Challenges in Brain Death Determination in Extracorporeal Membrane Oxygenation – A Single Center Experience

Abstract

Background Conducting an apnea test (AT) in patients on extracorporeal membrane oxygenation (ECMO) support is challenging, leading to variable approaches for determining brain death (BD), also known as death by neurologic criteria (DNC). This study aims to describe the diagnostic criteria and barriers for DNC in a high-volume ECMO center with an emphasis on the role of AT. Methods A retrospective review of a prospective observational standardized neuromonitoring study was conducted in adult VA- and VV-ECMO patients at a tertiary center from June 2016-March 2022. Brain death was defined according to the 2010 American Academy of Neurology guidelines. AT for DNC in this study was performed in accordance with the 2020 Journal of the American Medical Association BD/DNC criteria recommendations for ECMO patients, including a period of pre-oxygenation, setting ECMO sweep to 0.5-1 L/min, and measuring serial blood gases. Results During the study period, 15 of 300 (5%) patients underwent testing for DNC. Eight (2.7%) ECMO patients (median age = 44 years, 75% male, and 50% VA-ECMO) were diagnosed with BD, six (75%) of whom were determined with AT. In the other two patients who did not undergo AT due to safety concerns, ancillary tests (TCD and EEG) were consistent with BD and the patients were declared BD on the basis of those findings. An additional seven (2.3%) patients (median age = 55 years, 71% male, and 86% VA ECMO) were noted to have absent brainstem reflexes but failed to complete determination of DNC as they underwent withdrawal of life-sustaining treatment due to family wishes before a full evaluation was completed. Six (86%) of these patients with unconfirmed BD had at least one ancillary test performed that were not consistent with BD despite either neurological exam findings and/or AT results supporting a BD diagnosis. In the seventh patient, although absent brainstem reflexes were noted on the neurological exam with explanatory findings on imaging, there was no AT or ancillary testing done. Conclusion AT was used safely and successfully in 6 of the 8 ECMO patients diagnosed with BD, though providers were more confident using AT with ancillary tests. AT was always consistent with the neurological exam and imaging findings suggesting BD. However, there are limitations to ancillary tests for BD assessments when used without AT and we recommend performing at least two ancillary tests to confirm brain death if AT cannot be performed or is inconclusive in ECMO patients.