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Neurology Now:
doi: 10.1097/01.NNN.0000383094.28196.42
Features: Brain Death and Organ Donation

Making Sense of Brain Death

SHAW, GINA

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Abstract

Understanding brain death and organ donation is crucial for patients, families, and doctors. Here's what you should know.

A 78-year-old retired banker was playing poker with some old friends when he collapsed at the card table. (Names have been withheld and some details changed to protect privacy.) Brought to the local emergency room, the man underwent a computed tomography (CT) scan, which generates three-dimensional images of the inside of the body. The scan showed massive bleeding into his brain stem. This important part of the brain helps regulate breathing, heart function, and the central nervous system. He had suffered a hemorrhagic stroke, which is caused by the bursting of a blood vessel in the brain.

FIGURE. THE DIAGNOSI...
FIGURE. THE DIAGNOSI...
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The man was admitted to the intensive care unit and put on a breathing tube to protect his airway. The neurologist who examined him found that the banker was in a complete, unresponsive coma. The man didn't open his eyes or move his head in response to pain. He didn't breathe on his own. All brain stem reflexes'such as the pupils of the eyes dilating in response to a light shined directly at them'were absent. For 12 hours, the man remained in this condition: He had no brain function but was otherwise stable, with a normal temperature, heart rate, and blood pressure.

The next morning, the neurologist went to sit with the patient's distraught wife in the waiting room. “I'm sorry,” he said. “We've done everything we can, but the damage to your husband's brain was too extensive. His heart is still beating, and we are sustaining his breathing with a ventilator, but he cannot breathe on his own. Although his heart is beating, his brain has died.”

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BRAIN DEATH MEANS DEATH

The doctor did not tell the woman that her husband was dead'not in those blunt words. But when the brain has died, there is absolutely no prospect of recovery, even though the heart may still be beating with the help of artificial life support.

“Brain death is as valid a definition of death as if your heart had stopped beating,” says Gary Gronseth, M.D., professor and vice chair of neurology at the University of Kansas Medical Center in Kansas City, KS. “If you're brain dead, you're dead.”

FIGURE. BRAIN DEATH ...
FIGURE. BRAIN DEATH ...
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Understanding just what constitutes brain death, and how it differs from other brain injuries, is an issue that has confused and troubled patients, families, and doctors for a long time.

To help clear up this confusion, the American Academy of Neurology (AAN) is issuing a “practice guideline” on June 8, 2010, for managing brain death in adult patients. The AAN develops such guidelines to help neurologists make decisions about the prevention, diagnosis, treatment, and prognosis of neurologic disorders. Each guideline makes specific recommendations based upon a rigorous and comprehensive evaluation of all available scientific evidence. The last guidelines on the subject of brain death were issued in 1995.

“Much more is spelled out with the new guideline. It addresses, in a more in-depth way, the evidence behind what we as neurologists do and the details of determining brain death. And it provides a checklist,” says David Greer, M.D., associate professor of neurology at Harvard Medical School in Boston, MA. In 2008, Dr. Greer authored an article in the AAN's medical journal Neurology that found significant differences in how U.S. hospitals determined brain death. “Probably one of the most important things in the new guideline is the checklist, which clinicians can take to the bedside to make sure everything is being done with the utmost accuracy and reliability,” Dr. Greer says.

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DETERMINING BRAIN DEATH

So how do doctors determine when someone is brain dead? There are several key requirements, Dr. Gronseth explains. First, the patient must undergo a complete neurologic examination. That examination must find that the patient is in an unresponsive coma, has no brain stem reflexes, and is unable to breathe on his own. Second, doctors must know the cause of the coma. Third, there must have been a sufficient observation period to ensure that the patient cannot recover. The length of this period depends on the patient's condition. Last, there cannot be any confounding and potentially reversible conditions, such as low body temperature, that could be causing the appearance of brain death.

“When doctors declare someone brain dead, families sometimes fear that they will do so prematurely,” says Dr. Gronseth. “But when people have read in newspapers or magazines about patients who have been wrongly declared brain dead, this fundamental framework has not been followed. There has never been a single case reported of a physician following these requirements and declaring someone brain dead, only to turn out to be wrong. These new guideline will help make sure that diagnosing brain death is clear and unambiguous.”

Research has shown that brain-death determination isn't always done the same way at every hospital. “The new guideline is designed to decrease that variability, so that the public can be sure these decisions are being made in the proper way,” explains Dr. Greer.

Don't doctors need some other kind of test besides the complete neurologic examination to make sure the brain stem isn't working? An MRI or an EEG, for example?

No, says Dr. Gronseth. “Tests like these are not as good as the complete neurological workup. They're done on occasion when the neurological exam can't be done. For example, if the patient is so unstable that doctors can't test her ability to breathe on her own'by shutting off the vent'then they may do an additional test to measure breathing. But otherwise, in adults at least, it's not necessary to do any additional kind of advanced testing to determine brain death.”

The guideline is restricted to adult patients because of the more “plastic” nature of a child's brain. “Children's brain injuries are more reversible and have a higher potential for recovery,” says Dr. Gronseth. “In addition to the detailed neurologic exam, in some cases, children thought to be brain dead will also require additional kinds of testing, such as an electroencephalogram, which measures electrical activity in the brain, or a cerebral blood-flow study.”

FIGURE. NO BRAIN ACT...
FIGURE. NO BRAIN ACT...
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The observation period for declaring someone brain dead will vary depending on the age of the patient and the injury he suffered. For example, that 78-year-old banker with the devastating brain hemorrhage was declared brain dead after his condition remained unchanged for 12 hours. A nine-year-old boy whose brain injury was due to lack of oxygen after drowning might have to be observed for at least 48 hours'especially if the water he fell into was very cold. (Low body temperature can cause the appearance of brain death.)

Are there specific rules as to how long you need to watch each patient, or how high body temperature would have to be after, say, drowning in a cold lake? “These are issues that require a lot of individual judgment, based on the patient's circumstances,” says Dr. Gronseth. “The guideline defines the process for declaring brain death much more precisely than before, but to some extent doctors still have to rely on their clinical judgment.”

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WHAT BRAIN DEATH IS NOT

The idea of brain death can be confusing. For example, the new guideline talks about a lack of brain stem reflexes. But exactly what are brain stem reflexes? If a neurologist sits at the bedside of a patient on life support and scratches the sole of her foot with a needle, the patient will probably pull her foot away. Does that mean she isn't brain dead?

Not necessarily'because that particular reflex is controlled by the spinal cord and not the brain or brain stem. The brain stem controls certain automatic functions of the body, like breathing, blinking, and swallowing. If a neurologist shines a flashlight in the eyes of a person who is brain dead, her pupils will not contract. If the doctor puts his finger on her eye, she will not blink. But other reflexes, like the foot-scratch reflex and the automatic jerk that happens when a doctor taps the right spot on your knee with a hammer, continue even when someone is brain dead.

Brain death is very different from other types of catastrophic brain injury. Sometimes, when people hear “brain death,” they think of Terri Schiavo, who spent 15 years in an institution after collapsing at home and spending a long period without oxygen. After a court case that sparked national controversy, Schiavo's feeding tube was ultimately disconnected and she passed away in 2005. But Schiavo was not brain dead; she was in a persistent vegetative state. That means that she didn't require a ventilator to breathe, and she opened her eyes and blinked and swallowed'all things that someone who is brain dead cannot do and will never regain the ability to do.

“Patients in a persistent vegetative state are in a persistent coma, but the lower brain centers are intact. The brain stem works,” says Dr. Gronseth. It can be very difficult to determine how much consciousness people in a persistent vegetative state still have'but in any case, their condition is very different from brain death. “In brain death, the entire brain, including the lower centers, isn't working and won't recover.”

How can a family know that their physician is following the AAN guideline when assessing brain function? Don't be afraid to ask questions. “Ask the doctor if he's comfortable with this determination, if he's done it before, and what he bases the diagnosis on,” says Dr. Gronseth. “Ask if he's familiar with the new AAN guideline.”(You can download the AAN brain death guidelines for free at aan.com/guidelines; search for “brain death.”)

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THE GIFT OF A LIFETIME

Once someone is declared brain dead, the question of organ donation often comes up. But it can be difficult to think clearly after a doctor has just informed you that your loved one will never recover from his injuries. If you wait to make the decision to take your family member off life support, will it mean that she cannot be an organ donor?

You have some time to decide, Dr. Gronseth says. “There can be a lot of time, depending on how stable the patient is. A lot depends on how sick they are in terms of their other organs, their blood pressure, breathing, and heart rate. But there is usually not a rush, and there is a whole protocol that organ donation professionals go through to maintain these organs. It's not uncommon for the body to be maintained by artificial means for a day or two while a transplant team is being mobilized.”

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FIGURE. HANDLE WITH ...
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The new guideline, says Dr. Greer, should be very reassuring to patients and their families dealing with any kind of catastrophic brain injury. “People do have a mistrust about brain death and organ donation,” he says. “There is some fear that doctors will declare a loved one brain dead prematurely, out of a desire to have their organs donated.”

This is definitely untrue, says Dr. Gronseth. “The person doing the determination of brain death is completely separate from the organ transplant professionals. Organ donation is completely secondary. Before the patient is declared brain dead, no one will bring up the prospect of organ donation unless the family asks.”

Over 100,000 people are currently waiting for a transplant in the United States. On average, people wait about three to eight months for a heart, around a year for a liver, 15 months to two years for a lung, and three to five years for a kidney. Every day, 16 people die while awaiting a transplant.

“For families who have gone through such a devastating loss, organ donation can be a big part of the healing process,” says Dr. Greer. “Knowing that your loved one has lived on in some way to help other people is a very powerful thing.”

©2010 American Academy of Neurology

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