Issue link: http://www.e-digitaleditions.com/i/552614
nity for the prescribing clinician to personalize treatment to better meet the needs and aptitudes of the patient. 19 Yet this complexity can also increase confusion, both with respect to device selection as well as proper admin- istration of inhaled therapies. The degree of suitability of these devices for the older patient or caregiver by inhaler class is compared in Table 1. Several considerations have led to the choices made in Table 1: 1. Many older users cannot coordinate the onset of inhalation with actuation of a pMDI-based product; 4 the sudden hiss associated with propellant expansion may startle the patient to exhale instead of inhaling; 2. VHCs conserve the aerosol containing the medica- tion for several seconds after pMDI actuation; even if the patient exhales, the inhalation valve prevents exhaled air from entering the chamber and dispersing the aerosol; 20 3. VHCs and nebulizers can be supplied with a face- mask, as well as a mouthpiece, for use by the patient with limited manual dexterity and/or cognition; 4. DPIs, in general, require a significant inhalation effort to disperse the powder into an aerosol cloud having the optimum particle size distribution for deposition at receptors located at the airways of the lungs; 21 many older patents, especially those with emphysema associ- ated with severe COPD, may be incapable of such a maneuver; 10 5. The SMI is relatively simple to operate and delivers its medication as a low-velocity cloud (hence the name "soft mist inhaler"); 22 however, without a VHC used with the SMI to capture the mist, an older patient may still exhale at the critical moment, thereby dispersing the aerosol; 6. Though relatively slow delivery devices, nebulizers can provide the widest variety of treatment options 23 (though not triple combination therapy at the present time), and are readily set up in the home environment; cleaning and maintenance may, however, be a challenge, even with the electronic nebulization systems. 18 Regardless of the class of OIP prescribed, if patients are prescribed more than one different device type, it is important to note that the risk of failure to use both devices correctly increases. 24, 25 This result is likely caused by the increased difficulty experienced in remembering which operating procedures apply to which inhaler. Separate or in-built aids for the older patient A few stand-alone aids are already available to improve the ability of the older patient to achieve optimum ther- apy with pMDI, DPI and SMI products, where correct use demands more attention by the patient than when receiving therapy by nebulizer. For example, the Lever- Haler ® device (Birdsong Medical Inc., Cleveland, OH, US) provides additional mechanical advantage so that actuation of a press-and-breathe pMDI is made possible for the patient with limited finger and thumb move- ment in the hands. Add-on dose counters are also avail- able for use with pMDIs not having this feature already integral to the inhaler itself. There will likely always be a market for such aids, particularly those that cannot be readily incorporated into the inhaler design, or are useful for only a minority of the total patient population receiv- ing therapy via a particular inhaler device. However, in the context of assisting the older patient, the challenge to developers of future products is to inte- grate enabling features into existing products, so that they assist in both the process of preparing the inhaler for use, and subsequently actuating it correctly. An excellent example of this approach has been the development of the breath-actuated pMDI (for example, the Maxair™ Autohaler™, 3M Drug Delivery Systems, St. Paul, MN, US). This product illustrates how the need to provide mechanical effort in order to actuate the device is elimi- nated by virtue of building in technology that causes the inflow of air when the patient starts inhaling to trip an in-built mechanism, thereby triggering actuation of the pMDI. All the patient has to do beforehand is to move a small, clearly color-coded lever located on top of the device to the vertical "ready-to-actuate" position. The caregiver can also readily perform this task for a patient with severe hand movement and/or cognitive ability. The VHC is an example of an aid that by itself helps assure delivery of the fine particle component of the inhaled medication from press-and-breathe pMDIs, while retaining the coarser particulate that has no bene- ficial therapeutic value when it is delivered to the oropharynx, and which can result in adverse side effects with certain formulations (e.g., dysphonia and oral can- didiasis with ICS). 20 However, VHCs can be, and have been improved from the basic aerosol holding chamber 16 AuguSt 2015 Inhalation Table 1 The Major Classes of Inhalers for Oral Administration of Inhaled Formulations and Their Suitability for the Older Patient Inhaler Class pMDI alone pMDI + VHC DPI SMI Nebulizer Suitability for the older patient √ √√√ √ √√ √√√ Suitability via a caregiver √√ √√√ (with face- mask) √ √√ √√√ (with face- mask) √ = less suitable; √√ = suitable; √√√ = more suitable pMDI = pressurized metered dose inhaler VHC = valved holding chamber DPI = dry powder inhaler SMI = soft mist inhaler Nebulizer could be pneumatic jet/vibrating mesh/membrane/ultrasonic