Patient centric optimisation of a successful soft mist inhaler

Introduction: Since its introduction in 2004 Boehringer Ingelheim’s soft mist inhaler (Respimat) has been a user friendly inhaler. Patients and physicians appreciate the easy coordination and the high inhalable fraction. However, patients and physicians questioned why such a ‘high tech inhaler’ was not refillable. Aims: To develop a re-usable soft mist inhaler (re-usable Respimat) with improved usability, intended to be used with up to 6 cartridges. Methods: A comprehensive human factors engineering process was carried out: Two formative usability studies were conducted to evaluate general handling, instructions for use (IFU) and to compare the re-usable inhaler to the marketed device. Findings were considered in the design process. The usability confirmatory study of the final inhaler design, carried out in 3 countries, was a human factor study to confirm safe use. Results: Already in the first formative study, successful assembly and dose-administration was observed for all participants. As removal of the case lower part was evaluated to be difficult, the design was improved to enable easy removal. In addition, changes regarding dose counter design and IFU were considered focusing on cartridge-replacement. In the second formative study the re‑usable inhaler was compared to the current inhaler, and rated to be easier to assemble – in particular: Removal of case lower part and cartridge insertion. The new dose- and cartridge-counter were appreciated. The usability confirmatory study showed that the re-usable inhaler can be used safely and effectively with no harmful use errors. Conclusion: Implementing human factor engineering in the design process led to the development of a re-usable soft mist inhaler with improved usability.