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Assessment of airway function in young children with asthma: Comparison of spirometry, interrupter technique, and tidal flow by inductance plethsmography
Author(s) -
Black J.,
BaxterJones A.D.G.,
Gordon J.,
Findlay A.L.,
Helms P.J.
Publication year - 2004
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.20046
Subject(s) - spirometry , medicine , anesthesia , tidal volume , asthma , plethysmograph , ventilation (architecture) , pulmonary function testing , cardiology , respiratory system , physics , thermodynamics
The assessment of airway function in young children requires adaptation of techniques designed for adults and/or application of techniques that do not require complex respiratory maneuvers. We sought to assess two methods of measuring airway function: time to peak expiratory flows as a ratio of expiratory time (T PTEF /T E ), derived from respiratory inductance plethysmography, and total respiratory resistance by the interrupter technique (Rint), both obtained during quiet tidal breathing. Both techniques were referenced to FEV 1 and flow at 50% expired volume (FEF 50 ) from conventional spirometry in 30 children aged 4–8 years (median age, 6.9; range, 4.5–8.5 years) with a physician diagnosis of asthma and who were able to perform FEV 1 with a repeatability of at least 8%. T PTEF /T E and Rint were performed in random order followed by spirometry, in order to reduce the possible effects of pulmonary stretch on tidal breathing measures. Coefficients of variation (CV) and mean absolute change/baseline standard deviation were derived for each measurement. Baseline FEV 1 did not correlate significantly with T PTEF /T E (r = 0.025), but did correlate with Rint (r = 0.737, P < 0.001); respective relationships for change after bronchodilator were r = 0.09 (ns) and r = 0.64 ( P < 0.001). FEF 50 also correlated significantly with Rint (R = 0.769, P < 0.001) but not with T PTEF /T E . FEV 1 and FEF 50 both increased postbronchodilator, with respective mean changes of 11.4% and 28% ( P < 0.001), while Rint decreased by 24.3% ( P < 0.001). No significant changes were noted for T PTEF /T E . T PTEF /T E derived from inductance plethysmography does not detect mild airway obstruction or modest changes in airway caliber following bronchodilator in young children with asthma. The interrupter technique may have a role in assessing baseline airway function and response to therapy in children unable to perform reliable spirometry, and/or when the investigator wishes to avoid the possible influence of forced maneuvers on airway tone. Pediatr Pulmonol. 2004; 37:548–553. © 2004 Wiley‐Liss, Inc.