title: Exhaled breath temperature, a new biomarker in asthma control: a pilot study.
abstract: OBJECTIVE
  To evaluate whether the exhaled breath temperature (EBT), measured by a noninvasive method, is an effective means of monitoring patients with uncontrolled asthma.
  
  
  METHODS
  A pilot study comprising nine patients (seven women and two men; mean age: 39 years) diagnosed with asthma at least one year prior to the beginning of the study and not having been under maintenance therapy for the last three months. In the first visit, the patients underwent spirometry and measurement of EBT. The patients were then instructed to use inhaled budesonide/formoterol (200/6 µg) every 12 h for six weeks. In addition, the patients with severe asthma (FEV1 < 60% of predicted) were instructed to use oral prednisolone (40 mg/day) for five days. After six weeks, the patients underwent the same tests.
  
  
  RESULTS
  All of the patients reported an improvement in the symptoms of asthma, as confirmed by a statistically significant increase in FEV1 from the first to the second visit (mean, 56.1% vs. 88.7% of predicted; p < 0.05). Five patients used oral prednisolone for the first five days of the treatment period. Six patients used additional doses of inhaled budesonide/formoterol (mean duration, 2.5 weeks). The EBT decreased significantly from the first to the second visit (mean EBT: 35.1 ºC vs. 34.1 ºC; p < 0.05).
  
  
  CONCLUSIONS
  Uncontrolled asthma, especially during exacerbations, is followed by an increase in EBT, which decreases after appropriate asthma control, as demonstrated by an increase in FEV1 and an improvement of the reported symptoms. These preliminary results suggest that EBT can be used as a parameter for the assessment of asthma control.
authors.affiliation: Departamento de Pediatria, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brasil. contato@raulmelo.com.br
authors.forename: Raul Emrich
authors.initials: RE
authors.lastname: Melo
authors.forename: Todor A
authors.initials: TA
authors.lastname: Popov
authors.forename: Dirceu
authors.initials: D
authors.lastname: Solé
mesh_terms: D000328:Adult; D000368:Aged; D001249:Asthma / Q000188:drug therapy* / Q000517:prevention & control; D001831:Body Temperature / Q000187:drug effects / Q000502:physiology*; D001944:Breath Tests / Q000295:instrumentation* / Q000379:methods; D001993:Bronchodilator Agents / Q000627:therapeutic use; D002648:Child; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects / Q000502:physiology; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects
chemical_list: D001993:Bronchodilator Agents; D005938:Glucocorticoids