Effect on Physical Position of Peak Inspiratory Flow in Stable COPD: An Observational Study

Roy A Pleasants; Ashley G Henderson; Valentina Bayer; Asif Shaikh; M Bradley Drummond

doi:10.15326/jcopdf.2023.0460

Effect on Physical Position of Peak Inspiratory Flow in Stable COPD: An Observational Study

Chronic Obstr Pulm Dis. 2024 Mar 26;11(2):174-186. doi: 10.15326/jcopdf.2023.0460.

Authors

Roy A Pleasants^{1

2}, Ashley G Henderson³, Valentina Bayer⁴, Asif Shaikh⁴, M Bradley Drummond³

Affiliations

¹ Marsico Lung Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States.
² Division of Pulmonary and Critical Care Medicine, University of Michigan, Ann Arbor, Michigan, United States.
³ Division of Pulmonary Diseases and Critical Care Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States.
⁴ Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, Connecticut, United States.

PMID: 38236166
DOI: 10.15326/jcopdf.2023.0460

Abstract

Background: We examined the effect of physical position on peak inspiratory flow (PIF) in patients with chronic obstructive pulmonary disease (COPD) using dry-powder inhalers (DPIs) with low‑medium internal resistance (R2) and/or high internal resistance (R5).

Methods: This prospective study in stable, ambulatory patients with spirometry-confirmed COPD evaluated the effect of 3 physical positions on maximal PIF achieved. Participants had PIFs of 30-90L/min (R5) or 60-90L/min (R2 DPIs) using the In-Check™ DIAL. PIF was measured in triplicate randomly in 3 positions that patients might be in while using their inhaler (standing, sitting, and semi-upright [supine position with the head of the bed at 45°, neck flexed forward]) against prescribed DPI resistance (R2/R5/both). Correlations between PIF and percentage decline in PIF between positions and differences in participant characteristics with >10% versus ≤10% PIF decline standing to semi-upright were calculated.

Results: A total of 76 participants (mean age, 65.2 years) had positional measurements; 59% reported seated DPI use at home. The mean (standard deviation) PIF standing, sitting, and semi-upright was 80.7 (13.4), 77.8 (14.3), and 74.0 (14.5) L/min, respectively, for R2 and 51.1 (9.52), 48.6 (9.84), and 45.8 (7.69) L/min, respectively, for R5 DPIs. PIF semi-upright was significantly lower than sitting and standing (R2; P < 0.0001) and standing (R5; P= 0.002). Approximately half of the participants had >10% decline in PIF from standing to semi-upright. Patient characteristics exceeding the 0.10 absolute standardized difference threshold with the decline in PIF for both the R2 and R5 DPIs were waist-to-hip ratio, modified Medical Research Council dyspnea score, and postbronchodilator percentage predicted forced vital capacity and PIF by spirometry.

Conclusions: PIF was significantly affected by physical position regardless of DPI resistance. PIF was highest when standing and lowest when semi-upright. We recommend that patients with COPD stand while using an R2 or R5 DPI. Where unfeasible, the position should be sitting rather than semi-upright. ClinicalTrials.gov identifier NCT04168775.

Keywords: chronic airways obstruction; dry powder inhalers; inhalation technique; peak inspiratory flow rate.

Associated data

ClinicalTrials.gov/NCT04168775

Grants and funding

Boehringer Ingelheim Pharmaceuticals Inc/United States