An electronic nose in the discrimination of patients with asthma and controls

Dragonieri, Silvano; Schot, Robert; Mertens, Bart J.A.; Le Cessie, Saskia; Gauw, Stefanie A.; Spanevello, Antonio; Resta, Onofrio; Willard, Nico P.; Vink, Teunis J.; Rabe, Klaus F.; Bel, Elisabeth H.; Sterk, Peter J.

doi:10.1016/j.jaci.2007.05.043

« Previous Next »The Journal of Allergy and Clinical Immunology
Volume 120, Issue 4 , Pages 856-862, October 2007

An electronic nose in the discrimination of patients with asthma and controls

Silvano Dragonieri, MD
- Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Respiratory Diseases, University of Bari, Bari, Italy
Robert Schot, BEng
- Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands
Bart J.A. Mertens, PhD
- Department of Medical Statistics, Leiden University Medical Center, Leiden, The Netherlands
Saskia Le Cessie, PhD
- Department of Medical Statistics, Leiden University Medical Center, Leiden, The Netherlands
Stefanie A. Gauw, BN
- Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands
Antonio Spanevello, MD
- Department of Respiratory Diseases, Fondazione Maugeri, Cassano Murge, Italy
Onofrio Resta, MD
- Department of Respiratory Diseases, University of Bari, Bari, Italy
Nico P. Willard, PhD
- Philips Research, Eindhoven, The Netherlands
Teunis J. Vink, PhD
- Philips Research, Eindhoven, The Netherlands
Klaus F. Rabe, MD, PhD
- Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands
Elisabeth H. Bel, MD, PhD
- Department of Respiratory Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
Peter J. Sterk, MD, PhD
- Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Respiratory Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Reprint requests: Peter J. Sterk, MD, PhD, Department of Respiratory Diseases, F5-259, Academic Medical Center, University of Amsterdam, PO Box 22700, NL-1100 DE Leiden, The Netherlands.

Received 12 February 2007; received in revised form 24 May 2007; accepted 29 May 2007. published online 24 July 2007.

Background

Exhaled breath contains thousands of volatile organic compounds (VOCs) that could serve as biomarkers of lung disease. Electronic noses can distinguish VOC mixtures by pattern recognition.

Objective

We hypothesized that an electronic nose can discriminate exhaled air of patients with asthma from healthy controls, and between patients with different disease severities.

Methods

Ten young patients with mild asthma (25.1 ± 5.9 years; FEV₁, 99.9 ± 7.7% predicted), 10 young controls (26.8 ± 6.4 years; FEV₁, 101.9 ± 10.3), 10 older patients with severe asthma (49.5 ± 12.0 years; FEV₁, 62.3 ± 23.6), and 10 older controls (57.3 ± 7.1 years; FEV₁, 108.3 ± 14.7) joined a cross-sectional study with duplicate sampling of exhaled breath with an interval of 2 to 5 minutes. Subjects inspired VOC-filtered air by tidal breathing for 5 minutes, and a single expiratory vital capacity was collected into a Tedlar bag that was sampled by electronic nose (Cyranose 320) within 10 minutes. Smellprints were analyzed by linear discriminant analysis on principal component reduction. Cross-validation values (CVVs) were calculated.

Results

Smellprints of patients with mild asthma were fully separated from young controls (CVV, 100%; Mahalanobis distance [M-distance], 5.32), and patients with severe asthma could be distinguished from old controls (CVV, 90%; M-distance, 2.77). Patients with mild and severe asthma could be less well discriminated (CVV, 65%; M-distance, 1.23), whereas the 2 control groups were indistinguishable (CVV, 50%; M-distance, 1.56). The duplicate samples replicated these results.