New Test Helps Track Asthma Severity

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A machine that measures exhaled nitric oxide may help physicians assess asthma severity, helping them to better calculate the need for inhaled corticosteroid medication.

The amount of nitric oxide in exhaled air is a sign of asthma, and higher levels of nitric oxide indicate that the asthma is getting worse. In the study, the researchers evaluated 46 individuals with asthma using the exhaled nitric oxide test and compared them with a group of 48 patients whose asthma was examined using standard measurements (ie, peak flow testing).

All of the participants had been using inhaled corticosteroids. Using both tests, the researchers modified the dose of fluticasone until the optimum dose for controlling asthma was reached. Once achieved, the patients were followed for 12 months. The final average dose of fluticasone was 370 mcg for the nitric oxide group versus 641 mcg for the control group. The results of the study showed that the rates of asthma exacerbations were <1 per patient per year. The nitric oxide group, however, averaged 45% fewer exacerbations, compared with the control group. The researchers said that nitric oxide machines should be available within 3 years. (The findings were reported in the New England Journal of Medicine, May 26, 2005.)