Volatile organic compounds and the relevance of background correction in the early prediction of bronchopulmonary dysplasia in preterm infants

<bold>Rationale:</bold> Volatile organic compounds (VOCs) in exhaled breath, reflecting inflammation and oxidative stress, shows potential for non-invasive monitoring of bronchopulmonary dysplasia (BPD). However, measured VOCs also include 'background VOCs' from the environment and medical devices. Despite their importance, this exposure source is mostly not considered in BPD research. <bold>Methods:</bold> Exhaled breath samples from BPD patients born ≤ 30 weeks’ gestation on non-invasive respiratory support (n=5) were analysed alongside preterm controls (n=5) on day 28 of life. Background samples from the set-up under similar conditions were obtained to account for VOCs specific to the ventilatory circuit. Samples were analysed using proton transfer reaction high-resolution mass spectrometry (PTR-HRMS). <bold>Results:</bold> Some VOCs were more abundant in background than in patient samples, but only significant compared to preterm controls: m/z164.0967; m/z163.0966; m/z91.0566 (methyl propyl sulfide); m/z74.04649 (N,N-dimethylformamide); m/z73.0463; m/z72.9368; m/z54.0338; m/z54.0089; m/z45.0339 (ethylene oxide); m/z44.979. VOC with m/z72.9368 was only present in the background. <bold>Conclusions:</bold> Some background VOCs are no longer abundant in breath samples, suggesting an exogenous origin. The different abundance of these VOCs in BPD breath samples and preterm controls might suggest metabolisation to a greater or lesser extent, yet their potential link to BPD development remains unclear. These findings highlight the importance of background sampling. Further research is needed to explore common exogenous VOCs and their impact on BPD development.