Nitric Oxide Testing

Airway inflammation is the key

Asthma is caused by airway inflammation. This inflammation is caused by allergies, infections and irritants (such as smoke, pollution, chemicals etc.), otherwise known as asthma triggers. The inflammation results in swelling and excess mucus production in the airways. This causes bronchoconstriction or tightening of the airways and symptoms of asthma- cough, wheeze, difficulty breathing, chest tightness, etc. In asthma, the airway inflammation is present at all times even if there are no symptoms.

If inflammation is left untreated for several years, it leads to airway remodelling- a process similar to scarring but not identical with it. The airway destruction becomes permanent and can not be reversed. According to one estimate, a patient with uncontrolled asthma loses 3% of lung function (about 15 ml of lung volume) every year. Airway inflammation is the key element to be controlled if we want success from treating asthma. Therefore, inhaled steroids and not albuterol effectively reduce airway inflammation!

Measuring airway inflammation

Until now there were no widely available tests to measure airway inflammation. Office-based lung function tests measure airway obstruction and not inflammation. The FDA has recently approved an office-based test system to measure airway inflammation in people (adults and children who are 7 years old and above) with asthma. It is easy to use, relatively inexpensive, noninvasive and and the results are quickly obtained.

It is easy to do

The patient exhales and empties his or her lungs completely. Then he or she breathes in through a special disposable filter attached to the device and then breathes out in the same way without removing the device from mouth. The device gives audible clues to indicate if the patient is doing the procedure correctly. At the end of exhalation the device shows how much Nitric Oxide (FENO) is present in the patient's exhaled breath. The amount of Nitric Oxide present in the patient's exhaled breath is directly related to the amount of inflammation in the lungs. By measuring the amount of Nitric Oxide in the exhaled breath, it is possible to predict how much inflammation is present. The test should not take more than 5-10 minutes to perform.

Potential uses of the system

Nitrous Oxide measurement Inhaled steroids are used to treat airway inflammation in asthma. Now with the availability of Nitric Oxide measurement, steroid doses can be adjusted up or down according to individual patient's needs. Following levels of FENO can significantly reduce maintenance doses of inhaled steroids without compromising asthma control.

Measurement of FENO levels makes it also possible to tell if the patient is compliant with prescribed asthma medications. Elevated FENO levels in patients on maintenance doses of inhaled corticosteroids means either they are not taking their medication or that they are on too low a dose.

Rapidly increasing FENO levels (60% from baseline) could indicate that a major asthma exacerbation is about to happen and this gives both patients and doctors enough time to prevent this from happening.

Nitric Oxide measurement in combination with office-based lung function tests, improves the management and treatment of asthma. Call us to schedule an appointment ((650) 556-9577).