Biomarkers in Pediatric ARDS: Future Directions

Orwoll, Benjamin E.; Sapru, Anil

There are many remaining difficulties in the pursuit of accurate and useful biomarker-based models in pARDS. One major challenge has been the establishment and widespread use of common diagnostic criteria for ARDS in children. Though consensus criteria have been available for decades in adults (4, 5), a pediatric-specific definition for ARDS, now referred to as pARDS, was only published in 2015 (6) . This definition expands upon the adult Berlin definition to allow for criteria that are more clinically relevant to pediatrics, such as unilateral radiographic infiltrates and pulse oximetry-based oxygenation metrics. It also utilizes the oxygenation index (OI), which has been well-validated in pediatric lung disease, as a risk stratification tool. This definition, as it becomes widely adopted, will help to improve the comparability between pediatric studies of ARDS, especially as the OI reflects not only the fraction of inspired oxygen but also the mean airway pressure support. Future studies of ARDS biomarkers in children should therefore strive to abide by these definitions, and indeed, many of the previously identified biomarkers of ARDS in children likely should be revalidated using the new pARDS criteria. By definition, biomarkers are found and measured in body fluids and tissues. Therefore, to measure them, it is necessary to collect biological samples from some of our societies' most vulnerable members. Children are more sensitive to collections of large volume samples than adults, and parents are often wary to allow their sick children to participate in clinical research. Fortunately, over recent years, many improvements in assay technology have allowed the development of multiplex assays that can measure dozens of proteins and other biomarkers in a single fluid sample, greatly improving the information yield from limited patient populations.