Factor XII Deficiency in ECMO Patients

Background: Extracorporeal membrane oxygenation (ECMO) for cardiopulmonary support of critically ill patients is used frequently in the pediatric and adult population. Although a lifesaving modality, it is burdened with high morbidity and mortality as a result of hematologic complications (Dalton, et al. Am J Respir Crit Care Med. 2017). Bleeding and thrombosis are related to contact of blood and its cellular components with the non-biologic surface of the extracorporeal circuit used that results in a massive inflammatory and clotting response. Factor XII deficiency is not associated with bleeding, but results in a significant prolongation of conventional coagulation assays making them unreliable for monitoring. Here we discuss 3 cases of Factor XII deficiency and the implications it has on monitoring anticoagulation in patients on ECMO. Laboratory characteristics for all 3 patients are outlined in Table 1. Case 1: Newborn full-term male with persistent pulmonary hypertension (PPHN) and meconium aspiration syndrome (MAS) with respiratory failure was placed on ECMO support on day of life 1. Patient received several units of cryoprecipitate and fresh frozen plasma (FFP) to correct deficiencies throughout his 31 day ECMO course. Patient did not have any bleeding or thrombotic complications, however he showed no improvement in lung function and decision was made to discontinue ECMO support. Case 2: Newborn full-term male with severe hypoxic ischemic encephalopathy (HIE) and MAS with secondary PPHN required ECMO support on day of life 1. His Factor XII level normalized with replacement by FFP and was decannulated after 11 days of ECMO support. This patient was discharged home with family in stable condition at 5 weeks of age. Case 3: 20-year-old female with history of recurrent astrocytoma, chronic lung disease, hydrocephalus with ventriculoperitoneal (VP) shunt, and tracheostomy presented with multifocal pneumonia and suspected sepsis. Despite fluid resuscitation and ventilatory management patient continued to have hypotension and hypoxia and thus was placed on ECMO. Prior to cannulation, patient was noted to have a coagulopathy. In addition, Factor II was low at 57% and corrected with one unit of FFP; which was thought to be related to consumptive process. On ECMO day 8, she had worsening hypotension despite vasopressor support and fixed and dilated pupils; suspected to have thromboembolic stroke and thus decision was made to withdraw life support. Discussion