Abstract
Forced mid-expiratory flow (i.e., isoFEF(25-75)) may increase with a short-acting β(2)-agonist in nonasthmatic children without bronchodilator responsiveness. This could also increase estimated ventilatory capacity along mid-expiration (V̇Ecap(25-75)), especially in vulnerable children with obesity who exhibit altered breathing mechanics. We estimated V̇Ecap(25-75) pre- and post-albuterol treatment in 8-12yo children without (n = 28) and with (n = 46) obesity. A two-way ANOVA was performed to determine effects of an inhaled bronchodilator (pre-post) and obesity (group) on isoFEF(25-75) and V̇Ecap(25-75). There was no group by bronchodilator interaction or main group effect on outcome variables. However, a significant main effect of the bronchodilator was detected in spirometry parameters, including a substantial increase in isoFEF(25-75) (17.1 ± 18.0 %) and only a slight (non-clinical) but significant increase in FEV(1) (2.4 ± 4.3 %). V̇Ecap(25-75) significantly increased with albuterol (+11.7 ± 10.6 L/min; +15.8 ± 13.9 %). These findings imply potentially important increases in ventilatory reserve with a bronchodilator in nonasthmatic children without and with obesity, which could potentially influence respiratory function at rest and during exercise.