title: Increased exhaled breath temperature in subjects with uncontrolled asthma.
abstract: BACKGROUND
  Increased vascularity of the airway mucosa in asthma potentially increases heat loss in the airways.
  
  
  OBJECTIVE
  To determine if the inflamed airways of subjects with uncontrolled asthma show increased exhaled breath temperature (EBT).
  
  
  METHODS
  In 100 patients with persistent asthma and 50 healthy volunteers, we measured lung function by post-bronchodilator forced spirometry, the asthma control test (ACT) and EBT.
  
  
  RESULTS
  Patients with asthma, of whom 49 (49%) were female, with a mean (± standard error of the mean) age of 44 (±17) years and a predicted forced expiratory volume in one second of 71% (±16), had a significantly increased EBT, particularly those with uncontrolled asthma (n = 50, ACT ≤ 19, EBT 34.9 ± 0.8°C), compared to patients with controlled asthma (n = 50, ACT ≥ 20, EBT 33.7 ± 0.8°C) and healthy volunteers (n = 50, EBT 33.2 ± 0.2°C, P < 0.001).
  
  
  CONCLUSIONS
  We observed a higher temperature on exhaled breath in subjects with uncontrolled asthma than in subjects with controlled asthma and healthy controls. The increase in exhaled breath temperature may be a proxy for a raised airway inflammatory state in asthma patients.
authors.affiliation: CENASMA Centro Médico, La Plata, Buenos Aires, Argentina. cenasma@gmail.com
authors.forename: G
authors.initials: G
authors.lastname: García
authors.forename: M
authors.initials: M
authors.lastname: Bergna
authors.forename: E
authors.initials: E
authors.lastname: Uribe
authors.forename: A
authors.initials: A
authors.lastname: Yañez
authors.forename: J B
authors.initials: JB
authors.lastname: Soriano
mesh_terms: D000328:Adult; D001249:Asthma / Q000503:physiopathology*; D001831:Body Temperature; D001944:Breath Tests / Q000379:methods; D001993:Bronchodilator Agents / Q000494:pharmacology; D016022:Case-Control Studies; D045853:Exhalation; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007249:Inflammation / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D020545:Respiratory Mucosa / Q000098:blood supply / Q000473:pathology*; D013147:Spirometry; D055815:Young Adult
chemical_list: D001993:Bronchodilator Agents