Get Control of Your Asthma

Small airways linked to asthma control effectiveness

(RxWiki News) Controlling asthma and asthma symptoms has been the focal point of doctors and patients alike. Researchers are looking at the small-airways of the lungs to better control asthma.

Researchers are looking into small-airways function in the lungs as a way to determine asthma treatment effectiveness. Small-airway diseases, such as Chronic Obstructive Pulmonary Disease (COPD), feature similar symptoms and treatments, such as reduced lung function and inhaled corticosteroids, as asthma.

Understanding small-airways function can lead to better asthma control.

"Ask your doctor about ways to control your asthma."

The research involved 105 adult asthma patients and was led by Claude S. Farrah, M.B.B.S., from the Sydney Medical School at the University of Sydney in Australia. Researchers believed ventilation heterogeneity, or irregular airflow in the lungs, which causes airway hyperresponsiveness (AHR), may be used to understand asthma control.

Monitoring ventilation heterogeneity and small-airways function can help doctors better manage asthma symptoms.

Ventilation heterogeneity, much like asthma, responds to inhaled corticosteroids and bronchodilators. AHR, which is predicted by ventilation heterogeneity, occurs when airways in the lungs constrict significantly as a response to an irritant. This can lead to reduced lung function or coughing. Using an inhaled corticosteroid or bronchodilator will improve AHR and ease the narrowing of the airways.

The 105 asthma patients had lung function and asthma control, using a questionnaire, measured at the start of the study. Of the 105 patients, there was a subgroup of patients who suffered from AHR. This subgroup was given a high-dose inhaled corticosteroid treatment for three months.

Patients who had poorly-controlled asthma had low Forced Expiratory Volume (FEV) scores. FEV is a test that measure lung function by having a patient exhale for one second. A multiple-breath nitrogen washout technique, which measures how long it takes for a gas that is introduced into the lungs, in this case nitrogen, to leave the lungs, was also used.

The AHR subgroup, that was treated with inhaled corticosteroids, had significant improvements in the lung function tests. Asthma control for the AHR subgroup was also improved when compared to the poorly-controlled asthma group.

Asthma control is linked to predictors of small-airways disease, concludes researchers. Ventilation heterogeneity was improved with anti-inflammatory treatments which also improve asthma symptoms.

Measuring small-airway function can be a useful tool for doctors to monitor asthma treatment effectiveness. Future studies can examine specific ways of monitoring small-airway response to asthma treatment which can determine how effective the small-airways can be when it comes to predicting asthma control. 

No funding information was published. No author conflicts were reported.

This study was published in the February edition of The Journal of Allergy and Clinical Immunology.

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Review Date: 
February 13, 2012