Purpose: Accumulating evidence suggests that organs from ECMO patients can be safely transplanted after a declaration of cardiac or brain death. However, making a diagnosis of brain death while a patient is on ECMO poses unique challenges and limited literature exists. We sought to describe the practice variations involved with declaring patients brain dead on ECMO by reviewing charts from our local organ procurement organization.Methods: After institutional review board approval, a retrospective chart review from our local organ procurement organization was performed to identify patients declared brain dead on ECMO who became organ donors. Between 1995 and 2014, we identified 26 patients on ECMO who donated organs after being diagnosed with brain death. Demographics, causes of death, clinical and ancillary studies used to pronounce brain death were recorded from charts.Results: All patients underwent one to two clinical exams as the initial step in the declaration of brain death. In addition to clinical examination, 15 (58%) of the patients underwent apnea testing, and of those, seven (47%) also had at least one ancillary test performed. Apnea testing was not utilized in 11 (42%) of the patients, and of those, nine (82%) had one or more ancillary tests performed to confirm brain death. Two (18%) patients underwent clinical examination only. Seventy-five percent of patients from 1995 -2008 underwent apnea testing compared with only 50% of patients from 2009 to 2014.Conclusions: This study demonstrated the variability of practice patterns in the declaration of brain death for patients on ECMO over time and the lack of understanding of the CO2 physiology on ECMO. Additional studies are needed to devise a national standardized protocol to declare brain death on ECMO.