Primary Outcome Measures:
- The primary analysis variable will be the percent change in FENO measured with
- NIOX MINO® and NIOX® between Visit 1 to Visit 2.
Secondary Outcome Measures:
- Agreement between NIOX MINO® and NIOX® will be assessed by comparing
- individual pair-wise FENO measurements from visit V1.
- The change in FENO measured with NIOX MINO following corticosteroid therapy
- in asthma will be compared with improvements in standard asthma outcome
- measures (asthma symptoms and spirometry).
- To investigate the inter-operator variability FENO measurements with
- NIOX MINO in the same subject when different operators take FENO measurements. Three operator each takes two completed measurements in the same subject in a point of care setting.
Asthma is a chronic inflammatory disorder of the airways. Chronically inflamed airways are hyperresponsive; they become obstructed and airflow is limited (by bronchoconstriction, mucus plugs, and increased inflammation) when airways are exposed to various risk factors. Asthma causes recurring episodes of wheezing, breathlessness, chest tightness, and coughing particularly at night or in the early morning.
NO is an important endogenous regulatory molecule that is widely distributed throughout the body. The detection of NO in exhaled air was first reported in 1991, and, soon after it was shown that the levels NO in exhaled air are elevated in patients with asthma. There is now much evidence showing that measurement of the concentration of NO in exhaled air offers a useful non−invasive method of assessing inflammatory airway disease.
Exhaled NO is not increased during bronchospasm unless there is coexisting inflammation. Exhaled NO may have a valuable role in differentiating between the inflammatory and bronchospastic components of clinical asthma, and is also useful for guiding the therapeutic use of steroids and other anti−inflammatory agents.
A study on asthmatics and non−asthmatics subjects has shown that substantial equivalence exists between the stationary device NIOX® and the hand held device NIOX MINO® when comparing NO measurements, when similar conditions are considered and examinations are made as consistently as possible.
In a study with the stationary device NIOX®, exhaled NO was measured before and after two weeks of inhaled corticosteroid treatment in unstable steroid−naïve adult and paediatric asthmatic subjects. The result was a 50.5% mean reduction of exhaled NO. The change in exhaled NO was also compared to change in standard asthma outcome measures, asthma symptoms and spirometry.