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Prevalence and factors associated with suboptimal peak inspiratory flow rates in COPD

Authors Ghosh S, Pleasants RA, Ohar JA, Donohue JF, Drummond MB

Received 21 November 2018

Accepted for publication 31 January 2019

Published 1 March 2019 Volume 2019:14 Pages 585—595


Checked for plagiarism Yes

Review by Single-blind

Peer reviewer comments 2

Editor who approved publication: Dr Richard Russell

Sohini Ghosh,1 Roy A Pleasants,2 Jill A Ohar,3 James F Donohue,1 M Bradley Drummond1

1Division of Pulmonary Diseases and Critical Medicine, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; 2Durham VA Medical Center, Durham, NC, USA; 3Department of Medicine, Section of Pulmonary, Critical Care, Allergy, and Immunology, School of Medicine, Wake Forest University, Winston-Salem, NC, USA

Purpose: Adequate peak inspiratory flow rate (PIFR) is required for drug dispersion with dry powder inhalers (DPIs). Prevalence of PIFR discordance (suboptimal PIFR with prescribed inhalers) and factors influencing device-specific PIFR are unclear in COPD. The objective of this study was to determine the prevalence of PIFR discordance and associated clinical factors in a stable COPD population.
Patients and methods: An observational, single-center, cohort study was conducted including 66 outpatients with COPD. PIFR was measured using the In-Check™ Dial with applied resistance of prescribed inhalers. Participants were defined as discordant if measured PIFR was <30 L/min and <60 L/min for high and low–medium resistance devices, respectively, using an inspiratory effort the participant normally used with their prescribed DPI.
Results: The median age of the COPD participants was 69.4 years, 92% were white and 47% were female. A total of 48% were using low–medium resistance DPIs (Diskus®/Ellipta®) and 76% used high-resistance DPI (Handihaler®). A total of 40% of COPD participants were discordant to prescribed inhalers. Female gender was the only factor consistently associated with lower PIFR. Shorter height was associated with reduced PIFR for low–medium resistance (r=0.44; P=0.01), but not high resistance (r=0.20; P=0.16). There was no correlation between PIFR by In-Check™ dial and PIFR measured by standard spirometer.
Conclusion: PIFR is reduced in stable COPD patients, with female gender being the only factor consistently associated with reduced PIFR. Discordance with prescribed inhalers was seen in 40% of COPD patients, suggesting that many COPD patients do not generate adequate inspiratory force to overcome prescribed DPIs resistance in the course of normal use.

pulmonary disease, chronic obstructive, dry powder inhaler, peak inspiratory flow rate, drug delivery systems

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