title: Forced oscillations and respiratory system modeling in adults with cystic fibrosis.
abstract: BACKGROUND
  The Forced Oscillation Technique (FOT) has the potential to increase our knowledge about the biomechanical changes that occur in Cystic Fibrosis (CF). Thus, the aims of this study were to investigate changes in the resistive and reactive properties of the respiratory systems of adults with CF.
  
  
  METHODS
  The study was conducted in a group of 27 adults with CF over 18 years old and a control group of 23 healthy individuals, both of which were assessed by the FOT, plethysmography and spirometry. An equivalent electrical circuit model was also used to quantify biomechanical changes and to gain physiological insight.
  
  
  CONCLUSIONS
  The CF adults presented an increased total respiratory resistance (p < 0.0001), increased resistance curve slope (p<0.0006) and reduced dynamic compliance (p<0.0001). In close agreement with the physiology of CF, the model analysis showed increased peripheral resistance (p<0.0005) and reduced compliance (p < 0.0004) and inertance (p<0.005). Significant reasonable to good correlations were observed between the resistive parameters and spirometric and plethysmographic indexes. Similar associations were observed for the reactive parameters. Peripheral resistance, obtained by the model analysis, presented reasonable (R=0.35) to good (R=0.64) relationships with plethysmographic parameters.
  
  
  CONCLUSIONS
  The FOT adequately assessed the biomechanical changes associated with CF. The model used provides sensitive indicators of lung function and has the capacity to differentiate between obstructed and non-obstructed airway conditions. The FOT shows great potential for the clinical assessment of respiratory mechanics in adults with CF.
authors.affiliation: Pulmonary Function Laboratory - Faculty of Medical Sciences, State University of Rio de Janeiro, Rio de Janeiro, Brazil. adna.lima@yahoo.com.br.
authors.forename: Adma N
authors.initials: AN
authors.lastname: Lima
authors.affiliation: Biomedical Instrumentation Laboratory - Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Rio de Janeiro, Brazil. acdffisio@gmail.com.
authors.forename: Alvaro C D
authors.initials: AC
authors.lastname: Faria
authors.affiliation: Pulmonary Function Laboratory - Faculty of Medical Sciences, State University of Rio de Janeiro, Rio de Janeiro, Brazil. phel.lop@uol.com.br.
authors.forename: Agnaldo J
authors.initials: AJ
authors.lastname: Lopes
authors.affiliation: Pulmonary Function Laboratory - Faculty of Medical Sciences, State University of Rio de Janeiro, Rio de Janeiro, Brazil. jansen@centroin.com.br.
authors.forename: José M
authors.initials: JM
authors.lastname: Jansen
authors.affiliation: Biomedical Instrumentation Laboratory - Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Rio de Janeiro, Brazil. plopes@uerj.br.|BioVasc Research Laboratory - Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil. plopes@uerj.br.
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Melo
mesh_terms: D000328:Adult; D019121:Burkholderia Infections / Q000150:complications / Q000503:physiopathology; D057508:Burkholderia cenocepacia; D003198:Computer Simulation; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000150:complications / Q000503:physiopathology*; D017097:Electric Impedance; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008365:Manometry / Q000295:instrumentation / Q000379:methods*; D008954:Models, Biological; D010991:Plethysmography; D018410:Pneumonia, Bacterial / Q000150:complications / Q000503:physiopathology; D011552:Pseudomonas Infections / Q000150:complications / Q000503:physiopathology; D012123:Pulmonary Ventilation; D012129:Respiratory Function Tests / Q000295:instrumentation / Q000379:methods*; D015656:Respiratory Mechanics; D013147:Spirometry; D014160:Transducers, Pressure; D055815:Young Adult