Late Breaking Abstract - Exhaled breath biomarkers in severe acute asthma admitted to the pediatric intensive care unit.

<bold>Background:</bold> Admissions of children with severe acute asthma (SAA) at the pediatric intensive care unit (PICU) have increased worldwide, which may suggest a change in immunological endotype. However, the identification of these immunological endotypes is lacking in this patient group. With breathomics, a non-invasive technique, biomarkers such as volatile organic compounds (VOCs) can be measured and used to identify correlating pathologic processes. <bold>Aim:</bold> To study whether VOCs associated with asthma exacerbations are present in SAA in comparison to children with controlled asthma to improve the knowledge of their pathophysiologic significance, and ultimately help endotype guided treatment. <bold>Methods:</bold> A literature search was performed in Pubmed to identify VOCs associated with asthma exacerbation. Breath samples of children between 4-18 years with SAA admitted to the PICU were analyzed using gas chromatography-mass spectrometry. The VOCs and their abundance were compared with children with controlled asthma (CA) using an unpaired Wilcoxon rank sum test in Rstudio. <bold>Results:</bold> Twenty-five targeted VOCs associated with asthma exacerbations were identified in the literature. In total, 44 breath samples were analyzed, 17 in the SAA-group en 27 in the CA-group. Of the 25 targeted VOCs, 16 were found of which 9 VOCs had a significantly higher concentration in the SAA-group compared to the CA-group. <bold>Conclusions:</bold> This study found 9 VOCs associated with asthma exacerbation in SAA with a significantly higher concentration compared to CA, which may imply their pathophysiologic significance in uncontrolled asthma.