Clinical scenarios highlight utility of IOS. A, Three-year-old boy with food allergy, eczema, and chest symptoms; unable to perform spirometry. IOS indicates significant reversible obstruction. B, Eight-year-old boy with allergic rhinoconjunctivitis, dyspnea, and wheezing on examination. Normal spirometry but abnormal findings consistent with clinical presentation shown from IOS. C, Sixteen-year-old male adolescent with recurrent pneumothoraces unable to perform spirometry. Impulse oscillometry performed without event, showing normal lung function.