A Comparison of Inhaler Devices and the Use of Inhalers in the Hospice Setting

 In COPD, Inhalers

A variety of new medications and combination treatments along with novel delivery devices are in development to help patients with COPD achieve improved symptom control and a better quality of life. This article will discuss different inhalation delivery devices currently available in the market (pMDI, DPI and Soft Mist Inhaler) and their limitations for hospice patients.

Types of inhalers

pMDI (pressurized metered dose inhaler) is the most commonly used device. The drug is dissolved in the propellant called hydrofluoroalkanes (HFAs) under pressure. The system releases a metered volume of propellant containing the medication. It requires a high degree of hand-breath coordination for effective treatment, which is the major disadvantage of pMDI. These devices deliver the medication at a high velocity which may result in some of the dose being deposited at the back of throat and swallowed instead of actually being inhaled, especially if the inhalation is not timed well with the actuation of the device.  Although a spacer or holding chamber may be used in conjunction with the inhaler to improve drug delivery in patients with poor coordination, this transforms the inhaler into a bulkier device that makes it less portable and more difficult to transport. Some examples of pMDI currently available in the market are Ventolin HFA, Xopenex HFA, Atrovent HFA, QVar, Flovent HFA, Advair HFA and Dulera.

DPI (dry powder inhaler) were developed to help overcome the problems of hand-breath coordination associated with pMDIs. The powdered drug is dispersed into particles by the patient’s own inspiratory effort. The issue of hand-breath coordination is resolved, but the patient must generate adequate inspiratory force to ensure that the medication from a DPI is being delivered to the lungs. This may result in erratic dosage and compromise the consistency in disease control for patients who have inadequate positive inhalation force.  Some examples of DPI currently available in the market are Foradil Aerolizer, Serevent Diskus, Adviar Diskus, Asmanex Twisthaler, and Breo Ellipta.

SMI (Soft Mist Inhaler) generates a soft mist that last longer and delivers higher fine particle fraction than the aerosol cloud, which should lead to improved lung and reduced oropharyngeal deposition versus other types of inhaler. Although the Soft Mist inhaler is not dependent on inspiratory flow rate and has simplified coordination of inhalation and actuation, the device still requires positive inhalation force and some degree of hand-breath synchronization.1 Currently Combivent Respimat, Striverdi Respimat, Spiriva Respimat and Stiolto Respimat are on the market.

Inhaler technique

Poor inhaler technique is often a main cause of sub-optimal COPD management. In a recent study of 1664 adult patients (mean age 62 years old), critical errors were observed in 12% of patients using a pMDI and 35% of patients using a DPI.2 According to the study, the most common critical errors with MDIs and DPIs are no or short breath-holding after inhalation and failure to achieve a forceful inspiratory flow, respectively. The correct inhalation technique of soft mist inhalers resembles that used with a MDI although the study did not assess the mishandling of SMI.

Use of inhalers in the hospice setting

In general, the use of inhaler devices may be limited in the hospice setting because most end-stage COPD patients do not have effective positive force to inhale medication contents from the device nor able to synchronize actuation with inhalation. Unlike the inhalers, no special inhalation techniques are needed for optimum delivery with conventional nebulizers, which is usually the most effective way to deliver inhaled medications in hospice patients. An inhaler should only be prescribed with the absolute certainty that the patient can use it correctly. Continued and repeated education for both healthcare professionals and patients in correct inhalation technique is essential to ensure optimal COPD management.

References

  1. Dalby R, Spallek M, Voshaar T. A review of the development of Respimat Soft Mist Inhaler. Int J Pharm 2004, 283:1-9.
  2. Melani AS, Bonavia M, Cilenti V, et al. Inhaler mishandling remains common in real life and is associated with reduced disease control. Respir Med 2011;105(6):
    930-8.

 

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