Diagnostic value of semi-volatile organic compounds in exhaled breath condensate of asthma and chronic obstructive pulmonary disease patients

Abstract

Summary. Asthma and chronic obstructive pulmonary disease (COPD) can exhibit overlapping clinical features; therefore, diagnosis of these diseases can be difficult. Search of new biomarkers represents an active research field in modern respiratory medicine. The objective of this study was to investigate spectrum of semi-volatile organic compounds (SvOCs) in exhaled breath condensate (EBC) of healthy volunteers and patients with asthma and COPD and to assess the possibility for using these biomarkers in differential diagnosis of obstructive lung diseases. Seventy subjects participated in this cross-sectional study: 20 patients with exacerbation of COPD (age, 66.5 Ѓ} 8.5 years; FEV1, 57.3 Ѓ} 22.9 %pred), 20 patients with exacerbation of asthma (age, 50.2 Ѓ} 13.2 years; FEV1, 71.4 Ѓ} 20.7 %pred) and 30 healthy nonsmoking volunteers (age, 25.4 Ѓ} 9.6 years, FEV1, 98.4 Ѓ} 6.8 %pred). EBC was collected using ECoScreen equipment. Testing for SvOC of different polarity was conducted by gas chromatography/mass-spectrometry (GC / MS) method in EBC. The data collected were analyzed using an algorithm based on linear methods of pattern recognition theory. More than a hundred of SvOC in ultra-low concentrations were detected in EBC of the participants; 33 of SvOC were identified; 9 compounds (2.3-dihydro-1-H- inden-1-on, ethyl citrate, decanol-1.2-phenoxyethanol, etc.) had the highest informative value to differentiate the conditions. Mathematical analysis allowed distinguishing healthy volunteers from patients with asthma with reliability of 75 %, healthy subjects from COPD patients with reliability of 85 % and asthma patients from COPD patients with reliability of 83 %. In conclusion, we have developed a highly accurate GC-MS method to measure ultra-low concentrations of SvOC in EBC. This method can be used for diagnosis and differentiation of COPD and asthma.