Influence of circadian rhythm on exhaled breath profiling by electronic nose

J Biol Regul Homeost Agents. 2018 Sep-Oct;32(5):1261-1265.

Abstract

Electronic noses (e-noses) are a cheap and easy method for exhaled Volatile Organic Compound (VOC)-analysis which has shown its potential in several diseases. Before obtaining a full validation of these instruments in clinical settings, a number of methodological issues still have to be established. We aimed to investigate a potential influence of circadian variation on VOC-profile analyzed by an e-nose in healthy subjects. We enrolled 22 adults free of any known diseases. A sequence of exhaled breath samplings were performed on all participants at predetermined hours (7am, 12pm, 17pm, 23pm) and analyzed by an e-nose (Cyranose 320). According to Principal Component Analysis, significant circadian variations of the exhaled VOC-profile were shown for Principal Component (PC) 1 and 3. In detail, PC1 and PC3 values were significantly higher in the morning compared to the afternoon and evening (for all parameters p less than 0.05). Successive Linear Discriminant analysis confirmed the findings above. The daily variations in VOCs-profile, with the peak in the morning, could be relevant for future clinical applications, especially in the choice of optimal time for sampling patients.

Publication types

  • Letter

MeSH terms

  • Adult
  • Breath Tests*
  • Circadian Rhythm / physiology*
  • Discriminant Analysis
  • Electronic Nose*
  • Exhalation / physiology*
  • Humans
  • Linear Models
  • Principal Component Analysis
  • Time Factors
  • Volatile Organic Compounds / analysis

Substances

  • Volatile Organic Compounds