Mannitol as an indirect bronchoprovocation test for the 21st century

To review mannitol challenge data and advocate the approval of this testing modality in the United States.

A literature review was performed using the MEDLINE database for English-language articles published between January 1, 1993, and July 31, 2009, using the following keywords: mannitol bronchoprovocation test, inhaled mannitol, inhaled mannitol and asthma, and inhaled mannitol and exercise-induced asthma.

Trials were selected that established the effect of mannitol as a bronchoprovocation challenge, explored mannitol's mechanism of action, and compared mannitol to other accepted bronchoprovocation challenges.

Mannitol has demonstrated the ability to detect airway hyperreactivity in individuals. The mechanism of action is through the release of mast cell mediators. The sensitivity and specificity compare well with other indirect challenge testing methods.

Mannitol is a polyol sugar that can be converted to a powdered form and encapsulated. Once encapsulated it can be inhaled and causes narrowing of the airways in susceptible individuals. Mannitol likely triggers the release of inflammatory and/or bronchospasm mediators, causing the smooth muscle of the airway to contract and resulting in airway narrowing. The magnitude of decrease in forced expiratory volume in 1 second and the dose of mannitol needed to provoke the airway response provide a readily measurable and clinically useful assessment of airway hyperreactivity. Mannitol challenge is an accepted testing method in Australia, Europe, and Korea. Acceptance of the mannitol challenge in the United States would complement existing methods for assessing bronchial hyperreactivity and likely improve patient care.