Propeller Sensor (Propeller Health, Wisconsin, USA)
The Propeller sensor is compatible for use with a wide range of devices, including pMDIs, Diskus®, Ellipta®, Turbohaler®, Easyhaler®, Breezhaler® and Respimat®(29). As such, the Propeller sensors can be used for both preventer and reliever inhalers recording the date, time and location of actuation(30). The sensors record when the inhalers are opened and closed as a surrogate for drug delivery, but inhaler technique is not recorded. As well as monitoring use, electronic notifications can be enabled to alert patients and providers of omitted doses.
The sensor transmits information via Bluetooth to a paired smartphone application and securely uploads the data to remote servers. Email notifications or text message alerts notify individuals and physicians about a change in asthma control based on reliever use. By providing personalised feedback, individuals are enabled to action changes and reduce the risk of an exacerbation(30, 31). Global Positioning System (GPS) transmitted through a smartphone provides geospatial information with the potential to help patients and HCPs identify asthma triggers. For example, increased SABA use may occur in a certain location associated with high exposure to a particular aeroallergen. When exposed to the same set of triggers in the future, patients are warned of the risk of a possible exacerbation(32).
Propeller sensors have been used in several studies to monitor ICS adherence, including change in ICS use for patients with asthma and COPD during the first few months of the COVID-19 pandemic(33-35). In an adult population with uncontrolled asthma, an increase in the percentage of SABA-free days was demonstrated in the group that received reminders and feedback on ICS and SABA use compared to a control group without feedback. Adherence changed minimally in the intervention group, whereas a significant decrease was seen in the control group(36). This study also identified a positive response in younger participants and those with worse asthma control at baseline, a subset of patients who are likely to particularly benefit from EMDs(36). Finally, as well as improvements in adherence to ICS and SABA use, a recent study has additionally reported a reduction in asthma-related emergency department visits and hospitalisations with the Propeller sensor highlighting the benefits of EMDs to both the patient and healthcare systems(33).