Determining Brain Death Made Easier in New AAN Guidelines

In an effort to create a uniform and accurate method for determining brain death, the American Academy of Neurology (AAN) has issued a revised guideline that provides physicians with a step-by-step process for determining brain death in adults. The guideline is 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. The new guideline includes a checklist that will help doctors with this diagnosis,” said lead guideline author Eelco Wijdicks, MD, PhD, with the Mayo Clinic in Rochester, MN, and Fellow of the AAN.

The goal was to provide an update of the 1995 AAN guideline with regard to determining issues such as what is an adequate observation period to ensure that cessation of neurologic function is permanent; whether there are patients who fulfill the clinical criteria of brain death who recover neurologic function; whether complex motor movements that falsely suggest retained brain function are observed in brain death. It also sought to assess the safety of techniques for determining apnea and determine whether there are new ancillary tests that accurately identify patients with brain death.

The 2010 update confirms the previous findings and provides specific steps for meeting the legal standards of brain death diagnosis. It stresses three signs that a person's brain has permanently stopped functioning. First, the person is comatose, and the cause of the coma is known. Second, all brainstem reflexes have permanently stopped working. Third, breathing has permanently stopped. A ventilator, or breathing machine, must be used to keep the body functioning.

“In adults, there are no published reports of recovery of neurologic function after a diagnosis of brain death using the criteria reviewed in the 1995 American Academy of Neurology practice parameter,” says the new guideline. “Complex-spontaneous motor movements and false positive triggering of the ventilator may occur in patients who are brain dead. There is insufficient evidence to determine the minimally acceptable observation period to ensure that neurologic functions have ceased irreversibly.” Although apneic oxygenation diffusion to determine is safe, there is insufficient evidence to determine either the comparative safety of techniques used for apnea testing, or whether newer ancillary tests accurately confirm the cessation of function of the entire brain.