Article Sections

Introduction

Brain and cardiac death are 2 legally acceptable definitions of death in the United States.

  • Brain death:  The heart keeps beating, but there is complete cessation of whole brain activity, including cortex (ie, coma) and brainstem (ie, apnea, cranial nerve areflexia).
  • Cardiac death:  The heart stops beating (ie, asystole).

This article focuses on brain death.

Pathogenesis

Any catastrophic neurologic event that leads to coma could potentially progress to brain death.

Etiologies

The most common etiologies are:

  • Anoxic brain injury (eg, prolonged cardiac or respiratory arrest)
  • Traumatic brain injury (eg, motorcycle collision)
  • Neurovascular accidents (eg, large subarachnoid hemorrhage)
  • Toxic-metabolic encephalopathy (eg, severe carbon monoxide poisoning)
Wakefulness and awareness

Massive neurologic catastrophes are described by alteration in:

  • Wakefulness:  generated by the reticular activating system (ie, brainstem)

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