Brain death

Brain death is a form of death that occurs when all brain activity stops. Although heart and respiratory function can be maintained through artificial means even after brain activity has stopped, brain death is a permanent and irreversible condition. In most cases, brain death is the result of some sort of severe trauma that prevents blood from flowing into the brain. When a person appears to be brain-dead, a doctor or other qualified medical professional must perform a series of tests to confirm the diagnosis. Once brain death is declared, the patient is legally considered dead. At that point, it is up to the patient's family to decide when to turn off life support devices. Often, the patient is kept on life support for a short time after brain death has been declared to give loved ones time to say their goodbyes and make the appropriate arrangements.

Brief History

In many cases, death is difficult to clearly define and diagnose. For much of human history, physicians lacked the necessary tools to determine when their patients had died. The first important breakthrough that aided doctors in diagnosing death was the invention of the stethoscope in the nineteenth century. With a stethoscope, a doctor could listen to a patient's heartbeat and breathing sounds and more precisely determine when those functions truly ceased. As a result, the diagnosis of death came to be directly and exclusively associated with the cessation of cardiovascular and respiratory activities. When ventilators and other life support machines were developed in the twentieth century, however, the definition of death became more complicated. With the introduction of these machines, it became possible to sustain cardiovascular and respiratory functions artificially even after the body was unable to do so on its own. This meant that in cases where the brain ceased to function due to trauma or disease and effectively died, the rest of the body could be kept "alive" for an extended period.

With the advent of life support machines, the medical community found itself in a difficult position when it came to diagnosing death. The most significant concern was whether a person who had lost all brain function and whose other biological functions were being sustained by artificial means could legally be described as being alive. In 1968, Harvard University organized a special committee tasked with answering this question. Ultimately, this committee recommended that such patients should be considered dead. Thirteen years later, the Harvard committee's recommendations led to the creation of the 1981 Uniform Determination of Death Act (UDDA), which legally defined death as the permanent loss of brain function. Once this law was accepted across the United States, brain death was officially recognized as a form of death. This critical development protected hospitals and physicians from most of the legal entanglements they could face concerning the status of brain-dead patients. For example, the act made it legal for physicians to harvest the organs of brain-dead patients for donation if they were organ donors or if their family agreed to donate their organs.

Overview

The human brain is divided into two main sections: the lower brain and the upper brain. The lower brain, or the brain stem, is the underside portion of the brain to which the spinal cord is connected. In function, the lower brain controls involuntary actions, such as breathing, body temperature, heartbeat, and reflexes. The upper brain, which accounts for most of the brain's mass, controls the senses and makes movement possible. Brain death occurs when both sections of the brain cease to function. What makes brain death more complicated is that certain bodily functions can continue even after the brain itself has stopped working. Because it has its own electrical system, the heart can continue to beat for a while after brain death occurs. If the patient is put on a ventilator quickly enough, cardiac function can be sustained for a longer period. Other functions, including digestive and kidney functions, can also be sustained in this manner. It is for this reason that brain death is often incorrectly thought of as something other than straightforward death.

Because of the consequences involved, declaring a patient brain-dead requires strict adherence to a thorough process that involves a series of tests designed to determine whether the patient's brain has truly stopping functioning. In most states, any physician or other qualified medical professional can conduct these tests. To ensure reliable results, some hospitals go one step further by requiring a neurologist, neurosurgeon, or neurocritical care specialist to administer the tests. Most of these tests boil down to clinical observation. Specifically, doctors will check for reflexes, determine whether the patient's pupils dilate when exposed to light, look for any response to physical stimulation, and turn off the ventilator to see if the patient can breathe on his or her own. In some cases, doctors may also use a device called an electroencephalograph to determine if there is any electrical activity in the brain. If the patient does not respond positively to these tests, brain death is usually declared. On rare occasions, a patient can be mistakenly diagnosed as brain-dead and ultimately recover. Misdiagnoses are possible because testing for brain death is imprecise. As a result, it is sometimes difficult to determine when the brain has stopped functioning. One factor that can affect the results of brain death tests is the presence of drugs like relaxants and sedatives that can mask normal brain activities. If it is known that a patient has these drugs in his or her system, testing for brain death must be delayed until they dissipate. It is also important to note that brain death is not the same as a coma. A coma is essentially a state of temporary unconsciousness that usually lasts no longer than a few weeks. Unlike brain death, brain activity does not stop during a coma.

Once a patient has been declared brain-dead, he or she may bet kept on life support for a short period to give family members time to make important end-of-life decisions and to share a few final moments with their loved one. Maintaining life support at this stage also serves to keep the patient's organs functioning so that they may later be removed for transplant.

Bibliography

"American Academy of Neurology Guidelines for Brain Death." University of Miami Miller School of Medicine,surgery.med.miami.edu/laora/clinical-operations/brain-death-diagnosis. Accessed 3 Apr. 2017.

Belkin, Gary. Death before Dying: History, Medicine, and Brain Death. Oxford University Press, 2014.

"Brain Death." National Kidney Foundation, www.kidney.org/atoz/content/braindeath. Accessed 3 Apr. 2017.

"Brain Death Still a Vexing Issue." Mayo Clinic, www.mayoclinic.org/medical-professionals/clinical-updates/trauma/brain-death-still-vexing-issue. Accessed 3 Apr. 2017.

Greenberg, Gary. "Lights Out: A New Reckoning for Brain Death." The New Yorker, 15 Jan. 2014, www.newyorker.com/tech/elements/lights-out-a-new-reckoning-for-brain-death. Accessed 3 Apr. 2017.

Jarrett, Christian. "What Is Brain Death?" Wired, 10 Feb. 2014, www.wired.com/2014/02/brain-death/. Accessed 3 Apr. 2017.

Rettner, Rachel. "Life after Brain Death: Is the Body Still 'Alive'?" LiveScience, 3 Jan. 2014, www.livescience.com/42301-brain-death-body-alive.html. Accessed 3 Apr. 2017.

Rubin, Rita. "What 'Brain-Dead' Means." WebMD, 3 Jan. 2014, www.webmd.com/brain/news/20140103/brain-dead-faq. Accessed 3 Apr. 2017.

Wilson, Jacque, and Jen Christensen. "Why Brain Dead Means Really Dead." CNN, 7 Jan. 2014, www.cnn.com/2014/01/06/health/brain-dead-basics/. Accessed 3 Apr. 2017.