Effect of Nebulizer Breath-Guiding on Breathing Patterns and Lung Deposition

Background: Efficient aerosol therapy depends on both device performance and inhalation technique. Breath-triggered vibrating mesh nebulizers reduce drug loss by generating aerosol only during inspiration but may prolong treatment. Guiding patients toward slow, deep breathing could improve lung deposition and shorten nebulization time, yet quantitative evidence, particularly across disease groups, remains limited. Objective: To assess how integrated breath-guiding features influence breathing behavior, lung deposition, and user perception in healthy adults and in patients with obstructive or restrictive lung disease. Methods: Sixty-four participants inhaled through three nebulizer configurations: a low-resistance reference (eFlow OS) and two versions of the eFlow Integrated featuring direction-dependent resistance and multimodal feedback, tested with or without a breath-guiding app. Flow signals from multiple breaths were analyzed to determine phase-averaged breathing parameters. Device effects were evaluated by ANOVA. Representative breathing patterns and unsteady aerosol characteristics were input to a validated whole-lung in silico model to estimate deposition. User experience was assessed by questionnaire. Results: Breath-guiding consistently altered inhalation behavior. Peak inspiratory flow decreased by ∼20%, the I/E ratio increased by >15%, and with the breath guide app, tidal volume (+40%) and breath duration (+47%) increased. These effects were similar across disease groups. In silico simulations showed improved delivery with guided inhalation: lung drug deposition rate increased by 3.7% and 15.5%, and alveolar deposited mass fraction rose by 66% and 76% versus the reference. The breath guide app further shifted deposition from extrathoracic to thoracic and alveolar regions and reduced exhalation losses (–14%). Most participants (88%) were satisfied or very satisfied, citing pleasant resistance and helpful app guidance. Conclusion: Breath-guiding features and digital coaching reliably promote slower, deeper breathing, leading to greater lung and alveolar deposition and shorter expected nebulization times. High user acceptance underscores the clinical potential of patient-centric, guided inhalation in optimizing aerosol therapy.