title: Exhaled nitric oxide as a diagnostic tool for wheezing in preschool children: A diagnostic accuracy study.
abstract: BACKGROUND
  Airways inflammation may precede pulmonary dysfunction in wheezing individuals. The fraction of exhaled nitric oxide (FENO) has been described as a useful method for wheezing diagnosis in children, however, its application requires evidence. This study aimed to determine the accuracy of FENO in identifying wheezing in preschoolers.
  
  
  METHODS
  A cross-sectional study was carried out with children from 3 to 5 years old, from Brazilian day care centers and public schools. They were evaluated by FENO measurement through the single breath method, and by ATS-DLD-78-C questionnaire that is used as a gold standard to phenotype wheezing patterns.
  
  
  RESULTS
  The sample consisted of 243 non-wheezing children, 118 non-recurrent wheezing and 62 recurrent wheezing. The means of FENO and confidence intervals of 95%, were 5.4 (CI 95%, 5.2-5.6); 7.5 (CI 95%, 6.9-8.2) and 11.2 (CI 95%, 9.6-12.7), respectively. The sensitivity, specificity, positive and negative predictive FENO values in the 6 parts per billion (ppb) cut-off point that best diagnosed wheezing of non-wheezing children, were: 65.5%, 84.3%, 75.6% and 76.7%, respectively, with an area under the curve (AUC) = 0.77. At 10 ppb, the best cut-off points for differentiating recurrent wheezing of non-recurrent wheezing were: 56.4%, 81.3%, 61.4%, 78.0%, respectively, with an AUC = 0.69. The post-test probability for each FENO cut-off points was increased by 33% for wheezing and 20% for recurrent wheezing diagnosis when associated with clinical examination.
  
  
  CONCLUSIONS
  FENO can provide a reliable and accurate method to discriminate the presence and type of wheezing in preschoolers with 92% of acceptable in this study population.
authors.affiliation: Department of Physiotherapy, Universidade Federal de Pernambuco, Recife, Brazil.
authors.forename: Larissa Bouwman
authors.initials: LB
authors.lastname: Sayão
authors.affiliation: Department of Pediatric Pneumology, Instituto de Medicina Integral Fernando Figueira - IMIP, Recife, Brazil.
authors.forename: Murilo Carlos Amorim
authors.initials: MC
authors.lastname: de Britto
authors.affiliation: Department of Pediatric Pneumology, Instituto de Medicina Integral Fernando Figueira - IMIP, Recife, Brazil.
authors.forename: Edjane
authors.initials: E
authors.lastname: Burity
authors.affiliation: Department of Physiotherapy, Universidade Federal de Pernambuco, Recife, Brazil.
authors.forename: Catarina
authors.initials: C
authors.lastname: Rattes
authors.affiliation: Department of Physiotherapy, Universidade Federal de Pernambuco, Recife, Brazil.
authors.forename: Cyda Maria Albuquerque
authors.initials: CM
authors.lastname: Reinaux
authors.affiliation: Rush University Medical Center, Georgia State University, USA.
authors.forename: James
authors.initials: J
authors.lastname: Fink
authors.affiliation: Department of Physiotherapy, Universidade Federal de Pernambuco, Recife, Brazil. Electronic address: armeledornelas@hotmail.com.
authors.forename: Armèle
authors.initials: A
authors.lastname: Dornelas de Andrade
mesh_terms: D001944:Breath Tests / Q000379:methods; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D000068598:Data Accuracy; D045853:Exhalation; D005260:Female; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012135:Respiratory Sounds / Q000175:diagnosis* / Q000503:physiopathology*
chemical_list: D009569:Nitric Oxide
keywords: Child; Nitric oxide; ROC curve; Respiratory sounds; Sensitivity and specificity