title: A New Quantitative Method for Evaluating Dry Powder Inhalation Efficiency in Asthma Patients.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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 < 0.05). Inhalation technique scores were positively correlated with IOD before (r = 0.80, p < 0.001) and after inhalation technique training (r = 0.52, p < 0.001). In patients with prior inhaler experience, ACQ results were negatively correlated with inhalation technique scores (r = -0.44; p < 0.05) and IOD (r = -0.52; p < 0.05).
  
  
  CONCLUSIONS
  The results from this study demonstrated that this quantitative method is equivalent to traditional methods for dry powder inhalation evaluation. This study also indicated that training significantly improved the inhalation technique and efficiency in asthma patients with or without prior inhaler use.
authors.affiliation: 1 Department of Family Medicine, West China Hospital, Sichuan University , Chengdu, China .
authors.forename: Yasha
authors.initials: Y
authors.lastname: Liang
authors.affiliation: 2 Department of Pulmonary Diseases, West China Hospital, Sichuan University , Chengdu, China .
authors.forename: Hefang
authors.initials: H
authors.lastname: Hu
authors.affiliation: 3 Department of Pulmonary Diseases, The People's Hospital of Henan province , Zhengzhou, China .
authors.forename: Cuijie
authors.initials: C
authors.lastname: Tian
authors.affiliation: 1 Department of Family Medicine, West China Hospital, Sichuan University , Chengdu, China .
authors.forename: Yi
authors.initials: Y
authors.lastname: Lei
authors.affiliation: 2 Department of Pulmonary Diseases, West China Hospital, Sichuan University , Chengdu, China .
authors.forename: Chuntao
authors.initials: C
authors.lastname: Liu
authors.affiliation: 2 Department of Pulmonary Diseases, West China Hospital, Sichuan University , Chengdu, China .
authors.forename: Fengming
authors.initials: F
authors.lastname: Luo
keywords: asthma; dry powder inhalation; quantitative evaluation