Measuring fractional exhaled nitric oxide concentration in asthma: NIOX MINO, NIOX VERO and NObreath

4.1 NIOX MINO (Aerocrine) is a diagnostic and monitoring device that analyses a breath sample using an electrochemical sensor to determine exhaled nitric oxide concentration. The technology is designed to help identify people whose airway inflammation is likely to respond to treatment with inhaled corticosteroids. It can also help to predict the onset of asthma symptoms or loss of asthma control, and to monitor compliance with corticosteroid therapy and the effectiveness of treatment.

4.2 NIOX MINO determines exhaled nitric oxide concentration in a breath sample. The device is small, hand-held and portable, and can be used by adults and children. It needs a 10-second exhalation of breath at a pressure of 10–20 cm H₂O to maintain a fixed flow rate of 50±5 ml/s. The last 3 seconds of the 10-second exhalation are analysed by a calibrated electrochemical sensor to give a definitive result in parts per billion. Clinical cut-off values can be applied to the exhaled nitric oxide values to categorise readings as low, intermediate or high according to the reference ranges for ages less than 12 years and 12 years or more.

4.3 NIOX MINO is pre-calibrated and designed to be a service- and calibration-free system. The manufacturer states that the calibrated electrochemical sensors included in the test kit should be replaced every year or once all the tests in the kit have been used. It can be used alone or connected to a computer for monitoring with the NIOX MINO Data Management Program and Electronic Medical Record systems. The device is CE marked.

4.4 During the assessment phase, the manufacturer of NIOX MINO (Aerocrine) launched NIOX VERO, a new fractional exhaled nitric oxide (FeNO) device that is intended to replace NIOX MINO. The new device is battery powered and has a longer operational life and extended-test volume life compared with NIOX MINO. NIOX VERO is designed to be service and calibration free. The manufacturer states that the calibrated electrochemical sensors included in the test kit should be replaced every year or once all the tests in the kit have been used. The device is CE marked.

4.5 NObreath (Bedfont Scientific) is a diagnostic monitoring device that measures exhaled nitric oxide produced by airway inflammation. The reading is presented in parts per billion and is claimed to be directly related to the severity of inflammatory disease (for example, asthma). NObreath needs 12 seconds of exhalation of breath in adults and 10 seconds in children. The device is CE marked.