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BACKGROUND: Inhaled corticosteroids are used to treat pediatric asthma. The shaking of a pressurized metered-dose inhaler (pMDI) is required to ensure consistency of emitted dose. Delays between shaking and actuating the pMDI are frequent during administration of aerosols to children where a valved holding chamber is used. METHODS: In a recent clinical trial, we used a monitoring device to record shaking and actuation of the pMDI and the inhalation profiles of children with asthma while they were inhaling fluticasone hydrofluoroalkane from a valved holding chamber onto an external filter. During the procedure, in vitro and transport samples were generated without a delay between shaking and actuating the pMDI. Emitted dose, expressed as percentage of ex-actuator nominal dose, obtained from the second actuation following a recorded shakeactuation interval for subjects and from in vitro/transport samples (no delay) were compared. RESULTS: The mean emitted dose was 158.6% (95% CI 150.1-167.2%) (subjects) and 106.8% (95% CI 104.7-108.9%) (in vitro + transport) of the ex-actuator nominal dose (P < .001). The mean delay between shaking and actuating the pMDI was 12.9 s (95% CI 11.9 -13.9 s) for the subject samples. A strong correlation was observed between shake and actuation delay and the emitted dose of the second actuation following the delay (Spearman correlation coefficient = 0.61). A 10-, 20-, and 30-s delay resulted in an emitted dose of the second actuation following the delay of 147, 187, and 227% of the ex-actuator nominal dose, respectively. CONCLUSIONS: Delays between shaking and actuating a corticosteroid suspension pMDI resulted in an increase in the emitted dose of the second actuation following the delay. This can be a common occurrence when doses are administered by a caregiver to a patient via a holding chamber. This should be addressed by practitioners educating patients and parents on proper inhaler use. (ClinicalTrials.gov registration NCT01714063.) [ABSTRACT FROM AUTHOR]

Anatomically accurate three-dimensional computer models of human lungs have been developed. In this work, the models are used as templates and superimposed on scintigraphy images from the medical arena. This protocol permits the composition of images to be determined and will thereby lead to improved risk assessment protocols for inhaled particulate matter. [ABSTRACT FROM AUTHOR]