Brain Death Criteria

Excerpt

Death is defined in the United States by the Uniform Determination of Death Act (UDDA), proposed in 1981. A determination of death must be made in accordance with the accepted medical standards and must additionally include one of the following:

1. Irreversible cessation of circulatory and pulmonary functions.

2. Irreversible cessation of all functions of the entire brain, including the brainstem, is dead.

The UDDA was drafted in the late 1970s in response to medical advances in life support that allowed for complete circulatory and respiratory support despite complete cessation of brain function. The UDDA did not establish what "accepted medical standards" were; instead, only that they existed. The American Academy of Neurology (AAN) published the initial standards in 1995, which were updated in 2010 to the current standards.

AAN's recent position statement on brain death endorses UDDA's death definition as "irreversible loss of entire brain, including the brainstem, has been determined by the demonstration of complete loss of consciousness (coma), brainstem reflexes, and the independent capacity for the ventilatory drive (apnea), in the absence of any factors that imply possible reversibility." Irreversibility in the definition of death refers to the impossibility of recovery, regardless of any medical intervention, which requires clear elaboration, as with the advancement of mechanical ventilation and life support technologies during the 20th century, patients who suffered severe brain damage could be maintained physiologically for prolonged periods in intensive care units (ICUs). AAN, in addition, believes "preserved neuroendocrine function may be present despite irreversible injury of the cerebral hemispheres and brainstem and is not inconsistent with the whole brain standard of death."

In 2012, the World Health Organization (WHO) partnered with an international forum to endorse brain death as the official diagnosis of death. However, internationally and even within different states of the United States, there is no uniformity to certify brain death. Brain death criteria also differ based on the patient's age. Therefore, different criteria are in effect to perform a document of brain death, and the provider should be cognizant of their country/state's criteria for a specific patient's age.

It is essential to distinguish the term "brain death" from "coma" to the public, as coma may imply a limited form of life. The understanding that brain death is equivalent to death helps guide decision-making for both physicians and patients' families regarding the withdrawal of care and prevents the unnecessary expenditure of resources. An essential topic that evolved in parallel with brain death is obtaining organs for transplantation. According to the "dead donor rule," organ procurement can occur only after death has been declared. Therefore, for patients who are brain dead, the procurement of viable organs is allowed, even if a patient still has some circulatory and/or pulmonary function. This concept continues to result in some ongoing debate and controversy.

It is also crucial to differentiate brain death from other forms of severe brain damage, including vegetative state (VS) and minimally responsive state (MRS). In VS and MRS, some brain functions are maintained, resulting in a chance of recovery, even occasionally after prolonged periods, especially in patients with traumatic brain injury (TBI).