Handling forces for the use of different inhaler devices.

Age and comorbidities can impact on the success of handling an inhaler. In this pilot study, we assessed finger strength in 62 participants (aged 5-17 years [n = 20], 18-65 years [n = 22] and > 65 years [n = 20]) by using different types of inhalers with integrated sensors (Respimat®, Breezhaler®, Aerolizer®, Genuair®, Diskus®, Ellipta®, HandiHaler®, Turbohaler® and a pressurized metered-dose inhaler [Atrovent®]). Parameters under investigation included the spontaneous and maximum achievable force and torque required to operate devices. Satisfaction with individual inhalers, and the relationship between satisfaction and strength, were also assessed. There was a marked difference in the compressive force required to operate individual inhalers, with maximum values ranging between 0.7 N and 39 N. Finger strength differed considerably between age groups, and participants with rheumatic disease showed different preferences and experienced more difficulties compared with healthy subjects. Satisfaction between devices was highly variable, and influenced by comorbidities and the ability to understand user instructions. Our findings suggest that individual patients' circumstances need to be considered when prescribing an inhaler and may help in the development of future devices, leading to design options with increased ease of operation.