Difference between a coma and brain death

A coma is caused by a part of the brain functions failing or working less well (brain dysfunction). Coma is not the same as brain death. In a coma, there is still minimal electrical activity and metabolism in the brain. If someone is brain dead, there is no more brain activity, not even in the brain stem or the medulla oblongata.

 

Definition of brain death
Brain death is defined as: the complete and irreversible loss of the functions of the brain, brain stem and medulla oblongata.

 

Brain Death Protocol
Several tests will be performed that are legally established in the Netherlands in the Dutch brain death protocol to determine when someone is brain dead.

 

Brief explanation: Several doctors test the reflexes:

• by shining a light into the patient's pupils, among other things
  
• by wiping a cotton swab over the eye
  
• by squirting some ice water into the ear

 

Extensive explanation: In order to speak of brain death, during the clinical-neurological examination there must be:
1. absence of consciousness, evident from the absence of reactions to (pain) stimuli, as recorded in the Glasgow Coma Scale (GCS) for adults and in the Pediatric Glasgow Coma Scale (PGCS) for
children younger than 6 years.

2. absence of brainstem reflexes, namely:

• no pupillary reactions to light.
  
• no corneal reflexes (a corneal reflex is the involuntary closing of the eyelids when the cornea is touched.)
  
• no reactions to vestibular stimuli:
  
  • absent oculocephalic reflex = is a reflexive eye movement. For example, if the head is moved to the right, the eyes normally move to the left and vice versa.
    
  • absent oculovestibular reactions = If cold water is sprayed into the ear (provided there is no damage to the eardrum) they normally react with a tendency to move towards the tested ear, i.e. where the water was injected. Cold water in both ears should cause a downward deviation of the eyes, and warm water should cause an upward deviation.
    
• no cough reflex.
  

3. indication(s) of the absence of spontaneous breathing.

 

If a patient does respond to one of these tests, there is no brain death.

 

Additional diagnostics are performed.
First, the function or blood flow of the cerebrum is examined:

• for example, with an EEG (electroencephalogram), to determine whether there is electrical brain activity
  
• with a Transcranial Doppler examination (TCD) to assess the presence of cerebral blood flow
  
• by means of a CT angiography (CTA) scan to assess the presence of cerebral blood flow
  
• an apnea test is performed
  

During an apnea test, the breathing reflex is tested by briefly disconnecting the ventilator. If breathing does not start automatically after a while, brain death is definitively determined.

 

This is also the legally official moment of death.

 

Read all information of the Dutch government on this subject at

https://wetten.overheid.nl/BWBR0008776/2017-06-01

 

Information about laws on brain death in the United States can be found here.

 

Information about laws on brain death in the UK can be found here.