Title: Inhalation Parameters In Patients With Asthma Using Albuterol Electronic Multi-dose Dry Powder Inhaler
Abstract: Inhalation therapy is the mainstay of asthma treatment and reliant upon proper technique to allow optimal deposition of medication. Despite face-to-face demonstration of inhaler technique, patients do not maintain correct technique at home and errors are common. ProAir Digihaler (albuterol 90 μg/dose) is an electronic multi-dose dry powder inhaler designed with an integrated electronic module, which records objective information on inhaler usage and inhalation parameters, and thereby technique. This 12-week, open-label study assessed inhalation parameter changes in patients ≥18 years old with exacerbation-prone asthma. For rescue therapy, patients used Digihaler (1–2 inhalations every 4 hours) as needed, passively recording albuterol use and inhalation parameters (peak inspiratory flow [PIF], inhalation volume, and inhalation duration). We describe clinically relevant patterns based on Digihaler usage. Patients with ≥1 valid inhalation (n=360) from Digihaler were included in the analysis. Inhalation parameters varied both over the duration of the study, and during a single day. Most patients generated the minimum PIF threshold of 30 L/min all the time, regardless of exacerbation. Some patients showed expectedly consistent patterns in inhalation parameters preceding a clinical asthma exacerbation (CAE; increased inhaled dose, decreased PIF and inhalation volume). On average, both exacerbators and non-exacerbators displayed a gradual decrease in inhalation volume and duration during the study period. Inhalation parameters recorded by Digihaler may indicate inhaler technique deterioration or changes in underlying lung physiology preceding a CAE, and could help identify patients at risk of CAEs who might benefit from further instruction or intervention, potentially supporting improved asthma management.