Abstract Rationale Diagnosing bronchial asthma in children with congenital heart disease (CHD) presents a clinical challenge due to overlapping respiratory symptoms. Previous research at the Philippine Heart Center demonstrated the utility of Fractional Exhaled Nitric Oxide (FeNO) in detecting allergic conditions in this population. This study aimed to evaluate the diagnostic accuracy of FeNO in identifying bronchial asthma among pediatric patients with CHD compared with the standard. Methods This prospective cross-sectional study involved pediatric patients referred for pre-operative evaluation. Both FeNO testing and spirometry were performed at the bedside, and results were interpreted using standardized criteria. Results Twenty-eight children with CHD were enrolled. FeNO levels were significantly elevated in patients diagnosed with asthma. A FeNO threshold of 11 ppb demonstrated excellent diagnostic performance, with a sensitivity of 100%, specificity of 95.83%, positive predictive value of 80%, and negative predictive value of 100%. Spirometry parameters did not significantly differentiate between groups. The overall diagnostic accuracy of FeNO was 96.43%. Conclusions FeNO is a highly accurate and non-invasive biomarker for diagnosing bronchial asthma in children with congenital heart disease. A threshold of 11 ppb effectively identifies asthmatic patients and may serve as a valuable adjunct in pre-operative evaluations. These findings support FeNO’s integration into routine pre-operative screening and warrant validation in larger, multicenter cohorts. This abstract is funded by: None
Agudo et al. (Fri,) studied this question.