Exhaled Nitric Oxide Levels Indicate Treatment Efficacy in Children
Posted Nov 23 2009 10:34pm
MIAMI BEACH -- Children younger than 7 can successfully use devices that measure exhaled nitric oxide and monitor how well some treatments are controlling their asthma, a researcher reported here.
The measurement of nitric oxide gives doctors the opportunity to determine how well certain medications are handling asthma-caused inflammation in the airways.
"Similar to inhaled and systemic steroids, the anti-inflammatory effects of nebulized budesonide inhalation suspension can be monitored by measuring exhaled nitric oxide," Miguel Lanz, MD, of the AAADRS Clinical Research Center in Coral Gables, Fla., noted at a poster presentation during the annual meeting of the American College of Allergy, Asthma & Immunology.
Lanz said that in a small pilot study of 15 children with a mean age of 5 years, he determined the following:
The effect of nebulized budesonide starts to occur within three days after initiation of treatment, as evidenced by the significant improvement in exhaled nitric oxide.
Cessation of budesonide therapy revealed a return to baseline exhaled nitric oxide levels.
The exhaled nitric oxide test is a quick, easy-to-perform, reproducible, and noninvasive marker of airway inflammation in young people with asthma.
Children younger than 7 years can perform the respiratory maneuvers necessary for nitric oxide measurements in research mode, but only with a large, nonportable NIOX device.
"These children are capable of working with the larger NIOX device -- which is about the size of a mini-refrigerator -- better than the newer football-sized instrument," Lanz added.
He said the portable device -- although potentially handheld -- requires too many operations for youngsters to perform easily. The larger testing machine, which would require children to come to the clinic, requires only that the child exhale in a tube, and the machine does the rest of the work.
To conduct the the study, researchers obtained parental consent for children 4 to 6 years old who had been diagnosed with asthma for more than a year, were on stable medication, and were able to operate the nitric oxide measuring device.
At baseline, the mean exhaled nitric oxide level for the children was 25 parts per billion, Lanz said.
After three days of treatment with nebulized budesonide at a dose of 0.5 mg/2cc once daily in the open label study, the exhaled nitric oxide had decreased to 18 ppb ( P <0.01) from baseline. By the end of the two-week trial, the exhaled nitric oxide level had fallen to 15 ppb ( P <0.001) from baseline.
After a washout period, the exhaled nitric oxide levels rose to 26 ppb, he said.
Mean forced expiratory volume in one second (FEV 1 ) improved from 85 to 96 ( P <0.05). Mean peak expiratory flow improved from 143 L/min to 162 ( P< 0.05). After the washout period, the FEV 1 and peak expiratory volume did not worsen, Lanz said.
Lanz said the study showed that the impact of nebulized budesonide on exhaled nitric oxide is similar to that of inhaled corticosteroids.
"This study is interesting in that we see we can make these measurements with young children," said Talal Nsouli, MD, director of the Watergate and Burke Allergy and Asthma Centers in Washington, D.C. He said that determining levels of exhaled nitric oxide "is one of the best ways of measuring inflammation."