Fractional exhaled nitric oxide monitoring in paediatric asthma management

Abstract

An annual review is recommended for children with asthma but objective measures of control are lacking.1 Monitoring exacerbations and a symptom score are both suggested, but the widely used Children’s Asthma Control Test (C-ACT) has a positive predictive value of only 46.7% for asthma exacerbations at the recommended score of <24/27.2 Additional tests such as peak expiratory flow or spirometry have not been shown to improve quality of life or symptom scores compared with symptom-based management.3 Fractional exhaled nitric oxide (FeNO) may provide additional information, such as quantifying eosinophilic airway inflammation to identify patients more likely to benefit from an adjustment in their inhaled corticosteroid (ICS) regimen over other treatment options. The National Institute for Health and Care Excellence (NICE) has evaluated three portable, hand-held devices that measure exhaled nitric oxide, produced in proportion to inflammation in the lungs: NObreath, NIOX VERO, and NIOX MINO.1 The devices cost between £1794–£2540, plus £4.93–£9.35 per test for the sensor and filter. Each is accurate to +/−5 ppb (parts per billion) and tend to be precise to <10% of the measured value. Child-friendly versions are available and FeNO monitoring has been shown to be reproducible and feasible in children aged ≥4 years. FeNO levels may help targeted optimisation of ICS dosing in children. In particular, FeNO could help decide whether children aged ≥5 years with suboptimal asthma control, despite treatment with …