A Rapid, Handheld Device to Assess Respiratory Resistance: Clinical and Normative Evidence

Authors

Aaron B. Holley, San Antonio Military Medical CenterFollow
Wesley D. Boose, United States Naval Hospital, Guam
Michael Perkins, Southeast Lung Associates, Savannah, Georgia
Karen L. Sheikh, Respira Medical, Linthicum, Maryland
Nancy P. Solomon, Walter Reed National Military Medical CenterFollow
Angela M. Dietsch, University of Nebraska-LincolnFollow
Jafar Vossoughi, Engineering and Scientific Research Associates, College Park, Maryland
Arthur T. Johnson, University of MarylandFollow
Jacob F. Collen, Walter Reed National Military Medical CenterFollow

ORCID IDs

Dietsch 0000-0003-4554-5365

Document Type

Article

Date of this Version

2018

Citation

Military Medicine (2018)

doi: 10.1093/milmed/usx224

Comments

United States government work

Abstract

Introduction: Following reports of respiratory symptoms among service members returning from deployment to South West Asia (SWA), an expert panel recommended pre-deployment spirometry be used to assess disease burden. Unfortunately, testing with spirometry is high cost and time-consuming. The airflow perturbation device (APD) is a handheld monitor that rapidly measures respiratory resistance (APD-R_r) and has promising but limited clinical data. Its speed and portability make it ideally suited for large volume pre-deployment screening. We conducted a pilot study to assess APD performance characteristics and develop normative values.

Materials and Methods: We prospectively enrolled subjects and derived reference equations for the APD from those without respiratory symptoms, pulmonary disease, or tobacco exposure. APD testing was conducted by medical technicians who received a 10-min in-service on its use. A subset of subjects performed spirometry and impulse oscillometry (iOS), administered by trained respiratory therapists. APD measures were compared with spirometry and iOS.

Results: The total study population included 199 subjects (55.8% males, body mass index 27.7 ± 6.0 kg/m², age 49.9 ± 18.7 yr). Across the three APD trials, mean inspiratory (APD-R_i), expiratory (APD-R_e), and average (APD-R_avg) resistances were 3.30 ± 1.0, 3.69 ± 1.2, and 3.50 ± 1.1 cm H₂O/L/s. Reference equations were derived from 142 clinically normal volunteers. Height, weight, and body mass index were independently associated with APD-R_i, APD-R_e, and APD-R_avg and were combined with age and gender in linear regression models. APD-R_i, APD-R_e, and APD-R_avg were significantly inversely correlated with FEV₁ (r = −0.39 to −0.42), FVC (r = −0.37 to −0.40), and FEF_25–75 (r = −0.31 to −0.35) and positively correlated with R5 (r = 0.61–0.62), R20 (r = 0.50–0.52), X5 (r = −0.57 to −0.59), and FRES (r = 0.42–0.43). Bland–Altman plots showed that the APD-R_r closely approximates iOS when resistance is normal.

Conclusion: Rapid testing was achieved with minimal training required, and reference equations were constructed. APD-R_r correlated moderately with iOS and weakly with spirometry. More testing is required to determine whether the APD has value for pre- and post-deployment respiratory assessment.