Nitric Oxide as a Clinical Guide for Asthma Management
Nitric Oxide as a Clinical Guide for Asthma Management
Taylor DR
J Allergy Clin Immunol. 2006;117:259-262
The treatment of asthma has undergone a number of evolutions over the last several decades. Asthma was at one time thought to be primarily a bronchospastic disease, and therefore needed to be treated with bronchodilators. We then learned that much of the bronchospasm present in asthma was in fact the result of inflammation in the airways, and that its effective treatment had to address the inflammation. The combination of inhaled corticosteroids and bronchodilators proved to be much more effective than bronchodilators alone. With time, it became clear that various patients responded differently to the same type of medical treatment, with some, for example, requiring higher doses of inhaled corticosteroids.
When addressing the issue of individualization of inhaled corticosteroid dosing, a number of methods can be used. The National Institute of Health/National Asthma Education and Prevention Program (NIH/NAEPP) guidelines suggest the use of both subjective measures (ie, asthma symptoms) and objective measures (ie, spirometry values) to classify disease severity. The classification is then used to decide on an appropriate course of therapy. Recent evidence has suggested that the airway inflammation in asthma is mostly attributable to eosinophils and that the fraction of exhaled nitric oxide (FeNO) reflects the level of eosinophilic inflammation; FeNO may be used to guide the dose of inhaled steroids using this real-time measure of eosinophilic inflammation.
In this article, Dr. Taylor notes that asthma is a heterogeneous disease, with some patients having more eosinophilic inflammation than others. Since eosinophilic inflammation is usually responsive to inhaled corticosteroids (ICS), measurement of FeNO has allowed cost-effective dosage modification of ICS in patients with asthma. FeNO measurements are now being shown to be a potentially helpful tool in management of patients with asthma, although their routine clinical utility is still being investigated and reference values and important cut-points are still being determined.
It is important for the clinician caring for patients with asthma to be aware that this technology may play an important role in steroid dosing decisions in the future. As the cost of FeNO measurement falls, this tool may be more widely used to help determine the degree of eosinophilic inflammation in the asthmatic airway. Once the degree of inflammation can be better quantified, medication dosing decisions (eg, inhaled corticosteroid dosing) will be more accurately accomplished.
Abstract
Taylor DR
J Allergy Clin Immunol. 2006;117:259-262
The treatment of asthma has undergone a number of evolutions over the last several decades. Asthma was at one time thought to be primarily a bronchospastic disease, and therefore needed to be treated with bronchodilators. We then learned that much of the bronchospasm present in asthma was in fact the result of inflammation in the airways, and that its effective treatment had to address the inflammation. The combination of inhaled corticosteroids and bronchodilators proved to be much more effective than bronchodilators alone. With time, it became clear that various patients responded differently to the same type of medical treatment, with some, for example, requiring higher doses of inhaled corticosteroids.
When addressing the issue of individualization of inhaled corticosteroid dosing, a number of methods can be used. The National Institute of Health/National Asthma Education and Prevention Program (NIH/NAEPP) guidelines suggest the use of both subjective measures (ie, asthma symptoms) and objective measures (ie, spirometry values) to classify disease severity. The classification is then used to decide on an appropriate course of therapy. Recent evidence has suggested that the airway inflammation in asthma is mostly attributable to eosinophils and that the fraction of exhaled nitric oxide (FeNO) reflects the level of eosinophilic inflammation; FeNO may be used to guide the dose of inhaled steroids using this real-time measure of eosinophilic inflammation.
In this article, Dr. Taylor notes that asthma is a heterogeneous disease, with some patients having more eosinophilic inflammation than others. Since eosinophilic inflammation is usually responsive to inhaled corticosteroids (ICS), measurement of FeNO has allowed cost-effective dosage modification of ICS in patients with asthma. FeNO measurements are now being shown to be a potentially helpful tool in management of patients with asthma, although their routine clinical utility is still being investigated and reference values and important cut-points are still being determined.
It is important for the clinician caring for patients with asthma to be aware that this technology may play an important role in steroid dosing decisions in the future. As the cost of FeNO measurement falls, this tool may be more widely used to help determine the degree of eosinophilic inflammation in the asthmatic airway. Once the degree of inflammation can be better quantified, medication dosing decisions (eg, inhaled corticosteroid dosing) will be more accurately accomplished.
Abstract
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