The first case – plant life

If only the blood supply to the cerebral cortex is disrupted, all of the patient’s senses and movements are lost, but breathing and other items originating from the brainstem remain. This condition almost always follows coma. Although the person appears awake (eyes open), does not need an artificial respiratory device. In this case the patient has a series of involuntary movements of limbs and has no mental or cognitive function. These patients may remain in this condition for years and then return to life or die.

The second case – locked man

If only the blood supply to the brainstem is disrupted and the cerebral cortex remains intact, the patient would have no movement (except for some number of eye movements whose fibers extend from the outside of the brainstem to the cerebral cortex) and no breath. But this patient has the ability of complete perception whom can answer yes or no questions with eye movements. Due to their inability to breathe, these patients must use an artificial respiratory device and may remain in this condition for years. The above patients are rarely reversible and generally die from infectious complications.

The third condition – brain death

The blood supply to both parts of the cerebral cortex and the brainstem is disrupted, and we are faced with a patient whom has no movement or perception. In these cases, brain death occurs and the brain tissue is destroyed, taking on a shapeless, irreversible and a yogurt-like state. It should be noted that after brain death, as time goes on, the organs will be destroyed, in other words, they will rot and will not be usable, one by one.

1- CT Scan of, Right: Healthy Brain, Left: Brain death

What is the difference between brain death and coma?

Coma is a type of brain dysfunction in which a person experiences a sharp decrease in the level of consciousness and does not respond to any of the stimuli around him. In this case, the cell structure is not destroyed and only the function of these cells is disrupted. This dysfunction may recur after a long time, and the patient may become conscious.

However, in brain death, there will be no return due to cell destruction. The brain-dead person looks like a deep coma patient.

What are the common causes of brain death?

• Driving accidents
• Severe blow to the head
• Falling from a height
• Drowning in water
• Poisoning
• Internal bleeding of the brain as well as stroke.

How do the above factors lead to brain death?

The four main arteries that run from the neck to the skull are responsible for supplying blood to the brain and brainstem. Some cases, such as trauma to the head, cerebral hemorrhage caused by rupture of cerebral arteries, brain tumors, etc., cause an increase in intracranial pressure, and due to the non-dilatability of the skull bones, high pressure causes the intracranial arteries to close.

As mentioned earlier, this event leads to the cessation of blood supply to the brain cells, and all the cells in the brain and brainstem are destroyed and the brain death occurs.

Sometimes, due to the interruption of oxygen delivery to the brain, for example, suffocation or cardiac arrest, without interruption of blood supply, all brain cells and brainstems are destroyed and brain death occurs.

Do the heartbeat and respiration continue after brain death?

Because the respiratory center is located in the brainstem, breathing is immediately interrupted by brain death, but the heart, which has an automatic battery, even if the head is cut off or the heart is removed and placed in a physiological serum would continue beating for a few minutes or a few hours to a few days if oxygen is delivered.

If the patient is connected to an artificial respiratory device shortly after an accident that results in brain death (a few minutes), the blood supply to the organs and viscera can be restored by continuing the heartbeat (by delivering oxygen via an artificial respiratory device). This will keep the organs for a short time (from one day to 14 days) until, the patient’s family agreed to donate organs and save several patient lives from certain death, and otherwise after this time cardiac arrest or normal death is a complication. Breathing in people with brain death continues by the device, and the person in brain death state does not breathe.

How is brain death diagnosed?

Immediately after identifying a suspected brain death case, an organ donation coordinator (who is the primary examiner) from the organ donation unit would visit the patient.

At first, the patient’s history and documents are carefully examined, then the twelve cranial nerves function is examined (all examinations related to the cortex and brainstem), and a brain scan will be taken.

What do brain death examinations show?

• Lack of breathing (breathing is established by an artificial respiratory device)
• Feeling no pain
• No pupils respond to light (the pupils do not narrow )
• Do not blink if the cornea is stimulated with a tissue or a piece of thread
• By stimulating brain death patient, there are sometimes movements in the muscles of the arms and legs which called spinal reflexes. The above movements do not rule out brain death because they are caused by the spinal cord, not the brain.

What methods can be used for definitive confirmation in case of doubting about brain death?

Advanced brain imaging techniques such as computed tomography (CT) scanning of the brain (TCD), isotope scanning, and cerebral vascular angiography are used to confirm the absence of any blood supply to the brain

Has there been any brain death that has improved?
No, a brain dead person would not recover and return to life. In case of hearing about recovering a dead brain person, be sure that it has not been a brain death basically.

Does a brain dead patient feel pain?
No. After the death of the brain, there will be no sense of pain or sadness in humans.

Is it possible to opine brain death from patient appearance?
No, a brain death patient is just like someone who is in a deep sleep. Lungs are filled with air with the help of a ventilator, heart is pounding with oxygen, and even the skin is warm and in pink color.