E-nose discriminative ability within a highly homogeneous sample of respiratory diseases

Background: profiling the composition of the exhaled breath, i. e. the pattern of volatile organic compounds (VOCs), by e nose is a simple, non invasive, rapid and inexpensive procedure. The e nose has notable properties versus different respiratory diseases such as lung tumors, COPD and asthma but discriminative ability within a homogeneous sample of respiratory diseases has never been tested.Aim of this study was to verify to which extent OSA, obesity, and COPD can be distinguished through e nose technology. Our objective was to characterize VOCs patterns of these conditions and assess its discriminatory capacity.Methods: eighty (20 obese non OSAS,20 hypoxemic OSAS,20 non Hypoxemic OSAS and 20 non hypoxemic COPD) subjects were recruited. Fiftysix healthy controls were also included. Between groups breath prints comparisons were made and Discriminant Analysis (PLS-DA) performed to built a model able to predict the underlying respiratory condition.Results: electronic nose did not discriminate OSAS patients from others. On the opposite, e-nose identified COPD patients and was able to identify controls (100% correct classification rate). One by one group comparison yielded an optimal discrimination of OSA vs controls and COPD vs controls.Conclusions: the e-nose technology cannot, at the moment, qualify as a screening procedure due to its lack of accuracy in discriminating between homogeneous pathologic conditions sharing systemic and organ-specific features (OSAS, COPD, Hypoxemia, Obesity). On the other hand, results suggest that the proposed technology is worthy of further testing as for its classificatory and discriminatory properties versus people with specific condition, especially COPD.