Are serum thrombomodulin and interleukin-8 levels associated with disease severity and mortality in critically ill children with respiratory failure?

Background/aim: Thrombomodulin (TM) is found on endothelial cell surfaces and increases in response to endothelial injury of different organs. Interleukin (IL)-8 regulates pulmonary inflammation. TM and IL-8 are candidate biological markers of acute respiratory distress syndrome (ARDS). The aim of the present study was to compare TM and IL-8 levels in pediatric patients with and without ARDS who received respiratory support and to determine their relationships with prognosis.

Materials and methods: This was a prospective observational study of 55 patients who received respiratory support in the pediatric intensive care unit. Eighteen patients without active infection were defined as the control group. Two blood samples were taken for serum IL-8 and TM levels on the first and third days of respiratory support.

Results: The patient group had significantly higher IL-8 and TM levels than the control group [median IL-8: 102.7 (IQR: 180.42-189.47) vs. 45.4 (55.14-70.49) ng/L, p = 0.011; median TM: 6.9 (6.83-9.18) vs. 3.4 (3.62-5.05) ng/mL, p = 0.021]. Patients with ARDS had significantly higher marker levels on the first and third days than those who did not have ARDS. The TM and IL-8 levels of deceased patients were significantly higher than those of the survivors on the first day. In mortality prediction, the cut-off point for IL-8 was found to be >154.7 ng/L, which had sensitivity of 76.9% and specificity of 73.8%. The cut-off point for TM was >8.4 ng/mL, which had sensitivity of 76.9% and specificity of 66.7%.

Conclusion: In our study, higher marker levels correlated with impaired oxygenation and higher mortality. Higher TM and IL-8 levels in ARDS might reflect the degree of vascular injury and inflammation.