Prolonged Thromboelastography R Time and Thrombocytopenia as Early Warning Indicators of Bleeding in ECMO Patients Who Developed Sepsis During Support: A Retrospective Cohort Study

Objective: Bleeding is a major complication in extracorporeal membrane oxygenation (ECMO), particularly when sepsis develops during support. Conventional coagulation tests incompletely reflect haemostatic balance, and reliable early indicators of bleeding risk remain lacking. This study investigated whether dynamic changes in thromboelastography (TEG) parameters and platelet count are associated with subsequent bleeding in this population. Methods: We conducted a single-center retrospective cohort study including adult patients who developed sepsis during ECMO support between January 2021 and December 2024. Coagulation parameters were recorded at sepsis onset and within 24 hours prior to bleeding events. Major bleeding was defined according to Extracorporeal Life Support Organization criteria. A matched longitudinal analysis was additionally performed in the non-bleeding group using Day 4 after sepsis onset as a comparable observation window. Temporal changes were analyzed using paired statistical tests. Results: Sixty-four patients were included, of whom 26 (40.6%) developed major bleeding. In the bleeding group, R-time significantly prolonged prior to bleeding compared with sepsis onset (10.1 vs 7.5 min, P = 0.03), while platelet count significantly decreased (93.5 vs 110.0 × 10 9 /L, P = 0.02). In contrast, the non-bleeding group showed no significant longitudinal change in R-time (P = 0.547) or platelet count (P = 0.085) over the matched observation window. Conclusion: In ECMO patients who develop sepsis, coordinated prolongation of TEG R-time and decline in platelet count precede bleeding events and may represent early warning indicators associated with bleeding risk. These findings are hypothesis-generating and require confirmation in prospective studies. Keywords: extracorporeal membrane oxygenation, ECMO, sepsis, bleeding complications, thromboelastography, TEG, platelet count