Is the patient alive or not? How brain death is determined

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When a patient in a deep coma is treated in the intensive care unit, artificial respiration is usually also required. Because in most cases his own respiratory drive is no longer sufficient to transport enough oxygen into the lungs and thus into the body. In addition, he often can no longer cough and swallow, so that without artificial respiration saliva would run into his lungs and lead to severe inflammation.

By: Moritz Pompl

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Precisely about preserved residual functions, such as respiratory drive or cough reflex, doctors like Dr. Stefanie Forderreuther during the neurological examination of the patient judge. Again and again, the brain functions of patients are examined, because only in this way can one say to what extent a patient’s condition is improving or worsening. During the neurological examination, various reflexes of the so-called cranial nerves, which are responsible for the pupils, for example, are tested among other things. The pupils normally contract when a bright lamp is shone into the patient’s eyes. If this pupillary reflex no longer functions, this is one of many indications that the pressure inside the skull is critically elevated and a failure of brain functions could develop.

"Patients in whom the cranial nerve reflexes no longer function have moderately wide to very wide, light-rigid pupils. Illumination with strong light sources no longer causes the pupil to contract. Patients also no longer blink when the cornea of the eye is touched. We also test reflex eye movements. This is because the eye muscles are connected to our center of equilibrium and normally show certain movements when the head is moved. We check whether the patient reacts to a pain stimulus, whether the gag reflex and the cough reflex are present. And then we also test whether the respiratory drive has ceased."

PD Dr. Stefanie Forderreuther, Neurological Consultation Service, LMU Clinic, Munich, Germany

Are there any influencing factors that simulate brain death?

The diagnosis "brain death However, this is by no means the end of the story. First of all, the conditions must be right. This means that Stefanie Forderreuther needs to know for her assessment: Are there any influencing factors that could obscure the neurological examination findings and feign the symptoms of brain death? This may be due to medication given to the patient to treat intracranial pressure, or to peculiarities in the patient’s metabolism, such as severely elevated blood sugar.

Diagnosis by second physician

In addition, for the diagnosis of brain death Always have a second physician verify that the requirements for a safe assessment of brain function are met, examine the patient, and independently come to the same conclusion. Both doctors must have nothing to do with a possible, later organ donation. They must have years of professional experience in the intensive care unit and be specially trained. One of the two examiners must be a specialist in neurology or neurosurgery; in the case of children, a pediatrician or neuropediatrician is required.

Technical devices only in exceptional cases

For the diagnosis of "irreversible loss of brain function the clinical examination at the patient’s bedside is usually sufficient. In some cases, however, technical devices are also used to consolidate the diagnosis – for example, if the original accident or trigger primarily damaged the brain stem. Then the doctors have to prove the failure of the cerebrum with the help of apparatus: An electroencephalogram (EEG) can be derived, which shows brain waves in a living person but no longer shows curves in a dead person. Or a blood circulation examination of the brain can be carried out – in the case of brain death no blood circulation would be detected any more.

Evidence of irreversibility

But even after clinical examination and evaluation, the diagnosis is not yet established. Finally, the last step is to prove that the clinical symptoms of the loss of brain function are irreversible, i.e., permanent. When proving irreversibility, the investigators must take into account the age of the patient and the location of the damage in the brain.

"For the final diagnosis, it is crucial to prove that the patient is unable to recover. In this case, there are again specific guidelines on how to proceed. These are based on what age the patient is and what type of brain damage is present."

PD Dr. Stefanie Forderreuther, Neurological Consultation Service, LMU Munich Hospital

For the diagnosis of "irreversible loss of brain function" it is usually sufficient if both examiners examine the patient clinically and, in a second examination at a different time, are again unable to detect any brain functions. The second examination takes place twelve to 72 hours after the first, depending on the type of brain damage – it must also be performed independently by two specialists. Alternatively, an additional apparative procedure may be used to supplement the clinical examination to shorten the 12-72 hour observation period.

In some cases, technical equipment must be used for the final diagnosis – for example, if the original accident or trigger primarily damaged the brainstem. Then doctors have to prove the failure of the cerebrum with the help of apparatus: An electroencephalogram (EEG, brain waveform) can be derived, which shows brain waves in a living person but no longer shows any spikes in a dead person. Or a blood flow examination of the brain can be carried out – in the case of brain death no blood flow would be detected any more.

If there is any doubt, or if the two specialists even disagree in their assessment, then death is not established and the patient continues to receive treatment. So far no single case is well-known, in which a patient diagnosed after the prescribed guidelines as brain dead would have recovered also only partially – the brain death proof is just as safe as obvious death signs, which some from the "crime scene" knows, for instance death marks or the corpse rigidity.

The body can still show reflexes

As long as intensive care is provided and doctors maintain circulation and breathing artificially, a brain-dead person looks as if he or she is still alive: his or her chest rises and falls due to artificial respiration, the skin is rosy and warm, the kidneys still excrete urine, and even wounds can still heal. In addition, if spinal cord function is preserved, the body may respond with reflexes – even though brain functions have ceased.

"The activity of the spinal cord and peripheral nerves may be preserved because the damage has affected the brain. Reflex-like movements may occur, which are naturally disconcerting and cause someone who is unfamiliar with the matter to have doubts. The rare Lazarus phenomenon is one of the reflexes that are mentioned again and again. The name Lazarus reflex describes a complex movement in which the patient reacts to a painful stimulus at the sternum with a bending movement of the arms, giving the impression that he wants to push the examiner’s hand away. At the same time, the head turns a little to the side. Unfortunately, it always gives the impression of a directed reaction – as with a living person. Thereby the reflex proceeds secured from the spinal cord. The examining physicians must therefore also have the expertise to differentiate: What is brain activity and what is not."

PD Dr. Stefanie Forderreuther, Neurological Consultation Service, LMU Clinic Munich

Complex movement patterns emanating from the spinal cord alone have been known for a long time. First descriptions can be found in reports about people who were beheaded or hanged. Since the spinal cord is largely under the control of the brain, certain reflexes may be particularly apparent when brain functions have ceased. As macabre as it may sound, in fact the permanent loss of brain function is equivalent to an internal decapitation. The fact that patients do not recover even after such an "internal decapitation" has been followed by the US neurologist Alan Shewmon: He has collected cases of patients who had been diagnosed with brain death. After brain death, the relatives of the patients insisted on continuing the care of the deceased at home and providing them with intensive medical care, sometimes for months or years. None of these patients ever recovered. In individual cases, an autopsy was performed later on. It showed that there were no nerve cells left inside the skull, only calcified connective tissue – in other words, nothing that remotely resembled a brain anymore. It had completely decomposed, although the rest of the body continued to function artificially at the same time.

The relatives can witness the diagnosis

To make it easier to say goodbye and to better understand the diagnosis of "brain death," Stefanie Forderreuther offers the relatives the opportunity to be present during the examination. She can then also explain the various peripheral reflexes that the patient may still be showing.

"For the relatives it is often a great help to have observed the tests themselves. They can then much more easily understand why we are talking about the death that has occurred. In addition, the relatives then also have the certainty that they accompanied the patient until death and stood by him. Once we have established death, it is clear that there is no way back. This is an essential, quite decisive difference to a prognostic assessment. Without the exact examination, a certain uncertainty may remain for one or the other: Could the doctor not be mistaken after all?? Doesn’t my husband, my sister, my mother perhaps still have a chance?? Most people can very well understand that without a brain, one no longer exists as a physical-mental entity and thus has died as a human individual. If you have ever seen such a patient, the staring eyes with these wide pupils that look through you, then it has nothing to do with the personal look that you know from a familiar person."

PD Dr. Stefanie Forderreuther, Neurological Consultation Service, LMU Clinic Munich

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