Guideline for obtaining a chest X-ray in acute asthma exacerbation in children aged 6 to 18 years: assess the respiratory score; score 1 to 7, do not routinely obtain a chest X-ray, consider one after an inadequate response to 2 or more hours of treatment with any listed criterion; score 8 to 12, obtain a chest X-ray; exclusion criteria and other conditions where a chest X-ray is required are listed.