title: Specific airway resistance in children: panting or tidal breathing?
abstract: BACKGROUND
  The measurement of specific airway resistance during tidal breathing (sRaw(tb)) has gained popularity in children, but methodological concerns have been raised regarding the electronic compensation for the thermal artifact. The panting method (sRaw(p)) is efficient in minimizing the latter, but may be associated with a change in end expiratory lung volume if the effort is not properly balanced. The aim of the study was to compare sRaw(tb) with sRaw(p) in children.
  
  
  METHODS
  Fifty-five children aged 6.5-11.5 years were studied. sRaw(tb) was measured in a commercial plethysmograph. sRaw(p) was measured with a home made equipment that allowed breath by breath analysis (sRaw(p1)) as well as with the commercial body box (sRaw(p2)).
  
  
  RESULTS
  sRaw(tb) was significantly larger than either sRaw(p1) or sRaw(p2) (P < 0.0001). The mean (95% CI) difference sRaw(p1)  - sRaw(tb) was -0.374 (-0.835 to 0.088) kPa s. The difference between sRaw(p1) and sRaw(p2) was significant (P < 0.005) but not clinically relevant, and mean (95% CI) difference sRaw(p1) - sRaw(p2) was 0.115 (-0.094 to 0.324) kPa s. The breath by breath analysis showed small but significant increase in sRaw(p1) throughout the maneuver (P < 0.001), whatever the pattern of end expiratory level.
  
  
  CONCLUSIONS
  Tidal breathing is associated with an overestimation of sRaw compared with panting in children. Although the latter results in small increase throughout the panting maneuver, sRaw(p) is probably more trustful than sRaw(tb).
authors.affiliation: EA 3450-Laboratoire de Physiologie, Faculté de Médecine, Université Lorraine, Vandoeuvre, France.
authors.forename: Laurianne
authors.initials: L
authors.lastname: Coutier
authors.forename: Silvia
authors.initials: S
authors.lastname: Varechova
authors.forename: Bruno
authors.initials: B
authors.lastname: Demoulin
authors.forename: Claude
authors.initials: C
authors.lastname: Bonabel
authors.forename: Clotilde
authors.initials: C
authors.lastname: Roman-Amat
authors.forename: Thanh Le
authors.initials: TL
authors.lastname: Tuan
authors.forename: Iulia
authors.initials: I
authors.lastname: Ioan
authors.forename: Cyril
authors.initials: C
authors.lastname: Schweitzer
authors.forename: François
authors.initials: F
authors.lastname: Marchal
mesh_terms: D000403:Airway Resistance / Q000502:physiology*; D016477:Artifacts; D001249:Asthma / Q000175:diagnosis* / Q000503:physiopathology; D002648:Child; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D010993:Plethysmography, Whole Body / Q000379:methods*
keywords: asthma; body plethysmography; child; healthy; thermal artifact