New Guidelines for Determining Brain Death Released

The American Academy of Neurology (AAN; Saint Paul, MN, USA) has issued updated guidelines for determining brain death in adults for the first time in 15 years, providing step-by-step instructions to guide clinical decision making.

Researchers from the Mayo Clinic (Rochester, MN, USA), the University of Kansas (Kansas City, USA), and from Massachusetts General Hospital (MGH; Boston, USA) did a systematic literature search to find data for an update to the 1995 ANN brain death guideline. The researchers included a review of Medline and Embase studies from January 1996 to May 2009, which were limited to adults. The aim of the study was to answer the following questions: Are there patients who fulfill the clinical criteria of brain death who recover neurologic function? What is an adequate observation period to ensure that cessation of neurologic function is permanent? Are complex motor movements that falsely suggest retained brain function sometimes observed in brain death? What is the comparative safety of techniques for determining apnea? Are there new ancillary tests that accurately identify patients with brain death?

The researchers reported that new data have confirmed the effectiveness of earlier recommendations, and saw no evidence of recovery of neurologic function after a diagnosis of brain death, using the criteria from the 1995 practice parameter. The authors also found that in adults, complex-spontaneous motor movements and false-positive triggering of the ventilator may occur in patients who are brain dead; accordingly, there is insufficient evidence to determine the minimally acceptable observation period to ensure that neurologic functions have ceased irreversibly.

Additionally, apneic oxygenation diffusion to determine apnea is safe, but there is insufficient evidence to determine the comparative safety of techniques used for apnea testing. In addition, the researchers reported that there is insufficient evidence to determine if newer ancillary tests accurately confirm the cessation of function of the entire brain. An important clarification in the new guidelines, however, is that more than one comprehensive exam is not required for determining brain death. The new guidelines were published in the June 8, 2010, issue of Neurology.

"The brain death diagnosis can be made only after a comprehensive clinical evaluation and often involves more than 25 separate assessments,” said lead author Eelco Wijdicks, M.D., of the Mayo Clinic. "I think some people will be disappointed that we weren't able to nail this down, but this will be highly variable patient to patient, and there is no general rule.”

"To correctly diagnose brain death, it is essential clinicians adhere to a uniform framework,” added study coauthor Gary Gronseth, M.D., of the University of Kansas. "We wanted to provide useful tools to help clinicians, but many factors will still need to be based on clinical judgment.”

Brain death is a legal indicator of death that refers to the irreversible end of all brain activity due to total necrosis of the cerebral neurons due to loss of blood flow and oxygenation. Brain-stem death is considered to be the significant point, when the brain is no longer capable of sustaining the rest of the body's systems without advanced life support. The concept of brain death emerged in the 1960s, as the ability to resuscitate individuals and mechanically keep the heart and lungs functioning became prevalent.

Related Links:
American Academy of Neurology
Mayo Clinic
University of Kansas
Massachusetts General Hospital