The clinical significance of lung hypoexpansion in acute childhood asthma

Many children experiencing acute asthmatic episodes have chest radiographs, which may show lung hyperinflation, hypoinflation, or normal inflation. Lung hypoinflation may be a sign of respiratory fatigue and poor prognosis. To compare the clinical course in children with asthma according to the degree of lung inflation on chest radiographs. We conducted a retrospective study during a 24-month period (from July 1999 to July 2001) of children aged 0-17 years, who presented to a pediatric emergency department or outpatient clinic with an asthma exacerbation. Chest radiographs obtained at presentation were reviewed independently by three pediatric radiologists who were blinded to the admission status of the patient. The correlation between hypoinflation and hospital admission was assessed in three age groups: 0-2 years, 3-5 years, and 6-17 years. Hypoinflation on chest radiographs was significantly correlated with hospital admission for children aged 6-17 years (odds ratio 16.00, 95% confidence interval 1.89-135.43). The inter-reader agreement for interpretation of these radiographs was strong, with a kappa score of 0.76. Hypoinflation was not correlated with admission in younger children. Lung hypoinflation is associated with a greater likelihood of hospital admission in children aged 6 years or older. Therefore, hypoinflation was a poor prognostic sign and may warrant more aggressive therapy. (orig.)