title: Input respiratory impedance in mice: comparison between the flow-based and the wavetube method to perform the forced oscillation technique.
abstract: Objective and approach: In this study, we estimated the constant phase model (CPM) parameters from the respiratory impedance of male BALB/c mice by performing the forced oscillation technique (FOT) in a control group (n  =  8) and in a murine model of asthma (OVA) (n  =  10). Then, we compared the results obtained by two different methods, using a commercial equipment (flexiVent-flexiWare 7.X; SCIREQ, Montreal, Canada) (FXV) and a wavetube method equipment (Sly et al 2003 J. Appl. Physiol. 94 1460-6) (WVT). We believe that the results from different methods may not be comparable. First, we compared the results performing a two-way analysis of variance (ANOVA) for the resistance, elastance and tissue damping.
  
  
  RESULTS
  We found statistically significant differences in all CPM parameters, except for resistance, when comparing Control and OVA groups. When comparing devices, we found statistically significant differences in resistance, while differences in elastance were not observed. For tissue damping, the results from WVT were observed to be higher than those from FXV. Finally, when comparing the relative variation between the CPM parameters of the Control and OVA groups in both devices, no significant differences were observed for all parameters.
  
  
  CONCLUSIONS
  We then conclude that this assessment can compensate the effect of using different cannulas. Furthermore, tissue damping differences between groups can be compensated, since bronchoconstrictors were not used. Therefore, we believe that relative variations in the results between groups can be a comparing parameter when using different equipment without bronchoconstrictor administration.
authors.affiliation: Biomedical Engineering Laboratory, Escola Politécnica, University of Sao Paulo, Av. Prof. Luciano Gualberto, travessa 3, nº 158, Predio Engenharia Elétrica, Room D2-01, ZIP 05508-900, Sao Paulo-SP, Brazil.
authors.forename: V
authors.initials: V
authors.lastname: Mori
authors.forename: M A
authors.initials: MA
authors.lastname: Oliveira
authors.forename: M H M
authors.initials: MHM
authors.lastname: Vargas
authors.forename: A A
authors.initials: AA
authors.lastname: da Cunha
authors.forename: R G
authors.initials: RG
authors.lastname: de Souza
authors.forename: P M
authors.initials: PM
authors.lastname: Pitrez
authors.forename: H T
authors.initials: HT
authors.lastname: Moriya
mesh_terms: D000818:Animals; D001249:Asthma / Q000503:physiopathology; D016085:Bronchoconstrictor Agents / Q000494:pharmacology; D017097:Electric Impedance; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008954:Models, Biological; D015656:Respiratory Mechanics / Q000187:drug effects; D012815:Signal Processing, Computer-Assisted
chemical_list: D016085:Bronchoconstrictor Agents