Within-day and between-day repeatability of measurements with an electronic nose in patients with COPD

Abstract

Electronic noses (e-noses), artificial sensor systems generally consisting of chemical sensor arrays for the detection of volatile compound profiles, have potential applications in respiratory medicine. We assessed within-day and between-day repeatability of an e-nose made from 32 sensors in patients with stable chronic obstructive pulmonary disease (COPD). We also compared between-day repeatability of an e-nose, fraction of exhaled nitric oxide (FENO) and pulmonary function testing. Within-day and between-day repeatability for the e-nose was assessed in two breath samples collected 30 min and seven days apart, respectively. Repeatability was expressed as an intraclass correlation coefficient (ICC). All sensors had ICC above 0.5, a value that is considered acceptable for repeatability. Regarding within-day repeatability, ICC ranged from 0.75 to 0.84 (mean = 0.80 ± 0.004). Sensors 6 and 19 were the most reproducible sensors (both, ICC = 0.84). Regarding between-day repeatability, ICC ranged from 0.57 to 0.76 (mean = 0.68 ± 0.01). Sensor 19 was the most reproducible sensor (ICC = 0.76). Within-day e-nose repeatability was greater than between-day repeatability (P < 0.0001). Between-day repeatability of FENO (ICC = 0.91) and spirometry (ICC range = 0.94-0.98) was greater than that of e-nose (mean ICC = 0.68). In patients with stable COPD, the e-nose used in this study has acceptable within-day and between-day repeatability which varies between different sensors.

Protein profile of exhaled breath condensate determined by high resolution mass spectrometry

“…Its systematic application to EBC representative of normal or pathological states appears therefore very promising for future development that may provide a fully validated clinical diagnostic tool. Furthermore, combination of EBC proteomic analysis with EBC NMR spectroscopy and electronic noses, which have been reported to be reproducible techniques [47,48] might provide a more comprehensive breathomics approach.…”

Breath Analysis in Real Time by Mass Spectrometry in Chronic Obstructive Pulmonary Disease

“…As a result, in recent years, a number of techniques have been developed to analyze exhaled breath for investigating COPD among other lung diseases. These include the analysis of exhaled-breath condensate [5,6,7,8,9,10,11,12], exhaled particles [13] and volatile compounds [14,15,16,17,18,19,20]. Even trained dogs seem to be able to recognize the peculiar scent of COPD in exhaled breath [21].…”

Exhaled Breath Temperature in Asthmatics and Controls after Eucapnic Voluntary Hyperventilation and a Methacholine Challenge Test

“…Similar studies should be undertaken with the aim of assessing the effects of EVH and MCT on markers of inflammation in exhaled breath condensate, including metabolites [24,25], leukotriene B4 [26] and isoprostanes [27,28] in patients with asthma. Likewise, it would be worth studying the effects of these challenges on e-nose breathprints [29,30]. …”