Abstract
All DPIs are passive inhalers because they require the generation of an internal energy (P) from an interaction between the patient's inhalation and the device's resistance to deaggregate the formulation in the metered dose. During acute exacerbations patient inspiratory effort will be reduced and thus P will be reduced. We have measured the inhalation profiles of 18 asthmatics, mean(SD) age 42.0(11.8) years, on days 1-4 following their admission with an acute exacerbation. These measurements have been made using a Diskus (DKS), Easyhaler (EASY) and Turbuhaler (TBH) - inhalers with medium, medium/high and high resistance.
All parameters improved. PIF should not be considered in isolation and provides the wrong message, especially for high resistance DPIs, as PP and ACC are more important. The significance of the IV results needs to be investigated.
- © 2012 ERS