Prevalence and COPD phenotype for a suboptimal peak inspiratory flow rate against the simulated resistance of the Diskus® dry powder inhaler.

Abstract

Patients who exhibit a suboptimal peak inspiratory flow rate (PIFR) against the resistance (resist) of a dry powder inhaler (DPI) may not be able to effectively inhale the medication into their lower respiratory tract. PIFRresist was measured using the In-Check DIAL(®) to simulate the resistance of the Diskus(®) DPI in patients with chronic obstructive pulmonary disease (COPD) who were ≥ 60 years of age and had forced expiratory volume in 1 sec (FEV1) of ≤ 50% predicted. Our objectives were to: establish the prevalence of a suboptimal PIFRresist (< 60 L/min) in this population; identify a phenotype of patients with COPD who exhibit a suboptimal PIFRresist; and assess test-retest reliability of PIFRresist.