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Theerasuk Kawamatawong, Supattra Khiawwan, Prapaporn Pornsuriyasak Division of Pulmonary and Critical Care Medicine, Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand 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. Objectives: 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). Patients and 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. Discussion: 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. Conclusion: Lower PIFR generated from Turbuhaler was noted in patients with airway diseases who were older than 60 years, when compared to the younger patients. Keywords: elderly, obstructive airway diseases, peak inspiratory flow rate, dry powder inhaler

Background: Small airways dysfunction (SAD) is not uncommon in asthma without fixed airflow obstruction (FAO)., Objective: We aimed to determine if SAD in non-FAO asthma is different from FAO-asthma and COPD., Methods: Cases of obstructive airway diseases who underwent spirometry, plethysmography, and impulse oscillometry [resistance at 5 Hz (R5) and at 20 Hz (R20), peripheral resistance (R5-R20), and reactance area (AX)] were reviewed, and classified as; 1) COPD, 2) FAO-asthma, and 3) non-FAO asthma. FAO was defined as post-bronchodilator (post-BD) FEV1/ FVC < 0.7. SAD was considered if 1) RV/TLC ≥ 40%, or 2) post-BD R5-R20 ≥ 0.075 kPa.L-1s., Results: A total of 73 patients (22 COPD, 24 FAO-asthma, and 27 non-FAO asthma) were analyzed. RV/TLC ratio was higher in FAO-asthma and COPD (45 ± 5% and 42 ± 8%) than in non-FAO asthma (32 ± 8%), p < 0.001. Post-BD values of R5-R20 and AX (median; range) were higher in FAO-asthma (0.17; 0.08, 0.47, 13.24; 6.52, 82.11) than in non-FAO asthma (0.11; 0.03, 0.23, 8.63; 2.40, 22.02), p = 0.007 and p = 0.017, respectively. The prevalence of SAD among diagnosis group by RV/TLC criterion was different (95%, 59%, and 15% in FAO-asthma, COPD, and non-FAO asthma, p < 0.001), but those were not observed by R5-R20 criterion (95%, 68%, and 77%, p = 0.052)., Conclusions: SAD in non-FAO asthma was less prevalent than FAO-asthma and COPD.