Quantitative End-Tidal Carbon Dioxide in Acute Exacerbations of Asthma

ObjectiveTo examine quantitative end-tidal carbon dioxide (ETCO2) in children with acute exacerbations of asthma. We hypothesize that quantitative ETCO2 will be lower in children during an acute exacerbation of asthma and will correlate with the severity of the exacerbation. We also hypothesize that ETCO2 can be successfully performed in all groups in the setting of a pediatric emergency department.Study designPatients with acute exacerbation of asthma (n = 86) and control subjects without respiratory or metabolic disturbances (n = 88) were prospectively enrolled in a pediatric emergency department. A physical examination, vital signs, and ETCO2 measurements were performed on arrival and, in the patients with asthma, after each bronchodilator treatment.ResultsETCO2 was measured successfully in 97% of enrolled children. After adjusting for respiratory rate, ETCO2 was significantly lower in patients with acute exacerbation of asthma than in control subjects (P < .001). ETCO2 measured after the first and after the final bronchodilator treatment were significantly associated with the number of bronchodilator treatments received and with hospital admission (P ≤ .002).ConclusionsETCO2 can be successfully measured in all children and is significantly lower in children with acute exacerbations of asthma compared with healthy control subjects. Quantitative ETCO2 may be an objective, noninvasive, and effort-independent way to assess the severity of asthma.