Change in capnogram waveform is associated with bronchodilator response and asthma control in children.

Background: Airway hyper-reactivity, inflammation and remodeling contribute to inhomogeneity of ventilation-perfusion ratio in asthma. Short-term variations in can cause changes in expired capnographic indices.

Objectives: To measure acute changes in the phase 3 slope of the volumetric capnogram after β2-agonist inhalation (ΔSIII), for comparison with airway response based on FEV1 (ΔFEV1), and asthma control.