Clinical Determination of Brain Death in Children Supported by Extracorporeal Membrane Oxygenation

Abstract

Background/Objective: Children supported by extracorporeal membrane oxygenation (ECMO) are at risk of catastrophic neurologic injury and brain death. Timely determination of brain death is important for minimizing psychological distress for families, resource allocation, and organ donation. Reports of successful determination of brain death in pediatric patients supported by ECMO are limited. The determination of brain death by clinical criteria requires apnea testing, which has historically been viewed as challenging in patients supported by ECMO. We report eight pediatric patients who underwent a total of 14 brain death examinations, including apnea testing, while supported by veno-arterial ECMO (VA-ECMO), resulting in six cases of clinical determination of brain death. Methods: We performed a retrospective review of the medical records of pediatric patients who underwent brain death examination while supported by VA-ECMO between 2010 and 2018 at a single tertiary care children's hospital. Results: Eight patients underwent brain death examination, including apnea testing, while supported by VA-ECMO. Six patients met criteria for brain death, while two had withdrawal of technical support after the first examination. During the majority of apnea tests (n = 13/14), the ECMO circuit was modified to achieve hypercarbia while maintaining oxygenation and hemodynamic stability. The sweep flow was decreased prior to apnea testing in ten brain death examinations, carbon dioxide was added to the circuit during three examinations, and ECMO pump flows were increased in response to hypotension during two examinations. Conclusions: Clinical determination of brain death, including apnea testing, can be performed in pediatric patients supported by ECMO. The ECMO circuit can be effectively modified during apnea testing to achieve a timely rise in carbon dioxide while maintaining oxygenation and hemodynamic stability.

Pediatric and Adult Brain Death/Death by Neurologic Criteria Consensus Guideline

“…2,3 Despite this, apnea testing is performed regularly in patients on ECMO. 32,[43][44][45][46][47][48][49] The physiologic principles when apnea testing is performed while on cardiopulmonary mechanical support with ECMO are identical to when apnea testing is performed off ECMO-respiration is stimulated in the medullary chemoreceptors by hypercarbia and secondary acidosis.…”

“…51 Adjusting the sweep gas flow rate or titrating exogenous CO 2 into the ECMO circuit lead to increased PaCO 2 levels. 32,45,47,48…”

Organ donation in patients on extracorporeal membrane oxygenation: considerations for determination of death and withdrawal of life support

“…Nevertheless, ECMO rapidly and efficiently clears CO 2, and in most cases, adjusting the ECMO settings will be necessary to ensure an adequate accumulation of CO 2while maintaining normoxia. 15 The usual practice is to decrease the sweep gas flow rate; however, at very low sweep gas flow rates, patients may become hypoxemic and hypercarbic without sufficient acidemia if the baseline pH is not normalized early in the process.…”

“…Another described strategy is to add CO 2 directly to the sweep gas flow in a controlled fashion while maintaining the total sweep flow setting (or reducing it only slightly). 15,25 This approach is preferred in situations where the requisite CO 2 cannot be achieved by reducing sweep gas alone (e.g., where hypoxemia antecedes hypercarbia).…”

The Challenges of Apnea Tests in the Determination of Brain Death in Child Patient on Extracorporeal Membrane Oxygenation

“…However, there are no consensus guidelines for the safe performance of apnea test (AT) during ECMO, as few literature exists concerning this clinical situation, especially in children (3)(4)(5)(6). We reviewed the papers and presented the experience of performing AT on a potential donor supported by ECMO to determine brain death.…”