BackgroundInhaled medications are commonly used as therapy for obstructive lung disease (OLD) yet poor technique from pressurized metered dose inhalers (pMDI) can severely limit drug delivery and therapeutic efficacy. A novel flow sensor has been developed to characterize inhalation flow profiles from pMDIs. Research QuestionAmong OLD subjects, flow profiles during pMDI inhalation maneuvers would expose poor patterns of pMDI use, which can be used to remediate pMDI technique. Study Design and MethodsA novel flow sensor was coupled to a placebo pMDI inhaler to characterize inhalation technique in 70 OLD participants from a pulmonary clinic. pMDI inhalation flow profiles generated actuation timing, mean inspiratory airflow (MIF) and inspired volume before and after visualizing these features. McNemar’s was used to characterize the impact of training on pMDI inhalation metrics. The post-actuation inspired volume was normalized to inspiratory capacity (IC). ResultsAmong participants with 17.4 (SD = 17.9) years of pMDI use, flow profiles uncovered mistimed actuations in 47.1% and poor inspiratory flow rates in 30.0% of subjects. After visualizing flow profiles, participants improved actuation timing (c2(1) =12.042, p < .001), mean inhaled volume (87.9 to 105.6% of IC, p<0.001) and the combined inhalation metrics (c2(1) =8.45, p = 0.003). InterpretationFlow profiles helped uncover and remediate specific defects in pMDI technique in the majority of chronic OLD users. Flow profiles from inhaled medications can be used to enhance drug delivery to the lung.
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