Platelet and Fibrinogen Contribution to Clot Strength in Premature Neonates with Sepsis

Background/Objectives: Platelet transfusions are administered to preterm neonates with thrombocytopenia prophylactically to decrease their bleeding risk. The amplitude difference between the extrinsic rotational thromboelastometry (EXTEM) and the fibrinogen rotational thromboelastometry (FIBTEM) assays is considered an index of platelet contribution to clot strength, guiding transfusion management. The difference in maximum clot elasticity (MCE) (namely the platelet contribution to clot elasticity-MCEplatelet) is considered highly accurate. Limited data exist to specify the contribution of platelets and fibrinogen in clot formation during sepsis in neonates with thrombocytopenia. We investigated the potential of MCFplatelet (platelet contribution to clot firmness) and MCEplatelet in reflecting platelet count and function in septic preterm neonates. We simultaneously assessed the contribution of both platelets and fibrinogen to clot strength during sepsis. Methods: We compared 28 preterm neonates with sepsis born (gestational age 24⁺¹-34⁺³) with 30 healthy counterparts by using rotational thromboelastometry (ROTEM) and platelet flow cytometry. Results: MCEplatelet showed a higher association with platelet count in the sepsis group than MCFplatelet (R² = 47.66% vs. R² = 18.79%). MCEplatelet (AUC = 0.81) had better discrimination capability than MCFplatelet (AUC = 0.78) in platelet count <100 × 10³/L. MCEplatelet was poorly associated with platelet function. The contribution of platelets was significantly lower (MCEplatelet = 84.03 vs. 89.21; p < 0.001) compared with fibrinogen (36.9 vs. 25.92; p < 0.001) in the sepsis group. Conclusions: MCEplatelet has a better predictive value than MCFplatelet. In clinical practice, the elasticity difference between EXTEM and FIBTEM may replace the amplitude difference. The higher contribution of fibrinogen in clot strength during neonatal sepsis results in higher MCF, even in neonates with thrombocytopenia.