title: Validation of the Exhaled Breath Temperature Measure: Reference Values in Healthy Subjects.
abstract: BACKGROUND
  Exhaled breath temperature (EBT) is a new noninvasive method for the study of inflammatory respiratory diseases with a potential to reach clinical practice. However, few studies are available regarding the validation of this method, and they were mainly derived from small, pediatric populations; thus, the range of normal values is not well established. The aim of this study was to measure EBT values in an Italian population of 298 subjects (mean age, 45.2 ± 15.5 years; 143 male subjects; FEV1, 97.2% ± 5.8%; FVC, 98.4% ± 3.9%) selected from 867 adult volunteers to define reference values in healthy subjects and to analyze the influence of individual and external variables on this parameter.
  
  
  METHODS
  EBT was measured with an X-halo PRO device to different ambient temperature ranging from 0°C to 38°C.
  
  
  RESULTS
  We report reference values of EBT in healthy white subjects who had never smoked. EBT values were strongly influenced by the external temperature and to a lesser extent according to sex.
  
  
  CONCLUSIONS
  In a large population of healthy subjects who never smoked, these data provide reference values for measuring EBT as a basis for future studies. Our results are contribute to the promotion of EBT from "bench" to "bedside."
authors.affiliation: Department of Medical and Surgical Sciences, Institute of Respiratory Diseases, University of Foggia, Italy. Electronic address: giovannaelisiana.carpagnano@unifg.it.
authors.forename: Giovanna E
authors.initials: GE
authors.lastname: Carpagnano
authors.affiliation: Department of Medical and Surgical Sciences, Institute of Respiratory Diseases, University of Foggia, Italy.
authors.forename: Maria P
authors.initials: MP
authors.lastname: Foschino-Barbaro
authors.affiliation: Section of Statistics, Faculty of Economics, University of Foggia, Italy.
authors.forename: Corrado
authors.initials: C
authors.lastname: Crocetta
authors.affiliation: Department of Medical and Surgical Sciences, Institute of Respiratory Diseases, University of Foggia, Italy.
authors.forename: Donato
authors.initials: D
authors.lastname: Lacedonia
authors.affiliation: Department of Medical and Surgical Sciences, Institute of Respiratory Diseases, University of Foggia, Italy.
authors.forename: Valerio
authors.initials: V
authors.lastname: Saliani
authors.affiliation: Department of Medical and Surgical Sciences, Institute of Respiratory Diseases, University of Foggia, Italy.
authors.forename: Luigi Davide
authors.initials: LD
authors.lastname: Zoppo
authors.affiliation: Airway Disease Section, National Heart and Lung Institute, Imperial College London, Royal Brompton Hospital, London, UK.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Barnes
mesh_terms: D000328:Adult; D000368:Aged; D001944:Breath Tests / Q000379:methods*; D045853:Exhalation / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012129:Respiratory Function Tests; D013696:Temperature
keywords: airways inflammation; correction factor; exhaled breath temperature; noninvasive methods; reference value; validation