Brain Death

Medical experts and respected medical institutions define brain death in many ways. One example is: "Death caused by complete and irreversible loss of function of the entire brain, including the brain stem." The brain is no longer alive and cannot be brought back to life. But the use of machines and technology can keep many other organs functioning normally. The determination of brain death depends on very definite clinical and laboratory findings.

Clinically, a person is brain dead when all of the following conditions are met:

  • The person cannot take a single breath on his/her own (no spontaneous respirations).

  • The black of the eyes (pupil) is open between 4 and 6 mm (millimeters). The pupils do not react to light.

  • The person is in a coma. Painful stimulation provokes no eye blink, no grimacing, and no movements of any part of the body.

  • There is no movement, no muscle tone, and no reflex activity in the arms or legs (flaccid extremities).

  • There are no signs of brain stem activity:

  • The eyeballs are fixed in the eye sockets (orbits). This does not change with movement of the head.

  • Stroking the clear part of the eye with a fine wisp of cotton does not produce any movement of the eyelids (no corneal reflexes).

  • Exposing the eardrum to ice cold water (caloric testing) does not produce movement of the eyes.

  • There is no gag reflex or cough reflex.

Sometimes, a person cannot yet be declared brain dead, even when all of the findings above have been met. Various drugs (narcotics, sedatives, anesthetics), reversible head injury, low body temperature, and a few diseases can make someone appear to be brain dead. The caregiver must be sure that all of these causes have been considered, before concluding that the person is brain dead.

Confirmatory testing is required by law, in some countries. In others, the choice of tests is left to the caregiver. Some tests are:

  • Injection of a dye into the arteries of the neck, to show on X-ray films how blood moves through the arteries of the brain (cerebral angiogram). If brain dead, results will show no movement of dye into the arteries of the brain.

  • Scan of the head, after a safe radioactive substance is injected in the veins (cerebral blood flow scan). If brain dead, shows no blood flow in the brain.

  • Two EEGs (electroencephalograms, brain wave tests) at about 24-hour intervals. If brain dead, will show no electrical activity coming from the brain.

  • Ultrasound (transcranial Doppler ultrasonography) using harmless, low intensity sound waves to detect blood flow to the brain. If brain dead, no blood flow will be detected.

The EEG is used in many countries. It is one of the most well-validated confirmatory tests.

A patient can be declared brain dead only when the following conditions occur:

  • All the clinical criteria described above have been met.

  • No interfering medicines are being given. And, no reversible problem is found. In cases of infants and children, confirmation is done by one of the tests described above.

A dead brain has never been known to recover. Heart, lung, and kidney function can be maintained by artificial means almost indefinitely. Modern medicine and technology can maintain bodily functions (except brain function) for long periods of time. For this reason, in most cases, the caregiver will ask the next of kin about organ donation. This discussion occurs at a difficult time, but it is important. Your caregiver will discuss this topic in a sensitive and caring manner.