Brain Injury by a lack of oxygen /oxygen deficiency


Brain injury due to oxygen deficiency; for example, after resuscitation, cardiac arrest or respiratory arrest, drowning, suffocation, choking, prolonged seizure, (smoke) poisoning.



The brain requires a constant flow of oxygen to function normally. A hypoxic-anoxic injury, also known as HAI, occurs when that flow is disrupted, essentially starving the brain and preventing it from performing vital biochemical processes. Hypoxic refers to a partial lack of oxygen; anoxic means a total lack. In general, the more complete the deprivation, the more severe the harm to the brain and the greater the consequences.

There are major differences in the severity of the impact varies by situation and varies from person to person. Some have mild residual symptoms, and others will no longer have a sense of life.


  • Hypoxia: A reduction or inadequate flow of oxygen to the brain. Causes may include heart attack or near drowning.


  • Anoxia: A total lack of oxygen to the brain. Causes may include heart attack or near drowning.

Three minutes of OXYGEN emergency supply

The heart pumps oxygenated blood throughout the body. Two pairs of large arteries branch throughout the brain. They bring a continuous flow of oxygen and glucose.

The brains have an emergency energy supply for about three minutes. In a cardiac arrest, the brains run out of their emergency power supply of oxygen quickly, if not is started fast with resuscitation. Causing damage everywhere and memory problems.

If someone has had a lack of oxygen, there is not one particular place in the brains, but everywhere where normally blood flows. This is called diffuse brain damage = damage anywhere in the brain.

In particular, the temporal lobe (at the temples) is sensitive to oxygen deficiency which is also where the memory is situated.

A lack of oxygen from three to nine minutes can result in irreversible brain damage! In case of a cardiac arrest a CPR (Cardiopulmonary resuscitation) is best started within two minutes. 

An ischemic stroke occurs when a part of the brains die because of a blocked arteria which lead to a partial lack of oxygen:

Oxygen deficiency may occur after:

  • CPR (Cardiopulmonary resuscitation)

  • drowning

  • suffocation

  • choking

  • strangulation

  • status epilepticus (prolonged seizure)

  • intoxication

  • smoke inhalation



Consequences may be:

  • (severe) memory problems

  • spasticity

  • incontinence

  • changes in personality

  • disorientation in place, person and time

  • difficulty walking

  • speech difficulties


Global cerebral ischemia

Global cerebral ischemia occurs when blood flow to the brain is stopped or reduced. This is usually triggered by cardiac arrest. If adequate circulation is restored within a short period of time, symptoms may be brief.

However, if a large amount of time passes before restoration, brain damage can be permanent. While reperfusion may be essential to protecting as much brain tissue as possible, it may also lead to reperfusion injury or damage that results from the restoration of blood supply to ischemic tissue.

The symptoms of cerebral ischemia include:

  • blindness in one eye

  • weakness in one arm or leg

  • weakness in one entire side of the body

  • dizziness, vertigo, double vision

  • weakness on both sides of the body

  • difficulty speaking

  • slurred speech
  • loss of coordination

The symptoms of cerebral ischemia range from mild to severe. Symptoms can last from a few seconds to a few minutes or for extended periods of time. If the brain becomes damaged irreversibly and tissue death occurs, the symptoms may be permanent

Cerebral ischemia is linked to many diseases or irregularities. Patients with compressed blood vessels, plaque buildup in the arteries, blood clots, very low blood pressure as a result of heart attack, congenital heart defects and even sickle cell anemia have a higher tendency to cerebral ischemia in comparison to their healthy counterparts.


Brain damage after cardiac arrest
It is estimated that eight out of ten 'successful' resuscitations (where the person remains alive), the patient becomes comatose and eventuelly has brain injury. The sad fact is that a person in that case enters the hospital as a heart patient and leaves as a brain injury patient.

The question then emerges: what is called a 'successful' CPR? Prognosis depends on conditions such as temperature (heat or cold), speed of onset of CPR, where is the person in cardiac arrest itself. Does it happen in a remote area or is the person already in a hospital?
More often people are offered a cognitive screening after a cardiac arrest.

Because in particular the memory is damaged after a lack of oxygen, it will be the first symptom to be noticed, but there can be more invisible disabilities. Ask for a neuropsychological examination and/or cognitive rehabilitation if you have any doubt of cognitive problems. Read more....on cognitive problems.



Neurological outcomes after cardiac arrest:

Neurological outcomes among survivors cover a broad spectrum ranging from complete recovery to the vegetative state.

Patients who awake promptly after resuscitation provide a gratifying experience to their physicians and present no problem in prognosis.

However, neurologists are often asked to see patients in coma following cardiac arrest to help predict the degree of eventual recovery and to advise the family and plan future therapy.

Cardiac arrest may be thought of as causing both 'metabolic' and 'structural' damage to the central nervous system. Patients with brief episodes of systemic circulatory arrest who suffer milder degrees of cerebral anoxia-ischemia demonstrate the clinical features of a reversible 'metabolic encephalopathy'.

Coma if present, lasts only a few hours 12 at most. On awakening, these patients demonstrate few 'focal motor, sensory or intellectual deficits but may be transiently confused or amnestic for hours to days. Recovery is rapid and complete.

By contrast, patients with more severe systemic anoxia-ischemia suffer structural damage to specific areas of the brain as if they had a stroke. The vulnerable areas of the nervous system include cerebral cortex, hippocampi, the cerebellum, the basal ganglia, and sometimes the spinal cord. Patients in this group are usually in coma for at least 12 hours and on awakening manifest lasting focal or multifocal
motor, sensory, and intellectual deficits. Recovery is often incomplete and slow, on the order of weeks to months.

Some of these patients are able in time to lead an independent existence at home despite residual neurological deficits (Moderate Disability), while others, severely disabled and dependent, remain in nursing homes (Severe Disability). Others with more widespread destruction of brain may remain hospitalized in a state of wakefulness without awareness (Vegetative State) or die a neurological death (Brain Death).


Brain damage after cardiac arrest.pdf
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