How is brain death determined?
In 1995, the American Academy of Neurology (AAN) published medical practice parameters for declaring brain death detailing 3 clinical findings used to determine brain death which include: the presence of unresponsive coma, the absence of brain stem reflexes, and the absence of respiratory drive after a CO2 challenge (Rector, 2008, 30). Again in 2010, the AAN published an updated set of guidelines. Even with the 2 publications of guidelines for determining brain death, practice variations among healthcare providers continue to exist. (Spinello, 2013) (Wijdicks, 2010).
In 2005, the New York State Department of Health and the New York State Task Force on Life and the Law published revisions to the brain death determination guidelines which established responsibilities for physicians when determining brain death (Hills, 2010, 34). These include:
1. Establish proximate cause and irreversibility of coma. This is necessary in determining the true cause of death (Hills, 2010, 34). Was the cause a result of severe head trauma, hemorrhage, or aneurysm?
2. Notify the surrogate decision maker. The hospital must follow all policies when determining brain death, and must make every reasonable effort to notify the patient’s surrogate decision maker that the process of determining brain death is underway (Hills, 2010, 34). If family members reject invasive ancillary tests, physicians must seek guidance from the hospital’s legal counsel and the ethics committee (Hills, 2010, 34).
3. Clinical assessment of brain stem reflexes. The following clinical indications and observations should only be complete if the possibility of recovery has been excluded (Hills, 2010, 34). The assessments are recommended for adults 18 years and older with a normal core temperature.
Clinical Indications Clinical Observations
Coma-no evidence of responsiveness Spontaneous movements of limbs
Absence of brain stem reflexes Deep tendon reflexes
Absence of pupillary response to light in both eyes
Absence of ocular movements Respiratory-like movements
Absence of corneal reflexes Sweating, flushing, tachycardia
Absence of facial muscle movement in response to noxious stimuli
Normal blood pressure without pharmacologic support or increases in blood pressure
Absence of pharyngeal (gag) and tracheal (couch) reflexes
Absence of diabetes insipidus
4. Apnea test. The apnea test is typically the final step in the determination of brain death and usually only performed after establishing irreversibility of coma and absence of brainstem reflexes (Hills, 2010, 34).
5. Ancillary tests as appropriate. In cases of most patients with facial or cervical injuries, cardiac instability, or other factors that make the previously discussed tests incomplete or un-assessable, an ancillary test listed below will assist in verifying brain death if necessary (Hills, 2010, 34).
Ancillary tests available to assist in determining brain death: