Correlation of Exhaled Nitric Oxide, Spirometry and Asthma Symptoms

Asthma is the most common chronic disease of childhood. Asthma severity is monitored by spirometry. However, this does not directly measure airway inflammation. Exhaled nitric oxide (FeNO) is a proposed method to measure airway inflammation non-invasively. Previous studies have shown that FeNO correlates with endobronchial biopsies and symptoms in patients with asthma. We monitored daily asthma symptoms compared to monthly spirometry and FeNO. Total monthly symptom scores correlated with both forced expiratory volume at 1 sec (FEV₁) and FeNO. FeNO had a strong correlation than FEV₁. FeNO and FEV₁ were not correlated. We propose that FeNO should be used as an additional monitoring tool for asthma.