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One reason family members may not accept a loved one’s brain death in the ICU as death is the plausible possibility of underlying brain and physical vitality.

A middle-aged woman recently suffered an out-of-hospital cardiac arrest. With prolonged resuscitation, she achieved return of spontaneous circulation and received targeted temperature management and other aspects of the post-cardiac arrest care bundle. Unfortunately, the patient developed severe hypoxic-ischemic brain injury, evident on MRI scan and, over the next few days, demonstrated diminishing brain function, so that by Hospital Day 6, she had fulfilled the criteria, including a positive apnea test, for a determination of brain death/death by neurologic criteria (BD/DNC).

Tearfully, her husband turned to me and exclaimed, “How can you say she is dead? I can see her breathing, and that [pointing to the bedside monitor] shows her heart beating fine. And she sometimes moves when I touch her hand or leg.”

Was he wrong?

For millennia, death has been defined as the absence of heartbeat and respiration. In the 1960s, with the advent of mechanical ventilation and other supports, the concept of brain death was considered. In 1968, a committee from Harvard Medical School suggested that death ought to be diagnosed when there was complete and irreversible cessation of brain activity, even if there continued to be functioning of the lungs, heart, and other organs. This concept became more generally applied throughout the US and the world and eventually became a legal standard in most countries. In 1981, the Uniform Determination of Death Act was passed, equating brain death to death in the US. It was stipulated that these determinations should be made in accordance with accepted medical standards. In the late 2010s, some medical societies agreed that these standards were served by the guidelines promulgated by the American Academy of Neurology (AAN) and other organizations, effectively establishing a national standard of care. Despite claims of previous authority, these guidelines were ‘updated’ in 2023.

BD/DNC is generally defined (per the 2023 guidelines of the AAN and other organizations) as permanent loss of function of the entire brain, including the brain stem, resulting in coma, brainstem areflexia, and apnea in the presence of adequate stimulus. I am discussing this issue only as it pertains to adults.

Why Do Some People Deny a Brain Dead Patient Is Dead?

BD/DNC as a concept has only existed for around 60 years, while vitalism has been present in culture and religion for thousands of years and ought, therefore, to be granted some respect. Families may have diverse philosophical, religious, or cultural reasons for not accepting brain death as death; however, some are focused on the circumstances of the BD/DNC patient and the real or at least plausible possibility of underlying brain and physical vitality, seemingly suggesting the possibility of recovery.

Brain dead patients may have many characteristics commonly (and traditionally) associated with life and not death:

• They may maintain normal heartbeat, cardiovascular function, stable hemodynamics, immunologic competency, and organic perfusion.
• They may trigger the ventilator through cardiac oscillation, appearing to have spontaneous respirations. This may necessitate decreasing the ventilator’s flow trigger sensitivity, a process that may not seem intuitive to patients’ families.
• They may, and usually do, maintain body temperature.
• Around 50% of patients diagnosed with BD/DNC maintain hypothalamic neuroendocrine function, meaning they do not develop diabetes insipidus or other hormonal deficits. As this finding indicates retained brain function, it is considered a one-time exception to the ‘entire brain’ criterion—again, an exception that may not seem intuitive to some.
• Patients commonly continue to move with and without stimulation in a variety of reflexive ways, ranging from deep tendon reflexes to flexion of the fingers and toes in response to stimulation to dramatic responses such as truncal spasm, which may simulate a patient attempting to sit up, or the Lazarus sign, in which head-turning results in impressive flexion of the neck and both arms. Often, only a careful neurologic examination by an experienced specialist can ensure these movements are reflexive and not volitional in origin.
• Brain dead patients may reproduce, although this is a rare occurrence.

Given these issues, it is reasonable that families may consider some BD/DNC patients as alive or, like Schrödinger’s cat, potentially living or dead. Sympathetic education and counseling are vitally important, but absolute certainty of BD/DNC is a sine qua non. The accepted criteria for diagnosis of BD/DNC should be closely followed with no corners cut, particularly for potential organ donation. Studies have suggested that many or even most US physicians do not carry out ‘brain death’ evaluations appropriately, compatible with the AAN guidelines, particularly related to an over-reliance on ancillary testing over clinical examination. The most common issue here deals with the residual effects of sedatives, analgesics, or neuromuscular blockade agents. These agents should be held for a minimum of five half-lives before BD/DNC determination, even understanding the half-lives themselves are not fully agreed upon, particularly in a critically ill patient with organic dysfunction. Repeated and delayed examinations should be considered if any questions still exist. It will be most difficult to explain to an aggrieved family member that the original determination of BD/DNC was in error.

I agree with the AAN that this determination should be approached, as in other scientific inquiry, as a presumption of life—to disprove the null hypothesis—rather than err on determination.

As families may not yet recognize BD/DNC as death, additional contemplation and activity will be necessary and will be discussed in the next Tales From the ICU column.