Brain death: a clinical overview

Abstract

Brain death, also commonly referred to as death by neurologic criteria, has been considered a legal definition of death for decades. Its determination involves many considerations and subtleties. In this review, we discuss the philosophy and history of brain death, its clinical determination, and special considerations. We discuss performance of the main clinical components of the brain death exam: assessment of coma, cranial nerves, motor testing, and apnea testing. We also discuss common ancillary tests, including advantages and pitfalls. Special discussion is given to extracorporeal membrane oxygenation, target temperature management, and determination of brain death in pediatric populations. Lastly, we discuss existing controversies and future directions in the field.

Brain death/death by neurologic criteria determination: an update

“…Once the diagnosis is clear, it must be proven that the brain injury is irreversible, meaning that loss of function is complete and constant over time and cannot be reversed. There is no consensus concerning the timing of observations [11]. However, if a patient is admitted after return of spontaneous circulation following cardiopulmonary resuscitation, a delay of at least 24 h is recommended [11].…”

“…As a general rule, as with any phase, if there is any doubt about reversibility, clinicians should delay performance of testing to exclude any doubt [1 ▪▪ ]. The clinical determination of brain death/DNC includes an assessment for coma and an evaluation for loss of brainstem functions [1 ▪▪ ,6,11]. The following tests must be performed according to the WBDP and AAN criteria [1 ▪▪ ,17,26]: There is no brain-mediated motor response to noxious stimulation of the limbs.…”

“…The gag reflex is absent to bilateral posterior pharyngeal stimulation. There is no cough reflex in response to deep tracheal suctioning [1 ▪▪ ,11,17,27]. Spears et al published detailed guidance on how to perform these tests [11].…”

“…There is no cough reflex in response to deep tracheal suctioning [1 ▪▪ ,11,17,27]. Spears et al published detailed guidance on how to perform these tests [11]. In order to determine brain death/DNC, the absence of brainstem function is an absolute requisite and, especially since it is based on clinical neurological examination, an essential phase in determining brain death/DNC.…”

“…After all, if there is an infratentorial or brainstem lesion and the whole brain death concept is valid, ancillary tests are needed to demonstrate that there is no longer any cortical function [10]. Recent publications recommend that the terms ’whole brain death’ and ’brainstem death’ should no longer be used and should be replaced by brain death/DNC [1 ▪▪ ,3 ▪ ,11].…”