title: Usefulness of the Exhaled Breath Temperature Plateau in Asthma Patients.
abstract: BACKGROUND
  Exhaled breath temperature (EBT) has recently been proposed as a noninvasive marker of bronchial inflammation in patients with asthma. However, the usefulness of EBT in everyday clinical practice is not well established. Results to date are contradictory and are mainly derived from small, pediatric populations. A comparison of results is further complicated by the use of different equipment and measurements.
  
  
  OBJECTIVE
  We performed a comprehensive study to determine whether EBT is related to asthma control, disease severity, bronchial obstruction, or bronchial inflammation.
  
  
  METHODS
  Sixty-nine patients on maintenance treatment for asthma were included in a cross-sectional study. At the same visit, we measured the EBT plateau (EBTp) using an X-halo Breath Thermometer (Delmedica, Singapore), the fraction of exhaled nitric oxide (FeNO), spirometry, and inflammatory cell count in induced sputum, and we administered the Asthma Control Test questionnaire.
  
  
  RESULTS
  No significant differences were found between EBTp measurements and the level of asthma control, disease severity, bronchial obstruction, FeNO levels, or inflammatory asthma phenotypes. We found a significant difference between EBTp and gender. The EBTp was 34.07°C (SD 0.74) in women and 34.38°C (0.46) in men (p = 0.038). We also found a significant correlation between EBTp measurements and the induced sputum eosinophil count (R = -0.348, p = 0.003).
  
  
  CONCLUSIONS
  The results of this study do not support the usefulness of the EBTp in asthma management in routine clinical practice. Further research using standardized methods is needed to determine the potential use of the EBTp measurement in asthma management.
authors.affiliation: Department of Respiratory Medicine, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomédica Sant Pau (IIB Sant Pau), Barcelona, Spain.
authors.forename: Astrid
authors.initials: A
authors.lastname: Crespo Lessmann
authors.forename: Jordi
authors.initials: J
authors.lastname: Giner
authors.forename: Alfons
authors.initials: A
authors.lastname: Torrego
authors.forename: Eder
authors.initials: E
authors.lastname: Mateus
authors.forename: Montserrat
authors.initials: M
authors.lastname: Torrejón
authors.forename: Alicia
authors.initials: A
authors.lastname: Belda
authors.forename: Vicente
authors.initials: V
authors.lastname: Plaza
mesh_terms: D000328:Adult; D000368:Aged; D001249:Asthma / Q000175:diagnosis / Q000503:physiopathology; D001944:Breath Tests / Q000379:methods*; D002452:Cell Count / Q000379:methods; D045853:Exhalation / Q000502:physiology*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide; D012720:Severity of Illness Index; D013030:Spain; D013147:Spirometry / Q000379:methods; D013183:Sputum; D013223:Statistics as Topic; D013696:Temperature; D022722:Thermogenesis / Q000502:physiology*
chemical_list: D009569:Nitric Oxide