Use of exhaled nitric oxide in children with bronchial asthma

Background

Inflammation is an important aspect of the pathophysiology of bronchial asthma and measurement of inflammatory markers of airways can aid in management. Nitric oxide measurement in exhaled breath is a non-invasive method of determining airway inflammation which can be used in assessing severity and response to treatment in children with bronchial asthma.

Methods

Thirty children in the age group 6–14 years with previously or newly diagnosed bronchial asthma reporting for the first time to a tertiary care hospital constituted the study group. Assessment was done by history, clinical examination, spirometry and measurement of fractional excretion of nitric oxide (FeNO) before commencement of treatment as per standard guidelines and on follow up at 2 to 4 weeks intervals for a minimum of three times.

Results

There was significant correlation between FeNO values, spirometry parameters and clinical profile in the first visit before the initiation of therapy. Children with higher FeNO in the first visit responded better to Inhaled Corticosteroids (ICS) with good clinical and spirometry responses and fall in FeNO on second visit. However, in subsequent visits no significant correlation was observed between clinical control, FeNO levels and spirometry.

Conclusion

High FeNO values at first presentation could give us a clue as to whether or not a child would respond to ICS but FeNO monitoring may not be helpful in long term follow up as various other factors can affect its value.