ID:60 FC-D03-8 Thrombocytopenia during ECMO Support Initially Attributed to Mechanical Consumption: A Case of Sepsis-Associated DIC with Secondary TMA Features

Background: Thrombocytopenia during extracorporeal membrane oxygenation (ECMO) is common and is often attributed to mechanical platelet consumption within the circuit. In septic shock, sepsis may also induce disseminated intravascular coagulation (DIC) and thrombotic microangiopathy (TMA), which can mimic circuit-related platelet loss. Case: A 7-month-old infant with hypoplastic left heart syndrome (HLHS) developed refractory septic shock during the postoperative course following the Norwood procedure with a right ventricle–to–pulmonary artery conduit. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) and continuous renal replacement therapy (CRRT) were initiated. Although systemic hemodynamics improved after mechanical circulatory support, profound thrombocytopenia persisted, necessitating repeated platelet transfusions. Laboratory findings indicative of hemolysis raised concern for circuit-related shear stress. Replacement of the ECMO circuit and the dialysis membrane resolved the biochemical evidence of hemolysis; however, thrombocytopenia remained refractory. Therapeutic plasma exchange was initiated as empiric treatment for suspected thrombotic thrombocytopenic purpura (TTP), but the clinical response was minimal, and progressive multiorgan failure ensued. Subsequent testing demonstrated an ADAMTS13 activity of 46%, rendering TTP unlikely. Blood cultures obtained at the onset of clinical deterioration subsequently grew Klebsiella oxytoca several days later. Thereafter, cultures repeatedly returned positive with progressively shorter time-to-positivity, consistent with persistent and worsening bacteremia. Serial coagulation profiles consistently suggested DIC with a suppressed fibrinolytic phenotype. Although decreased ADAMTS13 activity secondary to hypercytokinemia and the development of secondary TMA were considered, as described in prior reports, we ultimately concluded that inadequate infection control was the primary driver of the persistent thrombocytopenia in this case. Discussion: In septic patients supported with ECMO, persistent thrombocytopenia should prompt a systematic differential diagnosis–including circuit-related factors, sepsis-associated DIC, and secondary TMA–with repeated reassessment over time. Consumption: may delay recognition of inadequate infection control and adversely affect clinical outcomes.