Brain Death Criteria

Death is defined in the United States by the Uniform Determination of Death Act, proposed in 1981, as 1. Irreversible cessation of circulatory and pulmonary functions. 2. Irreversible cessation of all functions of the whole brain, which means brain death. The definition of brain death or irreversible coma as "loss of brain functions" was released by the Ad Hoc Committee of the Harvard Medical School in 1968. The American Academy of Neurology (AAN) guidelines of brain death determination ascertained this definition and released its first version in 1995. According to the AAN guidelines, brain death is clinically equivalent to the irreversible loss of all brain stem functions. Irreversibility in the definition refers to the impossibility of recovery, regardless of any medical intervention, which required 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 the ICUs.[1][2][3] It is crucial to differentiate brain death from other forms of severe brain damage, which can cause vegetative states when some of the brain functions are maintained, and recovery can occur even after prolonged periods, especially in patients with traumatic brain injuries. Also, it is important to distinguish the term "brain death" from "coma" to the public, as coma may imply a limited form of life. Understanding that brain death is equivalent to death helps both the physicians and patients' families to decide about the withdrawal of care and prevents the unnecessary expenditure of resources. Another essential topic that evolved in parallel of brain death is the need of obtaining organs for transplantation. According to the "dead donor rule," organ procurement can occur only after death. So for patients who are brain dead, the procurement of viable organs is allowed, even if they still have some circulatory and pulmonary functions. This concept is still causing an ongoing debate and controversy.[4][5][6]