In vitro-in vivo correlation of aerosol deposition before and after metered-dose inhaler coaching in healthy children

Although pressurized metered dose inhaler (pMDI) education is a routine part of childhood asthma management and encouraging 'optimal breathing patterns' (i.e. slowly, deeply, completely, and with a mouth seal on the mouthpiece) is an integral part of recommended pMDI education, there is currently no quantifiable way to determine if a child is inhaling their medication correctly or optimally through a valved holding chamber (VHC). The TipsHaler™ (tVHC) is a prototype VHC device that measures inspiratory time, flow, and volume without changing the properties of the medication aerosol. The measurements recorded by the tVHC can be downloaded and transferred to a spontaneous breathing lung model to simulate the inhalational patterns and also determine the deposition of inhaled aerosol mass with each pattern. We hypothesized that pediatric patients' inhalational patterns when using a pMDI would improve after active coaching via tVHC. This would increase the pulmonary deposition of inhaled aerosols in an model. To test this hypothesis, we conducted a single-site, prospective, pilot, pre-and-post intervention study paired with a bedside-to-bench experiment. Healthy, inhaler-naïve subjects used a placebo inhaler in conjunction with the tVHC before and after coaching and recorded inspiratory parameters. These recordings were then implemented into a spontaneous breathing lung model during albuterol MDI delivery, and pulmonary deposition of albuterol was quantified. In this pilot study, active coaching resulted in a statistically significant increase in inspiratory time ( = 8, = 0.0344, 95%CI: 0.082 to ∞). tVHC recorded inspiratory parameters obtained from patients were successfully implemented in the model, which demonstrated that both inspiratory time ( = 8, = 0.78, 0.001, 95%CI: 0.47-0.92) and volume ( = 8, = 0.58, 0.0186, 95%CI: 0.15-0.85) strongly correlate with pulmonary deposition of inhaled drugs.