. 12 . For example, and referring to  FIGS. 3 and 7 , the VHC may have a Blue LED  30  coupled to the wall of the chamber housing in the interior space  4  and a photodetector  32  also disposed in the interior space  4  at a spaced apart location from the LED  30 . The photodetector  32  may be coupled, for example to the wall. A camera  35  may be coupled to the holding chamber  2 , for example adjacent the mouthpiece assembly  12 , or closer to the backpiece  8 . A flow detector, such as a flow sensor  34 , is coupled to the wall of the chamber housing, and has an input port  36  and an output port  38  communicating with the interior space. A feedback device, such as a visual feedback indicator  40 , for example an LED, or array of LED&#39;s, is disposed on the backpiece  8 , although it may also be coupled to the chamber housing or mouthpiece assembly. 
     As shown in  FIGS. 79 and 80 , an adapter  50  includes a shell having a C-shape interior  52  shaped to engage, e.g., with a snap-fit, the chamber housing  2 . The adapter includes a feedback device, configured as a display  54  visible to the user, and may include a microcontroller  56  and communication components. As shown in  FIGS. 81 and 82 , the backpiece includes a display  54  and/or microcontroller  56 . The display  54  in each embodiment displays various information, such as various feedback information disclosed herein, to the user and/or caregiver. In different embodiments, the microcontroller  56  may implemented as the controller arrangement illustrated in  FIG. 16 , microcontroller arrangements of  FIG. 22 or 27 , or as a processor  502  with one or more components of a more complete computer  500  as shown in  FIG. 83 . 
     Communication and Data Processing 
     In seeking to satisfy these propositions, the device, such as a VHC associated with an MDI, may be configured to perform one or more of the following: (1) correctly identify the MDI being used with the VHC, (2) correctly identify when the MDI has been actuated, (3) monitor and provide feedback to the user regarding proper technique and (4) provide patient specific data to the prescriber and/or provider. Referring to  FIGS. 2, 16, 65, 66A -C,  67 ,  83  and  84 , one aspect of the embodiments relates to the handling of data. Data logged by the VHC and/or MDI may be transferred to an external device, such as a smartphone, tablet, personal computer, etc. If such an external device is unavailable, the data may be stored internally in the VHC and/or MDI in a data storage module or other memory and transferred upon the next syncing between the VHC/MDI and external device. Software may accompany the VHC/MDI to implement the data transfer and analysis. 
     In order to provide faster and more accurate processing of the data, for example from one or more various sensors, generated within the smart VHC and/or MDI, data may be wirelessly communicated to a smart phone, local computing device and/or remote computing device to interpret and act on the raw sensor data. 
     In one implementation, the smart VHC and/or MDI includes circuitry for transmitting raw sensor data in real-time to a local device, such as a smart phone. The smart phone may display graphics or instructions to the user and implement processing software to interpret and act on the raw data. The smart phone may include software that filters and processes the raw sensor data and outputs the relevant status information contained in the raw sensor data to a display on the smart phone. The smart phone or other local computing device may alternatively use its local resources to contact a remote database or server to retrieve processing instructions or to forward the raw sensor data for remote processing and interpretation, and to receive the processed and interpreted sensor data back from the remote server for display to the user or a caregiver that is with the user of the smart VHC. 
     In addition to simply presenting data, statistics or instructions on a display of the smart phone or other local computer in proximity of the smart VHC and/or MDI, proactive operations relating to the smart VHC and/or MDI may be actively managed and controlled. For example, if the smart phone or other local computer in proximity to the smart VHC and/or MDI determines that the sensor data indicates the end of treatment has been reached, or that further treatment is needed, the smart phone or other local computing device may communicate such information directly to the patient. Other variations are also contemplated, for example where a remote server in communication with the smart phone, or in direct communication with the smart VHC and/or MDI via a communication network, can supply the information and instructions to the patient/user. 
     In yet other implementations, real-time data gathered in the smart VHC and/or MDI and relayed via to the smart phone to the remote server may trigger the remote server to track down and notify a physician or supervising caregiver regarding a problem with the particular treatment session or a pattern that has developed over time based on past treatment sessions for the particular user. Based on data from the one or more sensors in the smart VHC and/or MDI, the remote server may generate alerts to send via text, email or other electronic communication medium to the user, the user&#39;s physician or other caregiver. 
     The electronic circuitry in the smart VHC and/or MDI (e.g. the controller arrangement of  FIG. 16 ), the local computing device and/or the remote server discussed above, may include some or all of the capabilities of a computer  500  in communication with a network  526  and/or directly with other computers. As illustrated in  FIGS. 65, 6A -C,  67 ,  76 ,  77 ,  83  and  84 , the computer  500  may include a processor  502 , a storage device  516 , a display or other output device  510 , an input device  512 , and a network interface device  520 , all connected via a bus  508 . A battery  503  is coupled to and powers the computer. The computer may communicate with the network. The processor  502  represents a central processing unit of any type of architecture, such as a CISC (Complex Instruction Set Computing), RISC (Reduced Instruction Set Computing), VLIW (Very Long Instruction Word), or a hybrid architecture, although any appropriate processor may be used. The processor  502  executes instructions and includes that portion of the computer  500  that controls the operation of the entire computer. Although not depicted in  FIGS. 83 and 84 , the processor  502  typically includes a control unit that organizes data and program storage in memory and transfers data and other information between the various parts of the computer  500 . The processor  502  receives input data from the input device  512  and the network  526  reads and stores instructions (for example processor executable code)  524  and data in the main memory  504 , such as random access memory (RAM), static memory  506 , such as read only memory (ROM), and the storage device  516 . The processor  502  may present data to a user via the output device  510 . 
     Although the computer  500  is shown to contain only a single processor  502  and a single bus  508 , the disclosed embodiment applies equally to computers that may have multiple processors and to computers that may have multiple busses with some or all performing different functions in different ways. 
     The storage device  516  represents one or more mechanisms for storing data. For example, the storage device  516  may include a computer readable medium  522  such as read-only memory (ROM), RAM, non-volatile storage media, optical storage media, flash memory devices, and/or other machine-readable media. In other embodiments, any appropriate type of storage device may be used. Although only one storage device  516  is shown, multiple storage devices and multiple types of storage devices may be present. Further, although the computer  500  is drawn to contain the storage device  516 , it may be distributed across other computers, for example on a server. 
     The storage device  516  may include a controller (not shown) and a computer readable medium  522  having instructions  524  capable of being executed on the processor  502  to carry out the functions described above with reference to processing sensor data, displaying the sensor data or instructions based on the sensor data, controlling aspects of the smart VHC and/or MDI to alter its operation, or contacting third parties or other remotely located resources to provide update information to, or retrieve data from those remotely located resources. In another embodiment, some or all of the functions are carried out via hardware in lieu of a processor-based system. In one embodiment, the controller is a web browser, but in other embodiments the controller may be a database system, a file system, an electronic mail system, a media manager, an image manager, or may include any other functions capable of accessing data items. The storage device  516  may also contain additional software and data (not shown), which is not necessary to understand the invention. 
     The output device  510  is that part of the computer  500  that displays output to the user. The output device  510  may be a liquid crystal display (LCD) well-known in the art of computer hardware. In other embodiments, the output device  510  may be replaced with a gas or plasma-based flat-panel display or a traditional cathode-ray tube (CRT) display. In still other embodiments, any appropriate display device may be used. Although only one output device  510  is shown, in other embodiments any number of output devices of different types, or of the same type, may be present. In an embodiment, the output device  510  displays a user interface. The input device  512  may be a keyboard, mouse or other pointing device, trackball, touchpad, touch screen, keypad, microphone, voice recognition device, or any other appropriate mechanism for the user to input data to the computer  500  and manipulate the user interface previously discussed. Although only one input device  512  is shown, in another embodiment any number and type of input devices may be present. 
     The network interface device  520  provides connectivity from the computer  500  to the network  526  through any suitable communications protocol. The network interface device  520  sends and receives data items from the network  526  via a wireless or wired transceiver  514 . The transceiver  514  may be a cellular frequency, radio frequency (RF), infrared (IR) or any of a number of known wireless or wired transmission systems capable of communicating with a network  526  or other smart devices  102  having some or all of the features of the example computer of  FIGS. 83 and 84 . The bus  508  may represent one or more busses, e.g., USB, PCI, ISA (Industry Standard Architecture), X-Bus, EISA (Extended Industry Standard Architecture), or any other appropriate bus and/or bridge (also called a bus controller). 
     The computer  500  may be implemented using any suitable hardware and/or software, such as a personal computer or other electronic computing device. The computer  500  may be a portable computer, laptop, tablet or notebook computers, smart phones, PDAs, pocket computers, appliances, telephones, and mainframe computers are examples of other possible configurations of the computer  500 . The network  526  may be any suitable network and may support any appropriate protocol suitable for communication to the computer  500 . In an embodiment, the network  526  may support wireless communications. In another embodiment, the network  526  may support hard-wired communications, such as a telephone line or cable. In another embodiment, the network  526  may support the Ethernet IEEE (Institute of Electrical and Electronics Engineers) 802.3x specification. In another embodiment, the network  526  may be the Internet and may support IP (Internet Protocol). In another embodiment, the network  526  may be a LAN or a WAN. In another embodiment, the network  526  may be a hotspot service provider network. In another embodiment, the network  526  may be an intranet. In another embodiment, the network  526  may be a GPRS (General Packet Radio Service) network. In another embodiment, the network  526  may be any appropriate cellular data network or cell-based radio network technology. In another embodiment, the network  526  may be an IEEE 802.11 wireless network. In still another embodiment, the network  526  may be any suitable network or combination of networks. Although one network  526  is shown, in other embodiments any number of networks (of the same or different types) may be present. 
     It should be understood that the various techniques described herein may be implemented in connection with hardware or software or, where appropriate, with a combination of both. Thus, the methods and apparatus of the presently disclosed subject matter, or certain aspects or portions thereof, may take the form of program code (i.e., instructions) embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, or any other machine-readable storage medium wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the presently disclosed subject matter. In the case of program code execution on programmable computers, the computing device generally includes a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device. One or more programs may implement or use the processes described in connection with the presently disclosed subject matter, e.g., through the use of an API, reusable controls, or the like. Such programs may be implemented in a high level procedural or object-oriented programming language to communicate with a computer system. However, the program(s) can be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language and it may be combined with hardware implementations. Although exemplary embodiments may refer to using aspects of the presently disclosed subject matter in the context of one or more stand-alone computer systems, the subject matter is not so limited, but rather may be implemented in connection with any computing environment, such as a network or distributed computing environment. Still further, aspects of the presently disclosed subject matter may be implemented in or across a plurality of processing chips or devices, and storage may similarly be spread across a plurality of devices. Such devices might include personal computers, network servers, and handheld devices, for example. 
     Proper Technique 
     Providing feedback to users regarding their inhalation technique is one feature of the VHC that will help optimize drug delivery. In one embodiment, shown in  FIGS. 3 and 9 , a flow detector, configured as a flow sensor  34 , is used to collect data and provide feedback about technique. The flow sensor measures the flow rate at which the user is inhaling. Inhaling too fast may deposit most of the drug in the throat rather than in the lungs. Effective drug deposition into the lungs may be achieved with controlled inhalation. In addition, the flow rate may be integrated over time to determine the volume of air inhaled, which may be used to provide the user with an indication of when they have emptied the interior space of the chamber housing and received a complete dose. As shown in  FIGS. 3 and 9 , the flow sensor  34  includes a  58  bypass channel with input and output ports  36 ,  38  communicating with the interior space. The pressure differential between the proximal and distal openings defined by the input and output ports creates a small flow rate through the bypass channel. A thermal mass air flow sensor  60  is used to measure the flow through the bypass channel, which is correlated to inhalation flow rates, as shown in  FIG. 9 . The flow sensor  34 ,  34 ′ may be placed at either location shown in  FIG. 9 . The flow sensor measures the flow without being disposed in, or interfering with, the flow path in the interior space  4 . As such, the flow sensor does not interfere with the aerosol medication or flow path through the interior space. The flow rate information may be combined with the MDI actuation detection and MDI identification, described in more detail below, to provide reliable insight to patient behavior and use of the device. 
     Referring to  FIG. 12 , the flow rate information may be used in real-time to provide feedback to the user about practice sessions, for example through a feedback device such as an indicator (visual, auditory and/or haptic) or display, and whether they should begin inhalation, and/or whether they need to slow down the flow rate, for example when exceeding a maximum flow rate. MDI actuation may also be used to provide feedback to the user about initiating actuation and/or beginning inhalation. First, the user  66  inserts the MDI into the backpiece as shown in  FIG. 19 . A contact switch  62 , or other MDI insertion detector or sensor, detects the insertion. When the MDI is inserted, the smart VHC actively looks for MDI actuation and/or inhalation flow detection. Depending on the feedback through a feedback device (e.g., indicator or display), the user may actuate the MDI, dispensing an aerosolized medication into the interior space, with an actuation time stamp being recorded. The processor  502  then looks for inhalation flow, as communicated by the flow sensor  34 , and records flow rate and a timestamp of active inhalation. The processor  502  also compares the inhalation rate with a stored predetermined rate, e.g., a maximum recommended flow rate, and provides feedback to the user if the inhaled flow rate exceeds the predetermined flow rate. The processor then compares the inhaled volume, as calculated from the flow rate, with the volume of the interior space  4 , and notifies the user that the treatment is complete and the dose has been properly administered. Alternatively, the processor may communicate to the user that further inhalation is required to fully empty the interior space. As noted, the user has the option to practice using the device before the treatment begins. In this case, the MDI is not inserted. Rather, only the flow sensor is activated. The processor records the flow rate and provides feedback about the flow rate, and notifies the user that the practice is complete. 
     Referring to  FIGS. 14-17 , one embodiment of a smart VHC includes a thin skin-like patch including a resistive strain gauge  68  mounted on the inhalation valve  16  to measure the valve opening  70  geometry during inhalation. The strain gauge may be applied to the valve with adhesive or by insert molding during injection holding of the valve. As shown in  FIG. 15 , the size and duration of the opening of the valve  16  may be correlated with the inhalation flow rate to confirm completion of inhalation. 
     As shown in  FIG. 16 , a controller, which may be located on or inside the various embodiments of the smart VHC described herein, is in communication with one or more sensors, switches and or gauges that are tracking or controlling operation of the smart VHC. The controller may store data gathered in a memory for later download to a receiving device, or may transmit data to a receiving device in real-time. Additionally, the controller may perform some processing of the gathered data from the sensors, or it may store and transmit raw data. RF transmitter and/or receiver modules may be associated with the controller on the smart VHC to communicate with remote hand-held or fixed computing devices in real-time or at a later time when the smart VHC is in communication range of a communication network to the remote hand-held or fixed location computing devices. The controller may include one or more of the features of the computer system  500  shown in  FIG. 83 . Additionally, the one or more sensors, switches or gauges may be in wired or wireless communication with the controller. 
     For clarity in displaying other features of the various Smart VHC embodiments described, the controller circuitry is omitted, however a controller or other processing agent capable of at least managing the routing or storing of data from the smart VHC is contemplated in one version of these embodiments. In other implementations, the smart VHC may not include an onboard processor and the various sensors, gauges and switches of a particular embodiment may wirelessly communicate directly with a remotely located controller or other processing device, such as a handheld device or remote server. Data gathered by a controller or other processing device may be compared to expected or pre-programmed values in the local controller memory or other remote location to provide the basis for feedback on whether desired performance or therapy is taking place. If the controller is a more sophisticated and includes more of the computer  500  elements described in  FIG. 83 , then this processing may all be local to the smart device (smart VHC, smart MDI, etc.). In more rudimentary controller arrangements, the data may simply be date/time stamped and stored locally or remotely for later processing. In one embodiment, the data may further be locally or remotely stamped with a unique device or patient identifier. 
     Breath-hold may also be one particular step to facilitate diffusion of the drug and optimize deposition within the lungs. The user&#39;s breath-hold may be monitored using methods below or the user may simply be encouraged to hold their breath visually or audibly without monitoring breath-hold directly. 
     1. Carbon Dioxide Detection 
     1.1. Referring to  FIG. 86 , carbon dioxide is a byproduct of cellular respiration which is expelled from the body through exhaled breath. As a result, the concentration of carbon dioxide in exhaled breath is significantly higher than the concentration of ambient air. Using a carbon dioxide sensor  76 , the carbon dioxide concentration within the mouthpiece and mask adapter portions of the VHC may be monitored with higher concentrations indicating the expiratory phase of the user&#39;s breathing cycle. Combining this data with inspiratory flow data or other means of detecting the user&#39;s inhalation, breath-hold duration can be determined and used to provide feedback to the user. The end of inhalation may be determined, for example, using a flow or pressure threshold. Once the inspiratory flow or pressure falls below this threshold, the breath-hold timer can start and it will not stop until a spike in carbon dioxide concentration is detected. 
     2. Pressure Monitoring 
     2.1. Referring to  FIGS. 18-20 , a pressure sensor  78  may be positioned within the mouthpiece/mask adapter or chamber housing, such that inhalation and exhalation phases of the user&#39;s breathing cycle may be monitored. Inspiratory and expiratory pressure thresholds may be used in order to calculate the duration of the user&#39;s breath-hold. When the inspiratory pressure falls below the inspiratory threshold, the breath-hold timer begins and once exhalation begins and the expiratory pressure threshold is exceeded, the breath hold timer stops. The pressure sensor  78  communicates with the computer  500  and processor  502 . 
     In addition, the device provides information about when the chamber is empty by assuming a tidal volume and counting the number of inhalation breaths. The assumed tidal volume may be based on age and sex, and may be selected during setup. Since the volume of the interior space  4  is known, the computer/processor  500 ,  502  processes positive pressure events to identify when the MDI has been actuated, then counts the number of negative pressure events, which indicate inhalation, until the chamber volume has been reached. Each negative pressure event should be spaced apart a normal breathing cycle, e.g., 2-5 seconds, with the chamber volume being evacuated within a finite total treatment time period. If this is satisfied, a determination is made that the drug was fully delivered. Otherwise, feedback may be provided to the user to continue inhalation and/or the breathing cycle. Feedback may be audible, visual or tactile/haptic (e.g., vibratory), or any combination thereof using the various indicators described herein elsewhere. The information may be logged and stored, and/or feedback provided that additional training is needed. 
     3. Microphone 
     3.1. Inhaled and exhaled air travel different paths through the VHC during use. Since different flow paths are used, it is possible that flow through these paths will sound different from one another. A microphone  82 , as shown for example in  FIG. 24 , may be used to listen for inhalation and exhalation and may be used to calculate breath-hold durations using a threshold method similar to embodiments 1.1 and 2.1. 
     In addition, during treatment, and once the MDI has been actuated, the microphone(s) record the sound of air flow through the VHC and, based on the amount of turbulence recorded by the microphone, may be monitored and analyzed by the microprocessor. For example, the amplitude of the translated sound over a period of time correlates to a specific flow rate, or range of flow rates, as shown in  FIG. 26 . The VHC may provide feedback, by way of an indicator (visual, auditory, tactile, etc.) to the user that the inhalation rate is excessive, or exceeding a predetermined maximum flow rate. Other feedback may include information that the treatment is complete or that a data upload is complete. Upon completion of treatment, the system is reset and ready for another MDI actuation. 
     Referring to  FIG. 58 , a reed, or an array or series of reeds  84 , e.g., plastic or silicone, may be disposed adjacent the microphone  82 . Differential flow activates or creates different acoustical outputs from the reed(s), which may be picked up and recorded by the microphone  82 . As shown in  FIGS. 59A-C , a single reed  115 , or beam, may be disposed across the mouth of a valve, shown as a duckbill valve. As the flaps  88  of the valve are opened or closed different amounts, e.g., in response to the flow rate, the reed  115 , which acts as a vibrating string, is made thinner or thicker, such that it produces different acoustical signals that may be picked up by the microphone  82 . The microphone communicates with the computer  500  and processor  502 . 
     4. Humidity Sensor 
     4.1. Air from the ambient environment becomes saturated with water vapor when it enters the lungs. When this air is exhaled, it passes through the mouthpiece and mask adapter where the humidity of the air can be analyzed. By continuously monitoring humidity levels with a sensor  90  as shown in  FIG. 86 , in the mouthpiece and mask adapter, the exhalation phase of the breathing cycle may be detected and used to determine breath-hold duration in a similar manner as embodiments 1.1 and 2.1. The humidity sensor  90  communicates with the computer  500  and processor  502 . 
     5. Temperature Sensors 
     5.1. As ambient air enters the body, it is warmed to body temperature. Using a temperature sensor  92  (see, e.g.,  FIG. 86 ), air temperature may be monitored in the mouthpiece and mask adapter. When an abrupt rise in temperature is seen, it may be interpreted as an exhalation from the user. Similar to previous breath-hold detection embodiments, combining this detection of the beginning of exhalation with inspiratory measurements (i.e. flow or pressure), breath-hold duration may be calculated and fed back to the user for technique improvement. The temperature sensor  92  communicates with the computer  500  and processor  502 . 
     6. Light Curtain 
     6.1. Referring to  FIGS. 63 and 86 , a light curtain  94  or plurality of light curtains may be used in conjunction with a flexible member  96  which responds to negative and positive pressures. During inhalation, the flexible member may be drawn in a direction such that one of the pair of light curtains has its light beam broken (or restored) and this may be interpreted as an inhalation by the user. In contrast, the flexible member may be forced in an opposite direction during exhalation where the second of the light curtains has its beam broken (or restored). This is interpreted as the user&#39;s exhalation. Using these measurements, the time in which both light curtains are unbroken indicates the breath-hold duration. Alternatively, a single light curtain may be used to detect exhalation by the user and another method (e.g. inspiratory pressure or flow threshold) may be used to determine the end of inhalation. 
     6.2. In another embodiment, the moisture in the user&#39;s exhaled breath may be sufficient to break the light curtain responsible for detecting exhalation in which case, no flexible member is needed. 
     End of Treatment 
     When receiving aerosol from a valved holding chamber, particularly for mask products in the infant and baby populations, one uncertainty is knowing at what point the user has received all of the medication from the chamber. Premature chamber removal may lead to under-dosing as will excess mask leakage during aerosol administration. By monitoring the aerosol within the chamber or the volume of air inhaled through the chamber, feedback may be given to the user regarding end of treatment. This provides dose assurance to all parties involved in the patient&#39;s health. 
     1. Capacitance Change 
     1.1. Assuming the aerosol has a different dielectric compared to that of air, a change in capacitance of the capacitor  106  shown in  FIGS. 43 and 44  may be used to detect when all aerosol has vacated the chamber. A baseline capacitance would be measured prior to aerosol actuation and treatment would not end until the capacitance returned to this baseline value or some similar value. 
     2. Light Transmission/Reflection 
     2.1. As shown in  FIGS. 3 and 7 , a light source  30  and photodetector  32  may be set up in any orientation relative to the flow with the light source aimed directly at the photodetector or reflected off of a surface towards the photodetector. When aerosol is present, this light is scattered, diffused, refracted, absorbed and reflected so that the amount of light returning to the photodetector is reduced. End of treatment occurs when the baseline readings are approached. 
     Flow Detection 
     Aerosol deposition in the throat and upper airway may occur when flow rates get too high leading to side effects as well as depriving the lung of medication. The smart VHC should have a feedback device or feature informing the user if the predetermined, maximum recommended flow rate has been exceeded, using a flow detector, and allowing the user to slow their inhalation to an effective rate. All embodiments of the flow detectors, alone or in combination, as described below may be used for this purpose, in addition to helping determine end of treatment. End of treatment is determined by integrating these flow rates overtime until a threshold volume has been reached, as shown in  FIG. 12 . The threshold volume is chosen such that all aerosol is inhaled from the chamber. 
     3. Pressure Sensors 
     3.1. Differential Pressure Across A Valve 
     A valve is chosen such that its resistance is consistent, has low hysteresis and is preferably linear, as shown in  FIG. 46 . The flow through the valve can then be inferred based on the differential pressure reading across the valve. 
     3.2. Differential Pressure Across MDI 
     3.2.1. MDI Boot 
     An MDI identifier is used to identify the MDI being used with the chamber. Assuming this information is known, the MDI&#39;s resistance profile (pressure vs. flow curve) can be accessed from a predefined database and using a differential pressure measurement comparing the pressure at the mouthpiece of the MDI as detected by a pressure sensor  78  to atmospheric pressure, as shown in  FIG. 47 , the flow through the MDI itself can be calculated. 
     3.2.2. Molded MDI Adapter Boot (Canister Inserted) 
     Since most MDI will have different resistance profiles from one another, the canister may be removed from the boot and placed into a built in receptacle molded into the MDI adapter, or backpiece. This adapter would allow all MDI canisters to be inserted and for aerosol to enter the chamber. The resistance to flow of the MDI adapter can then be designed specifically to the system&#39;s needs, that is, linear PO curve, low hysteresis and consistent from part to part. 
     3.3. Differential Across an Orifice in a Bypass 
     3.3.1. As shown in  FIGS. 3, 9, 49 and 50 , a bypass channel  60  exists on the inside of the chamber wall or mouthpiece/mask adapter and this channel is in fluid communication with the aerosol chamber. During inhalation, some flow is drawn through this bypass channel and through an orifice  110  of precisely controlled size. The resistance to flow of this orifice can be thoroughly characterized and measurements of differential pressure using a pressure sensor  78  across the orifice  110  may be used to calculate flow though the orifice and bypass channel. Flow rates through the chamber will be calibrated to the flow through the bypass channel such that bypass flow measurements during use can indicate total flow through the VHC. The pressure sensor  78  communicates with the computer  500  and processor  502 . 
     3.4. Venturi 
     3.4.1. A venturi  112  uses a local constriction of the flow path to accelerate the fluid as it passes through. As the fluid velocity increases, its pressure decreases relative to that of the slower moving fluid upstream of the constriction. A differential pressure sensor can detect this difference and with knowledge of the venturi geometry, flow rate can be calculated. 
     The venturi  112  can be molded as part of the chamber housing  2 , as a part of the mouthpiece  12  or as part of a bypass flow path  60  as shown in  FIGS. 51A-C  respectively. The pressure sensor  78  communicates with the computer  500  and processor  502 . 
     3.5. Pitot Static Tube 
     3.5.1. Pitot static tubes  114  consist of a tube with one closed end and means of comparing the pressure within the tube to the surrounding fluid pressure. As the fast moving air enters the Pitot tube  114 , it stagnates and builds a pressure within the tube that is proportional to the initial speed of the fluid flow. 
     A pitot tube may be molded in or assembled onto a baffle  116  of the valved holding chamber so as to sample the fastest moving air during inhalation as shown in  FIG. 52 . This velocity can be turned into a flow rate estimation with knowledge of the chamber geometry. A pressure sensor  78  detects the pressure differential and communicates with the computer  500  and processor  502 . 
     4. Sound-Based Methods 
     For all sound-based methods, a second microphone may be used to detect ambient noise. This information can then be used for noise reduction in the signal being processed by the microcontroller or other processor  502 . 
     4.1. Volume Based 
     4.1.1. Intrinsic Sounds 
     As air rushes through the MDI and valved holding chamber, turbulence is generated which produces sound. At higher flow rates, more turbulence is generated and louder sounds are present. Monitoring the volume of sound within the chamber can provide a means of estimating flow rate although non-filtered volume-based methods would be highly vulnerable to environmental noise. 
     A microphone  82  is placed in the interior space of the chamber housing, for example as coupled to an adapter or the backpiece (see, e.g.,  FIG. 24 ), or along the chamber or at the baffle (see e.g.,  FIG. 59C ). This same microphone may be used for MDI actuation detection. 
     4.1.2. Sound Generation 
     A microphone is placed in a similar spot as in embodiment 4.1.1. As shown in  FIGS. 58 and 59A -B, a vibrating reed  115  or reeds  84 , edge tones or flow over an open or closed tube may be used to generate sound as flow passes over and this volume should be substantially larger than those present in the chamber itself. The microphone  82  communicates with the computer  500  and processor  502 . 
     4.2. Low Pass, High Pass and Band Pass Filter Volume Based 
     As mentioned in embodiment 4.1.1., volume based methods may be vulnerable to false readings due to ambient noise. To reduce this risk, digital and/or analog filtering may be implemented so that the system is only effectively “listening” to particular frequency bands. These filters would be selected such that the sounds intrinsic to the chamber are listened to or in the case of the sound generation, these frequencies are monitored. 
     4.3. Algorithm Based 
     The sounds coming from the chamber at different flow rates, whether these sounds are intrinsic to the product or produced by means of a reed or other sound generating source, will be fairly unique to the system. Various algorithms may be used to quantitatively compare the incoming microphone signal to a range of signals that have been pre-recorded at defined flow rates from within the device. 
     4.4. Acoustic Time Of Flight (TOF) 
     Referring to  FIG. 64 , acoustic TOF, in this case, refers to the time it takes for sound to travel from one sound transceiver  118  to another. Transceiver one (T 1 ) is located downstream of transceiver two (T 2 ) which may both be situated inside or outside of the chamber. As sound travels from T 1  to T 2 , it is effectively slowed down as a result of travelling against the air flow through the chamber. Conversely, as sounds travels from  12  to Ii, it does so faster than normal as it is moving with the flow. Knowing the angle θ of the transceivers  118 , or ultrasonic transducers, relative to the direction of flow as well as the TOF from  11  to  12  and  12  to T 1 , the average flow velocity and therefore flow rate can be estimated with knowledge of the chamber geometry. Sound of any frequency can work although it would be desirable to be outside of the human audible range (&gt;20 kHz). The transceivers  118  communicate with the computer  500  and processor  502 . 
     4.5. Doppler 
     Doppler ultrasound uses the shift in frequency of a reflected wave relative to the transmitted wave to infer the speed at which the reflecting body is moving. Using the suspended aerosol particles as reflecting bodies, the Doppler principle may be used to determine average particle velocity and estimate flow rate. This method would only detect flow when aerosol is present so it may also be used as a further dose assurance tool. 
     As shown in  FIG. 53 , an ultrasonic transducer  118  may be placed in the baffle  116  with sound directed towards the MDI adapter or backpiece  8 , in the MDI adapter with sound directed towards the baffle or anywhere in between as long as the sound production is not perpendicular to the direction of airflow. The transceiver/transducer  118  communicates with the computer  500  and processor  502 . 
     5. Light-Based Methods 
     5.1. Internal Reflection in a Valve with a Slit 
     Referring to  FIG. 60 , a light-emitting diode (LED)  122  or other light source and/or a photodetector  124  sensitive to the wavelength of light coming from the LED are positioned within a valve  16  with both directed towards the valve opening  126 . The valve is of the type with a variable sized opening whose opening size is dependent on the flow rate passing through the valve. Duckbill, cross valves and any die cut valves are good examples however this list is not exclusive. Referring to  FIGS. 56 and 57 , the photodetectors  124  may be positioned externally of the valve. 
     During operation, the light source illuminates the inside/backside of the valve  26  which in turn reflects some of the light back to the photodetector as shown in  FIG. 60 , or lets light through to be received by the photodetectors as disclosed in  FIGS. 56 and 57 . When the valve is closed, most of the light coming from the source is reflected back to the photodetector (internal) or is not received by the photodetector (external). As the valve opens, more of this light is able to escape and as a result, less light is reflected back to the photodetector (internal), or conversely is received by the photodetectors (external). Through monitoring the signal coming from the photodetector, the degree to which the valve is open can be estimated along with the flow passing through the valve. The valve may be designed in such a way using shape and color as to focus the reflected light on the photodetector to certain degrees of its opening. The photodector  124  communicates with the computer  500  and processor  502 . 
     A physical shielding may be positioned within the valve. The LED can have an adjustable brightness so that during an initial calibration phase, the same baseline signal is achieved through increasing the brightness of the LED iteratively with feedback from the photodetector or choosing a wavelength of light that is not readily absorbed by the drugs used. Any wavelength may be used in this method although a wavelength that is minimally absorbed or reflected by the aerosol is preferred. A high pass filter may also be implemented to remove any signal contribution coming from DC power sources (flash lights, sunlight) as well as low frequency electrical lighting such as the 60 Hz (120 Hz) lights in North America and the equivalent frequencies around the world. 
     Alternatively or in addition to high pass filtering, the light source&#39;s brightness may be varied at a particular frequency and using frequency detection algorithms, this signal could be analyzed for flow. In this case, the amplitude of the frequency component of the signal that matches the frequency of the light source will decrease and increase as the valve opens and closes, respectively. 
     5.2. Shine Through in a Valve with a Slit 
     5.2.1. External Light Source 
     Referring to  FIG. 61 , a light source  122  is situated outside of and directed towards the valve  16  of the type in embodiment disclosed in Section 5.1, with the photodetector  124  remaining inside the valve pointed towards the light source. In this embodiment, the more the valve opens the opening  126 , the more light reaches the photodetector. Similar methods are applicable to this embodiment as they are in 5.1, including filtering and frequency encoding as well as some of 5.1.s vulnerabilities to drug interference. The photodector  124  communicates with the computer  500  and processor  502 . 
     5.2.2. Body Heat (Infrared) 
     Similar to the embodiments disclosed in Sections 5.1. and 5.2., and referring to  FIG. 62 , an infrared photodetector  128  is situated on the inside of a valve  16  of the type described in 5.1 and 5.2. Similar to 5.2, as the valve  16  opens, more light is allowed to reach the photodetector  128 . In this embodiment, the photodetector is selected such that it is most sensitive to infrared wavelengths emitted by the human body. As the infrared-opaque valve opens, more infrared light emanating from the user&#39;s mouth (mouthpiece device) or face (mask device) enters and is absorbed by the photodetector, or photodiode. The photodector  128  communicates with the computer  500  and processor  502 . This signal is analyzed by the microcontroller. 
     5.3. Oscillating Body 
     Referring to  FIG. 63 , a light source  122  and photodetector  124  are facing each other with an opaque body  96  in between. 
     The opaque body is free to move such that it may block the light from the source from reaching the detector in position  1  and allow the light to reach the detector in position  2 . 
     This opaque body is designed in such a way that it oscillates when flow is present and its oscillations are unique to different flow rates. The amplitudes of these oscillations are such that position  1  and position  2  are reached. The oscillating body may be a reed made of silicone or plastic, a moving vane, a rotating vane or a flapping piece of loose or stiff material, similar to that of a flag. This is not exclusive as any oscillating body may work. The signal coming from the photodetector is then continuously analyzed and the corresponding flow rate is inferred. The photodetector  124  communicates with the computer  500  and processor  502 . 
     6. Spring Displacement 
     The following embodiments rely on the movement of a spring (linear or non-linear, tension or compression) in response to either inhalation pressure or inhalation flow rate. As the spring moves from one position to another, it brings with it or activates a range of sensing hardware as follows: 
     6.1. Hall Effect 
     A magnet is positioned on the moveable end of the spring with a Hall Effect sensor at a fixed position. The Hall Effect sensor detects changes in the magnetic field as the magnet moves from one position to another, and this can be analyzed using various algorithms to determine flow. 
     6.2. Capacitance 
     A charged plate is positioned on the moveable end of the spring with an oppositely charged plate at a fixed position, separated by air (the dielectric). The capacitance changes as the charged plate on the spring moves and this can be detected using various hardware and software methods. 
     6.3. Reed Switches 
     A magnet is positioned on the moving end of the spring and a collection or magnetic reed switches are positioned along the length of the spring. As the spring deflects and brings the magnet with it, different reed switches are closed and by determining which switches are open vs. closed, the position of the spring and therefore the flow rate can be approximated. 
     6.4. Inductive Sensor 
     A conductive plate is positioned on the moveable end of the spring with an inductive coil producing and electromagnetic field in close proximity. As the distance between the coil and the plate changes, the inductance of the system changes which may be analyzed by software. This in turn can be used to approximate the position of the spring and therefore, flow rate. 
     7. Pinwheel Anemometer 
     7.1. A pinwheel is placed within the chamber such that its rotational speed changes with changing flow rate. The rotational speed of the pinwheel can be monitored by a rotating contact switch, periodic breaking of a light curtain or magnet and Hall Effect sensor combination and this speed can be used to approximate the flow rate through the chamber. 
     8. Heated Surface 
     8.1. Hotwire Anemometer 
     A wire or mesh is heated by applying a constant voltage across it. As air moves across this wire, it cools and its resistance drops. Since voltage remains constant, the current through the wire increases which can be monitored by electronics. The amount of current flowing through the wire is then used to infer flow rate. 
     8.2. Thin-film Flow Sensor 
     This is the same principle as the hotwire anemometer except that it is less intrusive. A thin film, heated sensor is placed on a surface within the chamber and the amount of current that flows through the sensor is used to determine flow rate. 
     9. Piezo Flex Sensor 
     9.1. Deflection Based 
     When airflow comes into contact with a body, the body exerts a force on the air to change its direction around the body. At the same time, the air imparts that same magnitude of force but in the opposite direction. Using this principle, a piezo flex sensor may be used such that as air impacts its surface, it is forced to deflect and the amount of deflection will be proportional to the amount of flow hitting the sensor. Piezo material generate a voltage under strain so strain can be detected and analyzed with various algorithms. Greater strain is a sign of greater flow rates. 
     9.2. Oscillation Based 
     Air flowing around a blunt object may generate vortices at a particular frequency as boundary layer separation occurs. This vortex shedding may induce vibrations in the object itself and if this object is made of a piezo-electric material, a voltage may be produced at a frequency matching that of the oscillating body. This signal may be analyzed and flow rates inferred using various algorithms. Alternatively, to amplify the signal, various objects may be used which cause vortex shedding at different frequencies at the same flow rate. When the shedding frequency matches the resonant frequency of the object, large amplitude oscillations will be induced which may be easier to detect and analyze. 
     10. Multistage Contact Switch 
     10.1. Different switches may be closed at discrete steps. Multiple printed conducting pathways could be printed onto a flexible surface and different switches will be closed at different positions of the flexible member. Based on which paths are closed vs open, the position of the member can be estimated and therefore the flow rate as well. 
     11. Potentiometer Vane 
     11.1. Using the forces generated by flow as described in embodiment 9.1., a vane may be designed such that it adjusts a potentiometer when flow is present. A biasing spring will make the position of the vane dependent on the flow present. The resistance of the potentiometer may be monitored continuously and the flow inferred based on this measurement. 
     MDI Actuation Detection 
     Detection of MDI actuation is an important piece of information that can be used for dose assurance and for providing feedback to the user about optimizing their breathing technique. Several characteristics of the MDI can be used and detected by an actuation detector, as described in various embodiments below, to detect the MDI actuation including the visual appearance of the aerosol plume, its sound, the temperature drop associated with rapid HEA propellant evaporation, its force to fire, the dielectric constant of the aerosol, displacement to fire, its pressure at actuation or communications with smart features on the MDI itself. 
     1. Light-Based Methods 
     1.1. Light Transmission (AKA Light Curtain) 
     Referring to  FIGS. 7 and 8 , in one embodiment, a light source (e.g., blue LED)  39  and a light detector (photodetector)  32  are spaced apart and oriented such that the source is directed towards the detector with an air gap in between, or such that light from the source may be detected by the actuation detector. Any wavelength in the visible spectrum and/or infrared spectrum may be used to detect MDI actuation. This air gap is large enough so that when an MDI is actuated, the aerosol plume is minimally impeded by the presence of the source and detector. As the aerosol plume travels between the source and detector, the amount of light originating from the source that reaches the detector will be reduced as the aerosol scatters and reflects light away. The result is an abrupt change in the output from the detector whose signal can be analyzed by various software algorithms. In particular, the aerosol drug particles scatter, reflect and/or absorb blue light to varying degrees within the interior space of the chamber. The change in light is detected by the photodetector, which communicates a signal to the processor. When no aerosol is present in the interior space, the photodetector records a baseline reading of receive light. When there is actuation, because of light scattering/reflection/absorption, the photodetector receives less or more light. Based on these parameters, the smart VHC may accurately determine the MDI actuation. This event may further be used to record a timestamp, which information may be useful for adherence tracking and monitoring. As shown in  FIG. 8 , the photodetector output over time shows a reliable indicator of actuations as evidenced by the periodic spikes on the timeline. 
     The wavelength of the light source can be any wavelength and ideally from the infrared bandwidth so that the light is not visible and distracting to the user. The sensitivity of the light detector should be such that it is most sensitive to light emanating from the light source. Ideal light sources have wavelengths in the infrared (wavelengths of 700 nm to 1 mm) or visible light (wavelengths 400 nm to 700 nm) spectra and are in the form of efficient Light Emitting Diodes (LEDs). 
     Ideal light detectors have highest sensitivity to the wavelength of the source light and can include photodiodes, phototransistors or light-sensitive-resistors (LSR). 
     1.2. Light Reflection 
     A light source and a light detector are oriented such that the detector will only receive light from the source when a reflecting body or media is present. When the aerosol plume is present, light from the source is reflected and at least a portion of this reflected light is absorbed by the detector. This spike in light absorption at the detector results in a change in voltage that can be analyzed by various software algorithms. Light source and detector should have the same properties as described in the Light Transmission embodiment. 
     1.3. Color Reflection 
     A white light source and a color sensor are oriented such that the color sensor will only receive light after the white light is reflected off of a body or media. When the aerosol plume is present, it reflects some wavelengths of light while absorbing others. The combination of all of the reflected wavelengths will dictate the aerosol plume&#39;s color which can be detected by the color sensor. The sensor can detect abrupt changes in light levels as well as abrupt changes in color which may be analyzed with various software algorithms to detect MDI actuation. 
     1.4. Camera and Image Processing 
     Cameras and image processing tools are used in a wide range of applications, identification of an aerosol plume can be one application. Various software algorithms may be used. 
     2. Sound-Based Methods 
     Referring to  FIGS. 24-28 , a VHC, or backpiece  8  coupled thereto, is configured with a microphone  82  (actuation detector), audio interface, visual feedback indicator  40 , microcontroller (which may be a processor  502 ), memory storage  504 , limit switch, Bluetooth/Wi-Fi connectivity and battery  503 , all of which may be housed in the backpiece  8 . The limit switch  62  detects the presence of an MDI, which triggers the electronic system to power up. The microphone and audio interface being recording sounds inside the interior cavity. When the MDI is actuated, the full soundwave of the actuation is captured by the microphone  82 , and stored into memory for analysis. 
     For all sound embodiments, a second microphone may be used to pick up ambient noise. The signal from this microphone may then be used for noise reduction purposes in the signal being analyzed. 
     2.1. Microphone—Simple Volume Threshold 
     A microphone is situated near the mouthpiece of the MDI and is at least partially insulated from sound from the outside environment. During MDI actuation, a relatively loud sound is produced as the drug is force out of the MDI orifice and this spike in volume can be detected using various software algorithms. 
     2.2. Microphone—Volume Threshold with Pre-filtering 
     A simple volume threshold method is subject to false triggers as a result of any loud sound from the environment that is not adequately dampened by the sound insulation. To further reduce the risk of a false trigger, a volume threshold can be combined with pre-filtering the incoming microphone signal. 
     The sound produced during a MDI actuation is comprised of various sound frequencies. Using low pass, high pass or band pass filters, the microphone signal can be tuned such that only frequencies associated with a MDI actuation are listened too. This limits the possibility of false triggers to loud sounds that are within the sound bandwidth of the MDI actuation. 
     A microphone is situated near the mouthpiece of the MDI and is at least partially insulated from sounds from the outside environment. The output signal of the microphone passes through a series of carefully selected resistors, capacitors and/or inductors arranged in such a way as to construct low and/or high pass filters. After passing through these filters, the signal is analyzed by the microcontroller ( FIG. 28 ) or other processor  502  for spikes in volume which can be detected using various algorithms. Frequency filtering may also be accomplished digitally. 
     2.3. Microphone—Target Signal Comparison (Filtered and Non-Filtered) 
     Both methods (2.1. and 2.2.) are subject to false triggers as a result of loud ambient sounds. Instead of, or in conjunction with, simple volume thresholds, quantitative comparison between the incoming sounds with a pre-defined target can nearly eliminate the risk of false triggers. Autocorrelation and minimizing root-mean squares are a few algorithms based in the time domain that can be used for signal comparison and both of these may be combined with analog or digital filters as described in 2.2, or with no filtering at all. Frequency domain algorithms can also be used for comparing a source to a target. 
     3. Temperature Change Methods 
     3.1. Temperature Sensor and Direct Contact Evaporation 
     MDI&#39;s typically contain a propellant, for example Hydrofluoroalkane (HFA), which has a low boiling point. During MDI actuation, some of this propellant is able to escape the MDI in its liquid phase. When this liquid propellant is exposed to the outside environment, it rapidly evaporates as a result of its low boiling point and minimal vapor pressure of the propellant in the surrounding atmosphere. Through evaporative cooling, a rapid drop in temperature arises in all material in which the liquid propellant is in contact with. 
     Referring to  FIGS. 38 and 39 , one embodiment of a VHC and/or MDI is configured with one or more temperature sensors  140  (actuation detector), for example coupled to, or embedded in, the wall of the holding chamber, or disposed in the interior space thereof, for example on the inhalation valve or baffle at the output end of the chamber housing. The temperature sensors may be a temperature sensitive resistor, thermocouple, thermistor or infrared temperature sensor to detect rapid drops in temperature and subsequent warming. Alternatively, a rapid drop in temperature alone could be sufficient. This rapid temperature drop and/or rewarming can be detected using various software algorithms. In this embodiment, the temperature sensor is placed in the path of the aerosol plume such that a certain amount of the liquid propellant is deposited onto its surface. Care is taken to avoid any substantial drug loss from the sensor being in the aerosol path. A sensor with minimal thermal mass is ideal to promote rapid detection of temperature changes. As shown in  FIG. 39 , various minimum plume temperatures may be associated with various MDI formulations. The temperature data may then be input to the microcontroller or other processor  502  (not shown) to indicate and record MDI actuation. 
     3.2. Temperature Sensor and Air Temperature 
     The embodiment of 3.1. requires the temperature sensor to be in the aerosol path during MDI actuation. Alternatively, rapid drops in air temperature may be monitored since the evaporation of the propellant would cause a decrease in the surrounding air temperature as well. For example, as shown in  FIG. 38 , the sensor  140  may be located outside the interior space of the holding chamber, for example on the MDI. This would allow for a non-invasive method of MDI actuation using temperature. The position of the temperature sensor should be proximal to the MDI since the magnitude of the temperature drop decreases as distance from the MDI increases. This is a result of most of the propellant evaporating prior to travelling large distances. A ratio of temperatures at different distances from the MDI or a profile of temperatures vs. distance may also be evaluated using multiple temperature sensors positioned along the chamber for more confidence in detecting MDI actuation. 
     3.3. Temperature Sensor on the MDI 
     As shown in  FIG. 38 , immediately following actuation, the propellant is not in phase equilibrium. This causes some of the liquid propellant to evaporate until saturation occurs and equilibrium is restored. The evaporation causes the temperature of the canister to drop which can be detected using a contact temperature sensor or any other sensor mentioned in embodiment 3.1. This could be integrated into the MDI adapter or an over-the-counter add on to the MDI canister with wireless communications capability to communicate with the MDI adapter. The temperature data may then be input to the microcontroller or other processor  502  (not shown) to indicate and record MDI actuation. 
     4. Force to Fire 
     4.1. Local Force Peak Detection 
     Referring to  FIGS. 40-42 , a force sensitive resistor (FSR), or actuation detector, situated at the top or base of the MDI boot may be used to determine a force measurement and to detect the actuation of the MDI. When looking at a force vs. displacement curve for a canister in a boot as shown in  FIG. 42 , there can be a peak or other signal change at the point of actuation that may be detected using the FSR and various algorithms. Several types of force sensors can be used in addition to FSR including strain gauges, spring-displacement, piezo-flex sensors and others. As shown in  FIG. 40 , a force sensor  160  is located on a support flange of the backpiece  8 . In  FIG. 41 , the force sensor  160  is located on a cap  164  coupled to the backpiece with a tether  162  and secured to the top of the container  28 , where it is engaged by the user during actuation of the MDI. The force sensor  160  communicates a signal to the computer  500  and processor  502 . 
     4.2. Force Threshold 
     A simple force threshold may also be used instead of a peak finder although there would be less certainty with this method. 
     5. Capacitance Change 
     5.1. One factor that affects the capacitance of a capacitor  106  is the dielectric constant of the material between the two charged surfaces. Assuming the dielectric constant of medical aerosols is different from that of air, a change in capacitance of an integrated capacitor may be used to detect MDI actuation. Referring to  FIGS. 43 and 44 , the capacitor would have an open air gap that is easily infiltrated by the aerosol from the MDI. The capacitor may be located at the output end, as shown in  FIG. 43 , or the input end, as shown in  FIG. 44 . The capacitance would then be monitored for changes using an oscillating or charge/discharge circuit whose abrupt change in frequency would signal the MDI actuation. This could be detected using various software algorithms. The capacitor communicates with the computer  500  and processor  502 . 
     6. Displacement to Fire 
     6.1. Magnetic Cap and Reed Switch 
     Referring to  FIGS. 45A  and B, a canister cap  170  is fitted securely over the MDI canister, in a similar position to a dose counter, and travels with the canister during actuation. The cap has magnetic properties by means of embedding a permanent magnet within its structure, having magnetic ink printed on it or being produced from a magnetic material. Within the MDI adapter is a Hall affect sensor or reed switch  172 . When the MDI canister is depressed to its actuation position, the reed switch closes and this is detected by software. Using a Hall Effect sensor, the signal can be analyzed for a plateau which would signify the bottoming out of the MDI canister, or change in X, and the point of actuation. The sensor communicates with the computer  500  and processor  502 . 
     6.2. Conducting Cap and Inductor 
     Similar to embodiment 6.1., a cap is sold with the VHC. In this embodiment, the cap has conductive properties and is not necessarily magnetic. An oscillating electromagnetic field is produced by an inductor within the chamber which induces a current in the MDI canister cap. As the cap moves closer to the inductor during actuation, the inductance of the system changes which can be detected and analyzed. Once a plateau in the signal is reached signifying the canister bottoming out, an actuation can be registered by the software. 
     7. Pressure Detection 
     When the MDI is actuated, its pressurized contents are forced out of the nozzle and into the VHC. The pressure wave that accompanies this may be detected with a pressure transducer  78  placed within the chamber or near the mouthpiece of the MDI itself as shown in  FIG. 18 . In particular, one or more pressure sensors  78  are disposed on or along an interior surface of the wall in the interior space of the chamber. Referring to  FIG. 20 , pressure sensor output v. time illustrates when actuation occurs as evidenced by the spike. 
     Referring to  FIGS. 46 and 47 , a pressure sensor  78  may be disposed at the input or output ends of the holding chamber in the interior space. The sensor detects and records the pressure differential. 
     Referring to  FIG. 48 , one or more flow channels  84  are positioned adjacent the support block  86 , with its discharge orifice  88 . Ambient air is entrained through the flow channels, which provide a flow path of known resistance. A pressure sensor  78  records the pressure difference. 
     Referring to  FIGS. 49 and 50 , a restrictive orifice is created in a bypass channel. The pressure drop across the restrictive orifice may be detected and recorded by a pressure sensor, and then correlated with the flow rate. The various pressure sensors communicate with the computer  500  and processor  502 . 
     8. Communication with Smart MDI 
     8.1 Referring to  FIG. 78 , an MDI may be configured with a dose counter module  90 , which has been actuated for the purpose of adherence monitoring and captures dose actuation time, count and total. At the same time, the VHC may be configured with a flow detection module  92 , which captures inhalation time, duration and count, with the modules being in communication, for example with Bluetooth technology. Communications with these devices from the smart VHC or its application can be used to detect and confirm MDI actuation and technique. 
     Referring to  FIG. 13 , the actuation of the MDI is detected by receiving a single from a transmitter  221  placed on top of the MDI canister. Upon actuation, the transmitter outputs a signal that is received by the smart VHC. For example, a piezoelectric disk mounted to the top of the canister, either incorporated into a dose counter coupled to a container or as a separate element, generates enough voltage when pressed to power the transmitter. Several types of transmitter/receivers are possible including IR LED/photodiode, radiofrequency (RF) Tx/Rx or tone generator/microphone. Depending on the type of Tx/Rx, this system may also be used to identify the MDI type, with different RF frequencies being used for controller/rescue inhalers. 
     MDI Insertion 
     Providing feedback and confirmation to the user that the MDI has been properly inserted may be a desirable feature of the smart VHC. Additionally, depending on the method used, this feature may govern when the microcontroller or other processor  502  is in a sleep state, further extending the battery life of the device. As an example, when the MDI is inserted, the microcontroller wakes up and draws more current from the power source to power its sensors, displays and communications. Once removed, the microcontroller goes back into a low energy state. 
     1. Switch 
     1.1. Limit/Contact Switch 
     In this embodiment, as shown in  FIGS. 19 , a limit switch  62  (mechanical), or contact switch, is placed within the backpiece  8  in such a way that upon insertion of the MDI, the switch is closed. The limit switch completes the circuit when the MDI is inserted. The closing of this switch triggers an interrupt in the microcontroller or other processor  502  and permits it to operate in its fully operational state at which point the user is notified through visual or audio cues that the MDI has been fully inserted. When the MDI is removed, the switch opens, prompting the microcontroller to return to its state of low energy requirement. In one embodiment, if the device is inactive for a predetermined time period, e.g., approximately 30 to 120 seconds, the microcontroller may enter into a sleep mode. The predetermined time period may be set/programmed by the user. 
     In addition to a contact switch, and referring to  FIG. 11 , a button may be used to power on/off the system. An audio or visual feedback mechanism, e.g., visual or auditory indicator such as lights and/or an alarm, may be implemented using various LEDs, speakers, and haptic and/or visual displays/indicators. 
     1.2. Reed Switch 
     Similar to embodiment 1.1, and referring to  FIG. 74 , a portion  200  of the MDI is magnetized either with magnetic ink, electromagnets or permanent magnets. When the MDI is inserted, a reed switch  202  is closed. The closing and opening of this switch have identical consequences for microcontroller operation and user feedback as described in 1.1. 
     1.3. Conductive Path 
     In this embodiment, as shown in  FIG. 75 , a portion of the MDI, for example the mouthpiece, has an electrically conductive path  204  which, when inserted into the MDI adapter, completes a circuit  206  within the MDI adapter electronics. This circuit is used to provide feedback to the user and enable full functionality of the microcontroller as described in 1.1. 
     2. Light Curtain 
     2.1. A light curtain, as disclosed previously, may be used to determine insertion of the MDI into the MDI adapter. In this embodiment, an LED and photodiode are placed opposite each other across the MDI adapter opening. When no MDI is inserted, light from the LED is able to reach the photodiode. Once the MDI is inserted, this light transmission is interrupted which may be detected by the microcontroller and used to provide audio or visual feedback to the user assuring proper insertion of the MDI. 
     3. Detection of Mouthpiece Shape 
     3.1. Strain Gauge 
     Strain is introduced in the MDI adapter or backpiece as shown in  FIG. 70  as the material deforms in order to accommodate the MDI mouthpiece shape. The amount of strain can be measured using strain gauges  206 . Monitoring the strain of the MDI adapter can provide a way to detect whether an MDI has been inserted into the MDI adapter. Once strain reaches a certain threshold value, the system can provide feedback to the user to confirm MDI insertion. 
     3.2. Force Sensitive Resistors (FSR) 
     Force sensitive resistors  208  may be placed on or within the MDI adapter or backpiece  8  as shown in  FIG. 72 . Upon MDI insertion, the MDI mouthpiece exerts a force against the FSR which produces a voltage change that is evaluated by the microcontroller. Depending on the signal coming from the FSR, insertion of the MDI can be concluded and this information relayed back to the user. 
     3.3. Linear Action Potentiometers 
     Linear action potentiometers  210  may be positioned on or within the MDI adapter or backpiece as shown in  FIGS. 69 and 71 . Upon MDI insertion, the potentiometer is displaced which produces a voltage change that is evaluated by the microcontroller. Depending on the signal coming from the potentiometer, insertion of the MDI can be concluded and this information relayed back to the user. 
     3. Image Processing 
     4.1. A camera or series of cameras may be used to determine how far a MDI has been inserted into the MDI adapter. Various image processing algorithms may be used to determine this and once confirmed, this information may be relayed back to the user. 
     Power Supply and Distribution 
     Problem Identification 
     All embodiments require the use of electrical power for functionality. Various power supplies may be used on their own or in combination with other sources. Sensors and feedback methods may receive power even if they are on separate chamber components. 
     Power Supplies 
     1. Batteries (Single or Multiple Batteries May be Used for Each) 
     1.1. Permanent, disposable 
     The power supply may be such that once the battery has been depleted, the entire electronic device is disposed of. The battery would be permanently enclosed within the electronics body such that access is restricted without damaging the device. 
     1.2. Replaceable 
     The power supply may be such that once the battery has been depleted, the user is able to access the battery cartridge and replace the depleted cells with full ones. This is similar to many children&#39;s toys or watch batteries. 
     1.3. Rechargeable 
     The battery may be rechargeable such that once the battery has been depleted, the user can simply recharge it through a DC power jack, USB or other method. Additionally, the battery may be trickle charged throughout its life which can extend its depletion time. Trickle charging refers to charging a battery continuously or periodically with a very small current. Alone, this type of charging would take a very long time to completely recharge a depleted battery but it is useful for extending battery life, especially when charging occurs continuously. 
     2. Photovoltaic Cells 
     2.1. Photovoltaic cells generate a voltage in response to light. This may be used to power the device directly depending on the power requirements of the sensors and features or to recharge a battery or super-capacitor. 
     3. Rectenna 
     3.1. Rectennas use ambient radio-frequency energy from that of radio transmissions, mobile communications, Wi-Fi networks, etc. to induce small currents within an antenna which are rectified and managed in such a way that they may be used to trickle charge a rechargeable power source. 
     4. Shake-to-Charge 
     4.1. Incorporating a freely mobile magnet within conductive coils will allow the system to generate current in the conductive coil when the device is shaken or the magnet is forced to move by other means. The motion of the magnet induces a current in the coils which may be used to charge a battery or other power source. 
     Distribution 
     It is preferable to have all electronic components in close proximity to one another to make the distribution of power easier to manage. However, given the requirements of the device, this may not be possible. In the cases where some electronics are housed in the MDI adapter and others are housed towards the mouthpiece or mask adapter, a few power distribution strategies exist. 
     1. Conductive Paths Along Body 
     1.1. This method uses only one power source (e.g. one battery) located in either the mouthpiece/mask adapter or the MDI adapter whose power is transferred to the other component through the body. In each case, contacts at both ends of the body ensure the power is reliably transmitted to the other components. The contacts are formed in such a way as to still allow assembly and disassembly of the device for cleaning while providing repeatable, robust connections on each assembly. These conductive paths are also used for data communications between the hardware at the front and the microcontroller at the back. 
     1.1.1. Conductive Resin 
     Conductive resin may be used to mold conductive pathways directly into the body component. This would be done through a dual-shot or insert molding manufacturing method. 
     1.1.2. Conductive Ink 
     Conductive ink may be used to form the conductive path and can be either pad printed or screen printed onto the body. 
     1.1.3. Flexible Electronics and Adhesive 
     Flexible, low profile wires may be used and these could be secured to the body through the use of an adhesive. 
     2. Two Batteries with Wireless Communications 
     2.1. The hardware at the mouthpiece/mask adapter end of the VHC may be powered by a completely independent power source (e.g. battery) from the power source at the MDI adapter end of the VHC. Each end of the chamber would likely require its own microcontroller or other processor  502  to handle inputs and outputs at those respective ends. It is very likely in this scenario that the two microcontrollers would need to communicate to share data. This could be done via Bluetooth or other means. 
     MDI Identification 
     Identification of the MDI provides assurances to the patient, prescriber and payer that the approved medication regimen is being adhered too. Additionally, it may be used to alert the patient if the wrong drug has been inserted into the chamber which may help in preventing over and under dosing of particular medications. The methods of identification below may be used on their own but may also be used in combination to confidently identify the MDI. 
     For example, and referring to  FIG. 13 , a photodiode  222  and color detector sensor  224 , or MDI identifier, may be disposed on the exterior surface of the chamber housing wall, or on the backpiece, and be directed toward the MDI, including the actuator boot and container. A unique tag may  226  be attached to each MDI, or a unique rescue tag may be attached to a rescue MDI and a unique controller tag attached to a controller MDI. The sensor  224 , e.g., color detector sensor, detects the presence of the tag to identify each specific MDI or to identify each MDI by category, e.g., rescue or controller. The tag may be configured with different colors, barcodes, magnetic properties, surface properties such as reflection/absorption etc. 
     1. Color Sensing of MDI Boot 
     1.1. Mouthpiece Color 
     Referring to  FIG. 68 , MDI&#39;s come in a variety of different colors and some have two color tones differentiating the handle from the mouthpiece. Color sensing may be used to help identify the MDI that is inserted into the MDI adapter by getting a specific color code reading (e.g. RGB, CMYK, L*a*b*) from the mouthpiece portion of the MDI. As the MDI is inserted into the adapter, the color sensing hardware, or sensor  224  (MDI identifier), is triggered to collect the color information from the mouthpiece of the MDI. This color code is then analyzed through software and compared to a database of MDI and their respective color codes. Various algorithms may be used for the comparison and the closest match is used for the MDI identity. Alternatively, the MDI boot color code may be used as an input to a multifactorial algorithm which uses several inputs to identify the MDI. 
     1.2. Handle Color 
     As shown in  FIG. 68 , similar to the mouthpiece color sensing but instead of having the color sensor  224  positioned to obtain the mouthpiece color code, it is positioned to analyze the color of the handle portion of the MDI boot. 
     1.3. Mouthpiece and Handle Colors 
     Combining 1.1. and 1.2. to help differentiate two-tone MDI boots. 
     2. Color Sensing of Aerosol Plume 
     2.1. There are numerous formulations across all MDI and this may be reflected in different color codes of the aerosol plume. Color sensing hardware is positioned near the mouthpiece of the MDI boot within the MDI adapter and during MDI actuation, the color code of the aerosol plume is collected and compared to a database of various MDI. Various comparison algorithms may be used with the closest match being used for MDI identification. Alternatively, the aerosol color code may be used as an input to a multifactorial algorithm which uses several inputs to identify the MDI. 
     3. Mouthpiece Shape Detection 
     3.1. Force Sensitive Resistors (FSR) 
     Referring to  FIG. 72 , FSRs  208  are positioned in the MDI adapter such that during MDI insertion, the resistors are compressed by an amount proportional to the size of the MDI mouthpiece in that particular direction causing their signal to change accordingly. Their resistance values are compared to those of the MDI in a database. Various comparison algorithms may be used with the closest match being used for MDI identification. Alternatively, the resistance values may be used as an input to a multifactorial algorithm which uses several inputs to identify the MDI. 
     3.2. Strain Gauges 
     The MDI adapter port is intentionally undersized such that it must stretch as MDI are inserted, as shown in  FIG. 70 . The total strain and locations of high and low strain detected by the strain gauges  208  may be analyzed and compared to a database of different MDI and their strain values to help identify the MDI. 
     3.3. Referring to  FIGS. 69 and 71 , and linear action potentiometers  210 , similar to the FSR method, potentiometers which are adjusted through linear-motion are adjusted according to the size of the MDI mouthpiece in a particular direction. The resistance values gathered by the system upon MDI insertion are compared to values stored in a database for various MDI. These potentiometers have a biasing spring so that they return to their original positions when the MDI is removed. 
     4. Mouthpiece Length 
     4.1. Tactile or Slide Potentiometer 
     The length of the mouthpiece portion of the MDI may be used as a distinguishing factor. 
     Upon full insertion into the MDI adapter, the length of the mouthpiece may be measured by means of a tactile or slide potentiometer and compared to the various lengths stored in the system&#39;s database as shown in  FIG. 69 . 
     5. Resistance to Flow Profile 
     5.1. Resistance to Flow Profile 
     Referring to  FIGS. 54 and 55 , flow through the chamber may monitored as disclosed herein by way of various sensors. The flow may be used to help identify the MDI. Using this flow information coupled with data from a differential pressure sensor  78  comparing the pressure at the MDI mouthpiece to atmospheric pressure, the Pressure vs. Flow profile can be collected for the MDI. Comparing this profile to those in a database of MDI, a match can be found which could identify the MDI. Alternatively, the resistance profile may be used as an input into a multifactorial algorithm. 
     6. MDI Sound at Certain Flow Rate 
     Referring to  FIGS. 24-28 , an audio interface includes an equalizer circuit (e.g., 7-band), which divides the audio spectrum into seven bands, including for example but not limited to, 63 Hz, 160 Hz, 400 Hz, 1 kHz, 2.5 kHz, 6.25 kHz and 16 kHz. The seven frequencies are peak detected and multiplexed to the output to provide a representation of the amplitude of each band. The bands are processed by the microcontroller to average the bands into a single amplitude (dB) v. time signal ( FIG. 25 ). The unique sound produced by different brand MDI&#39;s may then be compared to a known stored sound within the memory or cloud database. Using normalized correlation, the input sound may be compared to the reference sound with a high degree of certainty. The actuation sound is captured and stored upon MDI actuation, and the comparison and determination may be processed after a treatment, in order to free up processing power for other VHC tasks during treatment, or during treatment, depending on the available processing power. If processing is fast enough, the MDI actuation may be analyzed in real time, and provide feedback about whether the MDI nozzle, or support block, is plugged or partially plugged due to low or insufficient sound produced. The feedback may also include information about whether the MDI needs to be shaken and/or primed, or checked for adequate remaining dose counts. 
     6.1. A database may be generated which contains the frequency spectrum or dominant frequencies of all MDI at specific flow rates. In use, when this flow rate is reached, the sound is sampled through a microphone and compared to the sound profiles stored in the system database. Various algorithms may be used for this comparison. 
     7. MDI Sound at Actuation 
     7.1. A database may be generated which contains the frequency spectrum or dominant frequencies of all MDI actuation sounds. When actuation occurs, the recorded sound is quantitatively compared to those stored in the system&#39;s database and the closest match is determined. 
     8. MDI Sound when Percussed 
     8.1. A database may be generated which contains the frequency spectrum or dominant frequencies of all MDI sounds when percussed or hammered on. Upon insertion into the MDI adapter, a mechanical hammer is triggered such that it impacts the MDI in the mouthpiece region. The sound that is generated is dependent on the shape, volume, stiffness of the MDI boot and its fit with the MDI adapter. This sound can then be compared quantitatively to those in the system&#39;s database. 
     9. Image Processing 
     9.1. Read the Label 
     Use text recognition software to “read” the text on the MDI boot and/or MDI canister. For example, and referring to  FIG. 4 , the camera  35 , or other image sensor (MDI identifier), is mounted to the chamber housing, for example adjacent the input or output ends thereof, or at any location therebetween. The image sensor may also be coupled to the mouthpiece assembly or to the backpiece. The camera or image sensor captures an image of the MDI, including various textual information presented on a label  240  coupled to the container and/or actuation boot. An image processing algorithm and/or machine learning technique may be used to extract the textual information, unique shape and/or unique feature that reveals the type and identify of MDI being associated with the VHC. The captured image may further be stored into memory and compared with different types of MDI&#39;s in a database to narrow the selection. Referring to  FIGS. 5A, 5B and 6 , the camera or image sensor capture the image of the MDI and converts to a greyscale image  242  as shown in  FIG. 5B . The processor then extracts a plurality of templates (e.g., three) from the captured greyscale image and compares the templates/image with stored images in a database. As shown in  FIG. 6 , the processor correctly identified the MDI, referring to label  244 . 
     9.2. Combine Color, Shape 
     Analyze color and shape from a digital image or series of digital images and compare these to colors and shapes of various MDI in a database. 
     9.3. Feature Recognition 
     An image kernel may be used to scan the image for similarities to the kernel itself. For example, a kernel in the form of a GSK label may be used to identify GSK boots by computing the correlation product for each position of the kernel on the image and checking to see if the correlation coefficient exceeds a certain threshold value which would indicate good agreement. 
     10. Spectroscopic Drug ID 
     10.1 Single Wavelength Infrared/UV 
     Infrared and ultraviolet spectroscopy are methods used to determine the chemical structure and makeup of a sample. All chemicals absorb infrared and ultraviolet radiation to some degree and will absorb some wavelengths of light more than others depending on the bonds present in their chemical structure. Using a light source of a controlled wavelength, the absorbency of the drug to that particular wavelength can be analyzed by shining the light through the aerosol towards a light detector. This absorbency can then be compared to values in the MDI database. 
     10.2. Multiple Wavelength Infrared/UV 
     Similar to 10.1. except that multiple wavelengths may be used. 
     11. Force to Fire 
     11.1. Using a force sensitive resistor (FSR), the force at MDI actuation can be determined. This would need to be coupled with MDI actuation detection as described herein. As soon as MDI actuation is detected, the force is recorded and compared to values stored in the MDI database. 
     12. Temperature of Aerosol (Aerosol/Air Temperature or Contact Evaporation) 
     12.1. Single Point 
     Temperature can be monitored at a fixed distance from the MDI and using the temperature detected during MDI actuation, this information can be compared to temperatures stored in the system&#39;s MDI database. Despite all MDI using the same family of propellant (HEA  134   a  or HFA  227 ), temperature differences of the aerosol are seen at fixed distances from the MDI as a result of the different drug formulations. 
     12.2. Temperature Vs. Distance 
     Further to embodiment 12.1., several temperature sensors may be used at fixed distances from the MDI to collect a temperature profile during MDI actuation. This profile may be used and compared to profiles in the system&#39;s database. 
     13. RFID on MDI from Supplier 
     13.1. Referring to  FIG. 73 , Radio Frequency Identification (RFID) tags or labels  252  may be adhered to or molded in to the MDI by the manufacturer or supplier of the medication. In this case, it is possible to read the RFID label on the MDI with an RFID reader  250  within the MDI adapter or coupled to the backpiece  8  or other component of the VHC. 
     14. RFID on Dose Counter (Integrated or OEM) 
     14.1. Similar to embodiment 13.1., RFID tags may be incorporated into integrated or dose counter modules and these may be read with the RFID reader incorporated with the chamber. 
     15. Label Placed on MDI by User 
     15.1. RFID 
     Similar to embodiments 13.1. and 14.1., a RFID tag may be read from the MDI. In this embodiment, the RFID comes in the form of a sticker, adhesive patch or other form that is placed on the MDI by the user. 
     15.2. Bar Codes (1D and 2D) 
     Similar to embodiment 15.1. except a bar code may be used in place of a RFID. The chamber then includes a bar code scanner as opposed to a RFID reader. 
     16. Access Patient Medication List on Cloud 
     16.1. Bluetooth/Wi-Fi Access 
     A user&#39;s digital medical records may be accessed through the internet and their MDI medication prescriptions may be used to help identify the MDI being used with the VHC. Alternatively to ensure security, the healthcare provider or payer may initiate a ‘profile’ for the user and select their MDI medication(s), which will then be communicated to the VHC via Bluetooth or Wi-Fi. 
     17. Communication with Smart Inhalers 
     17.1. Bluetooth/Wi-Fi Communications 
     Smart inhalers are already used to track adherence of MDI. Communication with these inhalers will allow the VHC to directly identify the MDI being used. This may be accomplished through Bluetooth or Wi-Fi communications. 
     18. Manually Selected by User 
     18.1. Manual Selection 
     Referring to  FIG. 19 , user input buttons  260 , for example with different colors, shapes or indicia. The user  66  would push the appropriate button, e.g., blue, associated with a rescue MDI, or red, associated with a controller MDI. A combination of pressing both buttons would communicate a combination MDI was being used. Each button may also have a visual indicator, such as a light, which illuminate, and stay illuminated for a predetermined time period (or until the treatment is completed), when pressed. If the wrong indicator is displayed, it provides indicia to the user to start over. A single button may also be used, with a button push being associated with one of the rescue or controller MDI, and with no button push being associated with the other type of MDI. When reviewing patient use data, the prescriber would know which type of drug is associated with each of the rescue and controller MDI&#39;s. In addition, the user may input the drug information through an application on a computer, for example in a user profile setting. The user may share the logged medication activity with the prescriber and/or payer. 
     The user may be given the option of manually selecting the MDI being taken. This may be done at each dose or the list of medications may be specified by the user once upon receiving the smart chamber. For users with only one prescribed medication, the latter method would serve to confidently identify the MDI being used every time whereas for users with multiple medications, this would be used to short list the possible MDI candidates which would then need to be further identified by the system using means described in other embodiments. 
     19. Capacitance/Dielectric Constant Detection 
     19.1. Dielectric Constant Detection 
     Two oppositely, electrically charged features are separated by an air gap forming an open capacitor. Upon MDI actuation, this air gap is infiltrated with aerosol. Assuming that aerosols have different dielectric constants from one another, the capacitance change of the open capacitor can be measured and this capacitance value can be matched to those in a database of known aerosols and used to identify the MDI. 
     20. Resonant Frequency of MDI 
     20.1. A sound generator is located within the VHC which produces a range of frequencies in a sweeping fashion. When the resonance frequency of the MDI is produced by the sound generator, a spike in volume may occur which can be detected by means of a microphone. 
     21. Infrared Reflection of MDI Boot 
     21.1. Using infrared (IR) emitter(s) and IR detector(s), an infrared “signature” may be generated for various MDIs. The IR emitter(s) and detector(s), and positioning thereof, may be the same as the white LED and color sensors discussed above and shown in the attached Figures. IR Radiation is directed towards the mouthpiece and/or handle portion of the MDI boot and the amount of radiation absorbed/reflected is used to identify the MDI. Specifically, in this embodiment, the amount of radiation reflected is detected by the IR detector and this value is compared to those present in a prerecorded MDI database. The material of the MDI boot, its shape and surface finish all play a role in the amount of reflected IR radiation. A single wavelength IR LED/Detector may be used or several IR LED/detectors with different IR wavelengths may be used. 
     Mask Force and Seal Feedback 
     When delivering respiratory medications to users, facemasks  600  are often used. For example, facemasks may be coupled to the mouthpiece assembly  12 , or output end, of a VHC  3 . In order to maximize the drug delivery, it is important to ensure that a proper seal is formed between the mask and the user&#39;s face  602 . The proper seal may be determined by measuring the force applied to the mask, VHC or other delivery device, e.g., nebulizer or OPEP device, or by registering contact between the mask and the user&#39;s face. 
     In one embodiment, shown in  FIG. 29 , a medication delivery system includes a medication delivery device, e.g., VHC, having an input end  10  and an output end  14 . A mask  600  is coupled to the output end. The mask, and delivery device, are moveable along a longitudinal axis  6  to an engaged position with a user&#39;s face  602 . A force sensor  604  is disposed between the mask  600  and the input end  10  of the medication delivery device. For example, the force sensor  604  may be mounted between the mask  600  and the valve assembly  12  (e.g., mouthpiece assembly), or between the valve assembly  12  and the chamber housing  2 . The force sensor  604  may be a load cell that converts mechanical deformation or displacement into electrical signals via a strain gauge, or a piezoelectric sensor that converts changes in force into electrical change through a piezoelectric effect. The force sensor communicates a signal to the computer  500  and processor  502 , which may be mounted, for example to the backpiece  8 . The VHC microcontroller monitors the force being applied and provides feedback to the user, or caregiver manipulating the delivery device, to either increase, decrease or maintain the force being applied. For example, the force required to achieve a desirable seal may range between 1.5 and 7 lbs. Feedback to the user includes an indicator, whether a visual indicator  40  (e.g., LED), an auditory indicator (speaker) or vibration indicator. The force sensor  604  is responsive to the force being applied along the longitudinal axis to the mask by the medication delivery device. The indicator provides feedback to the user regarding the amount of force being applied to the mask, whether too little or too much, and/or not uniform around the periphery. 
     In another embodiment, shown in  FIGS. 30 and 31 , contact sensors  608 ,  610  may be incorporated into the mask  600  to monitor, sense and signal appropriate contact with the user&#39;s face around a perimeter of the mask. For example, the mask is configured with a sealing portion  612  adapted to engage the face  602  of the user. The sealing portion  612  may include a turned-in C-shaped lip, terminating at a free end  615 . One or more sensors  608  are coupled to the sealing portion, wherein the force sensor is responsive to a force being applied to the sealing edge. In one embodiment, a plurality of sensors are embedded in the sealing portion, and are distributed around the periphery of the mask, or a length of the sealing portion, in spaced apart relationships as shown in  FIGS. 30 and 31 . In an alternative embodiment, shown in  FIG. 30 , the sensor  610  comprises a continuous strip extending around the sealing edge. 
     Referring to  FIGS. 30 and 31 , an indicator  616  is in communication with the sensor and is adapted to provide feedback to the user regarding the amount of force being applied to the sealing edge, or whether contact has been made with the user&#39;s face. For example, the indicator may include a visual, auditory or vibratory indicator. In one embodiment, the visual indicator includes a plurality of lights  616  (e.g., LED&#39;s) distributed and spaced apart along the sealing edge, or the periphery of the mask. In one embodiment, the plurality of visual indicators are associated respectively with, and directly coupled to, the plurality of sensors. 
     In operation, and referring to  FIGS. 32 and 33 , the user or caregiver applies a force to the mask  600 , engages the user&#39;s face  602  with the sealing edge  612  of the mask, senses the force being applied to the mask, or alternatively that contact is being made at a particular location on the sealing edge, and provides feedback to the user with an indicator  616  about the force and/or contact being applied. The user/caregiver may then adjust the force being applied to the mask. In one embodiment, the feedback would be illumination of the lights  616  that are coupled to contact sensors  608 ,  610  where contact has been detected, and with lights not illuminating where contact has not been detected. Similarly, a portion of indicator lights may illuminate where various force sensors have detected a sufficient force has been applied, and lights not illuminating along portions of the mask where insufficient force is being applied. In other embodiments, the lights may illuminate in different colors, or turn off, if too much force is being applied. 
     Once active, the controller (which may be implemented to include one or more computer  500  elements such as a processor  502  ( FIG. 83 )) may analyze the output of the force or contact sensor and estimate the quality of the seal. Combining the measurement of force being applied, together with a measurement of the contact with the user&#39;s face, allows the device to provide information about whether an adequate seal is formed. 
     Active Valve 
     When using various medication delivery devices, such as a VHC, a slow inhalation (&lt;30 L/min maximum), followed by a breath hold, may improve significantly lung deposition of the drug. While various auditory aids are available to provide feedback to the user that the inhalation rate is too high, they are passive, and do not control the rate. As such, they may be misunderstood or confused with positive feedback (e.g., inhaling quickly to make the whistle sound is good, rather that the intended feedback that the sound should be avoided). 
     As shown in  FIGS. 34-37 , one embodiment of a valve  700  actively adjusts the resistance to opening or closing during inhalation (or exhalation) so as to actively control the inhalation or exhalation rate. The system may also provide feedback to the user that the valve is actively controlling flow so that the user may adjust the flow rate. 
     The valve may be configured in various forms, including an annular doughnut valve, as shown in  FIGS. 35 and 36 , as a duckbill valve  720 , as shown in  FIG. 87 , or as other valves with moveable, bendable or deformable features. The annular valve includes a central opening  702  and an annular flange  704  that bends or deforms outwardly such that the flange is lifted off of a valve seat  706 , thereby allowing flow through the opening  702 . The duckbill valve  720  has a pair of opposing flaps  722 , which open to form an opening in response to flow therethrough. The valve may be made of liquid silicone rubber (LSR). 
     An actuator portion  730  is applied to, or embedded into, the valve. For example, the actuator portion may be made of an electroactive polymer (EAP). When stimulated by an electric field, the LSR portion becomes stiffer, and resists opening. In one embodiment, the annular flange  704  of the valve is configured with a plurality of EAP strips  732  (shown as four). Other configurations, including more or less strips, or differently shaped portions, would also be suitable. In another embodiment, at least one of the flaps  722  of the duckbill valve  720 , and both flaps in one embodiment, are configured with an embedded electroactive polymer actuator portion  730 , for example a strip. It should be understood that the actuator portions, or EAP feature, may also be applied to the exhaust valve or exhalation portion  731  of the valves. 
     The VHC, or other medication delivery device, has a housing  2 ,  12  defining a flow channel  701 . The valve  700 ,  720  is disposed in the flow channel. The valve is moveable between first and second configurations, for example open and closed (completely or partially) in response to a flow through the flow channel. The flow may be inspiratory or expiratory. The valve is reconfigurable between a first condition and a second condition in response to a stimuli, for example an electrical stimuli. For example, the first and second conditions are first and second stiffnesses, or resistance to bending and/or deformation. The valve has a first resistance to moving between the first and second configurations, for example resistance to bending or deformation, when the valve is in the first condition, and the valve has a second resistance to moving between the first and second configurations when the valve is in the second condition, wherein the first resistance is greater than the second resistance. An actuator  708  applies the electrical stimuli. 
     In operation, a flow is created through the flow channel of the housing, for example by patient inhalation or exhalation. The flow causes the valve  700 ,  720  to move between first and second configurations in response to the flow through the flow channel. Depending on the flow rate calculated by various sensors and methods described herein in other sections of this disclosure, the actuator  708  may be instructed to apply a stimulus (e.g., electrical) to the valve as shown in  FIG. 34 . The valve is reconfigured from a first condition to a second condition in response to the stimulus. The flow through the channel is altered, for example restricted or increased, when the valve is reconfigured to the second condition, e.g., made more resistant to bending or deforming such that the opening formed by the valve, or between the valve and valve seat, is restricted or maintained smaller. 
     As shown in  FIG. 37 , the valve may be actively managed such that the flow rate through the valve, as sensed and detected as described above, does not exceed a predetermined threshold, e.g., 30 L/min. 
     In any of the above-described embodiments of smart devices, the controller or other processing element that communicates with or controls the sensors, gauges or switches may be integrated into, positioned on or in, or remotely located from the smart device itself. It should be understood that the various sensors, gauges or switches may serve multiple functions and may be used in various combinations, all in communication with the controller or other processing element. Additionally, for any of the smart devices described above, some or all of the data gathered and feedback provided to a user of the device by sensors, switches or gauges may simultaneously be transmitted to a remotely located caregiver. The remotely located caregiver or monitoring agency may intervene to provide further advice or information during a therapy session. Alternatively, the data and feedback transmitted to the caregiver or monitoring agency in parallel with the user may be stored remotely for later assessment by medical professionals. Concurrent transmission to a remote source of information, including the sensed data and any feedback, may also prevent problems with tampering or corruption of data stored on the smart device itself. 
     The battery or other power supply for any controller circuitry, sensors, gauges and switches may be rechargeable or removable in different embodiments of smart devices described herein. In order to minimize battery drain, certain of the sensors may be configured for a predetermined sampling frequency rather than a continuous measurement mode. Also, the circuitry on the smart device may only activate upon the detection of a particular event and may automatically turn off after a predetermined period from the initial trigger or after sensed idle period for the device. 
     Although the present invention has been described with reference to preferred embodiments. Those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. As such, it is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is the appended claims, including all equivalents thereof, which are intended to define the scope of the invention.