title: Peak inspiratory flow rate measurement by using In-Check DIAL for the different inhaler devices in elderly with obstructive airway diseases.
abstract: BACKGROUND
  Inhaler device technique is a common cause of treatment failure in patients with asthma and chronic obstructive pulmonary disease. Dry powder inhaler (DPI) requires optimal peak inspiratory flow rate (PIFR) for drug delivery. Low PIFR generation is common in the elderly. Patient lung function and intrinsic inhaler resistance are factors for determining generated PIFR and drug delivery from DPI.
  
  
  OBJECTIVE
  We aimed to identify the PIFR of the older (aged >60 years) and the younger (aged ≤60 years) patients with obstructive airway diseases for the different inhaler devices (Turbuhaler®and Accuhaler).
  
  
  METHODS
  A cross-sectional study was conducted from January to December 2014. Patients with obstructive airway diseases were recruited. Spirometry was performed. PIFR was measured by using an In-Check DIAL device. Individual PIFR values for each inhaler device were obtained for three consecutive measurements and then averaged.
  
  
  RESULTS
  A total of 139 patients diagnosed with obstructive lung diseases (asthma, n = 109; chronic obstructive pulmonary disease, n = 30) were recruited. Of these, 71 patients (51%) were >60 years. The PIFR generated by the patients who were ≤60 years for nonresistance mode was not different from that generated by those aged >60 years (115.0 ± 15.2 L/min vs 115.4 ± 13.3 L/min,p= 0.86). Regarding the DPI, PIFR generated from the older group was significantly lower than that generated from the younger group for Turbuhaler (72.5 ± 18.8 L/min vs 82.4 ± 21.1 L/min,p= 0.01), but the PIFR generated was not significantly different between the older and the younger groups for the Accuhaler (93.8 ± 22.9 L/min vs 99.4 ± 24.2 L/min,p= 0.86). The low peak expiratory flow rate and PIFR from spirometry were associated with the suboptimal PIFR measured by using In-Check DIAL.
  
  
  CONCLUSIONS
  Optimal PIFR is critical for DPI use in the elderly; appropriate DPI selection is essential for management. In-Check DIAL may be useful for detecting inhaler device problem among the elderly.
  
  
  CONCLUSIONS
  Lower PIFR generated from Turbuhaler was noted in patients with airway diseases who were older than 60 years, when compared to the younger patients.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Theerasuk
authors.initials: T
authors.lastname: Kawamatawong
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Supattra
authors.initials: S
authors.lastname: Khiawwan
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Prapaporn
authors.initials: P
authors.lastname: Pornsuriyasak
keywords: dry powder inhaler; elderly; obstructive airway diseases; peak inspiratory flow rate