Beyond the count: platelet dysfunction profile in pediatric trauma patients

ABSTRACT Background Existing clinical coagulation assays are inadequate to evaluate post-traumatic platelet dysfunction in children. Objectives To elucidate changes in flow-dependent platelet function following injury in children using a microfluidic assay. Methods We enrolled 18 children who presented as highest acuity trauma activation and 10 healthy children at an academic pediatric center. For control cohort, outpatient blood samples were collected, and for the trauma cohort, blood was collected in the trauma bay for conventional coagulation tests, thromboelastography (TEG), von Willebrand Factor (VWF) A1 domain activity, and a microfluidic assay using a stenotic channel (shear rate=3500s⁻¹). Results The trauma cohort characteristics were 67% male, median (IQR) age of 6 years (4-12), median (IQR) injury severity score of 17 (9-26), 78% blunt mechanism. In total, 50% required blood transfusion and 11% (2/18) died. While TEG Maximum Amplitude (59.9±6.1 mm) and platelet counts (306.3±111.1×10³ cells/μL) were within normal limits, the microfluidic assay revealed significantly lower platelet deposition in the trauma cohort versus control cohort (1.18±0.25 vs. 3.06±0.82 mean fluorescence intensity (MFI) fold change; p<0.0001). Lower levels of platelet deposition correlated with receipt of blood transfusion within 6 hours of arrival (r=-0.44,p=0.048). VWF A1 domain activity was not different between groups and was not correlated with platelet deposition based on MFI fold change (R²<0.0001). Conclusion Post-traumatic platelet dysfunction was observed in a pediatric trauma cohort utilizing a microfluidic assay. Further study is needed to understand the underlying mechanisms and significance of post-traumatic platelet dysfunction in children.