A New Quantitative Method for Evaluating Dry Powder Inhalation Efficiency in Asthma Patients

Many methods have been developed to evaluate dry powder inhalation techniques and their efficiency for disease control in asthma patients. However, it is difficult to apply these methods to clinical practice and research. In this study, we introduce a simple new method that can be applied to dry powder inhalation techniques to evaluate their efficiency in clinical practice. Twenty volunteers were recruited to evaluate the reliability of this new method. One hundred one asthma patients who met the inclusion criteria participated in this study. A dark cloth covered the outlet of the inhaler during dry powder inhalation. The image formed by the inhalation process was evaluated using analysis software and converted into integrated optical density (IOD). Inhalation techniques were scored before and after inhalation technique training, and asthma control was evaluated using the Asthma Control Questionnaire (ACQ) before inhalation technique training. The relative standard deviation of IOD ranged from 3.8% to 7.8%. In patients with or without inhaler prior use, both the IOD and inhalation technique scores improved significantly after inhalation technique training (p