Purpose of Technology: The measurement of nitric oxide (NO) concentration in expired breath has been introduced as an adjunct to or replacement for established clinical and laboratory assessments of asthma control to guide the management of asthma. Measurement of fractional exhaled nitric oxide (FENO) is a noninvasive diagnostic technique. The NO molecules exhaled in breath can be measured using a handheld electrochemical sensor or a large, stationary chemiluminescence gas analyzer.

Controversy: NO, which is normally produced by the respiratory tract mucosa, is believed to be a powerful mediator involved in airway inflammation. The level of FENO could serve as a surrogate indicator or marker of airway inflammation, providing information to guide changes in asthma medications as the severity of asthma worsens or resolves. Asthma is a complex disease that has many potential contributing factors. Measurement of FENO may not be enough information to guide asthma therapy since it detects only 1 contributing factor. Furthermore, FENO may only be accurate for patients who have certain types of asthma.

Relevant Questions:

  • Does measurement of exhaled NO provide information that improves the management of asthma?

  • Is FENO measurement safe?

  • Which patients might be suitable candidates for guidance of asthma therapy based on FENO levels?

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