Page "Coma" Paragraph 6

The second most common cause of coma, which makes up about 25 % of comatose patients, occurs from lack of oxygen, generally resulting from cardiac arrest.

The Central Nervous System ( CNS ) requires a great deal of oxygen for its neurons.

Oxygen deprivation in the brain, also known as hypoxia, causes neuronal extracellular sodium and calcium to decrease and intracellular calcium to increase, which harms neuron communication.

Lack of oxygen in the brain also causes ATP exhaustion and cellular breakdown from cytoskeleton damage and nitric oxide production.