Diagnosing Death in the ICU: The Moment Time Stands Still

The longest ten minutes of my life are those I spend in perfect stillness and silence in the final throes of the brain death examination.

A young woman had been admitted after a highway crash, extricated after a long two hours from twisted metal that had crushed the car roof and doors. Her pupils were fixed and dilated when she arrived. She had been intubated in the field by EMS, lips and face blue, not able to breathe on her own. We cared for her bruised body gently, but her only life-threatening injury was bleeding and swelling in her brain, compressing her brainstem—our seat of life.

We tested her neurological function repeatedly for two days, for any sign of brainstem function—for any sign of life.

Source: photo by Stephen Andrews on Unsplash

We found none. It was my job to carefully take her through the rigorous criteria we would need to pronounce her brain dead, while her heart was still beating steadily and her limbs were pale pink and warm.

Those ten minutes were mine with her. My residents were in the room, along with two medical students, her nurse, and respiratory therapist. Her mom waited just outside the door. We took her off the ventilator, which was regularly pushing air into her lungs, but still passively supplied oxygen into her lungs, to see if she would breathe on her own.

I stood by her side, my eyes never leaving her chest, watching for a breath, just a small intake or rise that would indicate her lower brainstem function still had survived and still was doing its job to literally breathe life into her.

Her chest never moved.

There are two definitions of death, as established by The Uniform Determination of Death Act, accepted by most states:

• irreversible cessation of cardiac and respiratory function, or
• irreversible loss of function of the entire brain (brain death)

In our Neuro ICU we primarily diagnose brain death. In the United States brain death requires three criteria, rigorously assessed:

• coma (and a reason for coma, such as anoxia (lack of oxygen) or cerebral bleeding)
• loss of brainstem reflexes, “brainstem areflexia” (the brainstem controls consciousness and the activities that make us alive: blood pressure, heart rate, respiration)
• loss of the ability to breathe spontaneously, tested by strict protocol in the Apnea Test for brain death

A person must meet all three criteria, without question, to be declared brain dead. No one who meets these testing criteria for brain death has ever recovered—not one person.

When We Stop the Clock

This is a time in medicine where we simply cannot be wrong. Visibly watching for a small intake of breath is important, but not enough. We already knew that the parts of her brainstem above the medulla, which controlled pupillary response, reflexive swallowing and coughing, eye movements and motor function, were no longer viable.

Brain death in the U.S. requires death of the entire brain. We still needed proof that the medulla, in the lowest part of the brainstem, where respiration is controlled, was no longer functioning. So, we sent an arterial blood gas (which measures oxygen, pH and carbon dioxide in the blood), while the patient was off the ventilator. The blood gas gives us a specific rise in carbon dioxide, enough to trigger respirations in a living person. Carbon dioxide in the blood rises in a person who is not exhaling air and it’s a powerful trigger for the brain to initiate breath. If that target carbon dioxide is met, and the person still does not breathe, they are dead.

The precise moment of death, which we record for family and write in the medical chart, is the minute that blood gas returns with the specified required rise in carbon dioxide. Usually, a respiratory therapist will put the result in my hands for me to read the numbers out loud.

Source: photo by Kevin Andre on Unsplash

To us, that moment seems arbitrary, a minute in time when we know our patient had died before, but we don’t know exactly when. But to our patients’ families, that exact moment is very meaningful: 7:06 PM. Those numbers will often be engraved on a pendant or memorialized in a tattoo. Our patient’s boyfriend told us he would do just that; get a tattoo with her first name and 7:06 on his shoulder.

That moment, when the clock stops, signaling the end of one life, will live on in the lives of those who loved her.