and Confounding Factors
When brain injury is refractory to aggressive management and is considered nonsurvivable, with loss of consciousness and brain stem reflexes, a brain death protocol may be initiated to determine death according to
neurological criteria. Clinical evaluation typically entails 2 consecutive formal neurological examinations to
document total loss of consciousness and absence of brain stem reflexes and then apnea testing to evaluate
carbon dioxide unresponsiveness within the brain stem. Confounding factors such as use of therapeutic hypothermia, high-dose metabolic suppression, and movements associated with complex spinal reflexes, fasciculations,
or cardiogenic ventilator autotriggering may delay initiation or completion of brain death protocols. Neuro -
diagnostic studies such as 4-vessel cerebral angiography can rapidly document absence of blood flow to the
brain and decrease intervals between onset of terminal brain stem herniation and formal declaration of death
by neurological criteria. Intracranial pathophysiology leading to brain death must be considered along with clinical assessment, patterns of vital signs, and relevant diagnostic studies.
Determination of death according to neurological criteria has far-reaching implications.
Heart-beating, brain-dead donors provide the majority of organs for transplant.
times between terminal brain stem herniation, declaration of brain death, and organ recovery
risk loss of organs because of refractory cardiopulmonary instability.
A second implication is the cost
of intensive care, potentially exceeding $5000 daily.
Recognizing terminal brain stem herniation and
earlier declaration of brain death may help avoid costs associated with futile care. Last, patients who
have had terminal brain stem herniation and who are medically unsuitable for organ donation may no
longer benefit from intensive care.
Delay in determining brain death may add to the stress a patient’s
family experiences in keeping a vigil for a loved one without a chance of recovery.
From brain injury
through progression of intracranial pathophysiological changes, promoting recovery is the goal. With
refractory injury and final brain stem herniation, a brain death protocol is appropriate.
The concept of brain death dates to 1959 with the introduction of “coma dépassé,” a state beyond
coma indicating loss of life functions such as reflexes, consciousness, and mobility. In 1968 the Harvard
Pathophysiology of Brain Injury
Terminal brain stem herniation is often the final stage
in refractory brain injury caused by trauma, ischemia or
infarction, hemorrhage, intracranial tumors, and infectious processes such as encephalitis and meningitis.
Anoxic or ischemic injury after cardiopulmonary arrest
can initiate neuronal death and lead to terminal brain
Montoring, Interventions, and Family Care
Goals of frequent, dynamic neurological assessments
of patients with brain injury include identifying injury
progression, detecting stabilized neurological status or
response to therapy, and rapidly determining and acting
on opportunities for intervention before brain herniation
syndromes occur. Patient advocacy and vigilance are vital
to identify and aggressively treat consequences of injury
to other body systems at the earliest opportunity. When
evolving consequences of brain injury are identified,
patient advocacy may take the form of prioritizing aggressive, mechanism-based care in treating intracranial
pathophysiology. Advocacy, honesty, and the development of trust between a patient’s family and personnel
on the health care team markedly promote communication and rapport during a stressful and difficult time for
the family. Family members of a patient with a devastating brain injury are under stress
and need empathy,
teaching, and an environment of trust. Nurses are pivotal
to establish trust and help the family understand the torrent of information from multiple health care providers.
Taking time and building on the trust established upon
ICU admission can help the family understand brain
injury, progression of the injury, and what brain death
means. All these considerations are vital with or without
organ recovery and transplantation as possible end points.
Last edited by Medical Photos; 08-22-2015 at 12:59 PM.
Brain-specific or lipophilic tracers which cross the blood-brain barrier (eg, Tc-99m HMPAO or Tc-99m ECD) are preferred over non-specific or lipophobic tracers (eg,Tc-99m DTPA), which are considered angiographic radionuclides.
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