Deposition of inhaled nanoparticles is reduced in subjects with COPD and correlates with the extent of emphysema: proof of concept for a novel diagnostic technique

• Published in: Clinical physiology and functional imaging Vol. 38; no. 6; pp. 1008 - 1014
• Main Authors: Aaltonen, H. L, Jakobsson, J. K, Diaz, S, Zackrisson, S, Piitulainen, E, Löndahl, J, Wollmer, P
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.11.2018
• Subjects: Aerosols; AiDA; Airspace; Alveoli; Breath tests; Carbon monoxide; Chronic obstructive pulmonary disease; Clinical Medicine; Computed tomography; COPD; Correlation; CT densitometry; Densitometers; Densitometry; Diagnostic systems; Emphysema; Inhalation; Klinisk medicin; Lung diseases; Lungmedicin och allergi; Medical and Health Sciences; Medicin och hälsovetenskap; Nanoparticles; Obstructive lung disease; Patients; Radiologi och bildbehandling; Radiology and Medical Imaging; Respiration; respiratory diagnostics; Respiratory Medicine and Allergy; Smoking; AiDA; CT densitometry; nanoparticles; respiratory diagnostics; COPD; emphysema
• ISSN: 1475-0961; 1475-097X; 1475-097X
• DOI: 10.1111/cpf.12517

Summary Background The diagnosis of chronic obstructive pulmonary disease (COPD) is often based on spirometry, which is not sensitive to early emphysema. We have recently described a method for assessing distal airspace dimensions by measuring recovery of nanoparticles in exhaled air after a single‐breath inhalation followed by breath‐hold. Recovery refers to the non‐deposited particle fraction. The aim of this study was to explore differences in the recovery of exhaled nanoparticles in subjects with COPD and never‐smoking controls. A secondary aim was to determine whether recovery correlates with the extent of emphysema. Method A total of 19 patients with COPD and 19 controls underwent three repeats of single‐breath nanoparticle inhalation followed by breath‐hold. Particle concentrations in the inhaled aerosol, and in an alveolar sample exhaled after breath‐hold, were measured to obtain recovery. Findings The patients with COPD had a significantly higher mean recovery than controls, 0·128 ± 0·063 versus 0·074 ± 0·058; P = 0·010. Also, recovery correlated significantly with computed tomography (CT) densitometry variables (P<0·01) and diffusing capacity for carbon monoxide (DL,CO; P = 0·002). Interpretation Higher recovery for emphysema patients, relative to controls, is explained by larger diffusion distances in enlarged distal airspaces. The nanoparticle inhalation method shows potential to be developed towards a tool to diagnose emphysema.