Abstract

Diagnosis
The diagnosis of EIB is established by changes in lung function provoked by exercise, not on the basis of symptoms. Serial lung function measurements after a specific exercise or hyperpnea challenge are used to determine if EIB is present and to quantify the severity of the disorder. It is preferable to assess FEV1, because this measurement has better repeatability and is more discriminating than peak expiratory flow rate. The airway response is expressed as the percent fall in FEV1 from the baseline value. The difference between the pre-exercise FEV1 value and the lowest FEV1 value recorded within 30 minutes after exercise is expressed as a percentage of the pre-exercise value. The criterion for the percent fall in FEV1 used to diagnose EIB is >10%. The severity of EIB can be graded as mild, moderate, or severe if the percent fall in FEV1 from the pre-exercise level is >10% but <25%, >25% but <50%, and >50%, respectively. A number of surrogates for exercise testing have been developed that may be easier to implement than exercise challenge. These surrogates include eucapnic voluntary hyperpnea or hyperventilation, hyperosmolar aerosols, including 4.5% saline, and dry powder mannitol.

Full Text

Comments