CIA Copy of National Institute of Health Article: NINDS Cerebral Hypoxia Information Page

C 0 5 9 514 2 0 Hypoxia Information Page http .//www,ninds.nih.gov/health_and medical/disorders....
NINDS Cerebral Hypoxia Information Page
Synonym(s): Hypoxia, Anoxia
Reviewed 05-06-2003
Table of Contents (click to jump to sections)
What is Cerebral Hypoxia?
Is there any treatment?
What is the prognosis?
What research is being done?
Organizations
What is Cerebral Hypoxia?
Cerebral hypoxia refers to a condition in which there is a decrease of oxygen
supply to the brain even though there is adequate blood flow. Drowning, strangling,
choking, suffocation, cardiac arrest, head trauma, carbon monoxide poisoning, and
complications of general anesthesia can create conditions that can lead to
cerebral hypoxia. Symptoms of mild cerebral hypoxia include inattentiveness, poor
judgment, memory loss, and a decrease in motor coordination. Brain cells are
extremely sensitive to oxygen deprivation and can begin to die within five minutes
after oxygen supply has been cut off. When hypoxia lasts for longer periods of
time, it can cause coma, seizures, and even brain death. In brain death, basic life
functions such as breathing, blood pressure, and cardiac function are preserved,
but there is no consciousness or response to the world around
Is there any treatment?
Treatment depends on the underlying cause of the hypoxia, but basic life-support
systems have to be put in place: mechanical ventilation to secure the airway;
fluids, blood products, or medications to support blood pressure and heart rate;
and medications to suppress seizures.
What is the prognosis?
Recovery depends on how long the brain has been deprived of oxygen and how
much brain damage has occurred, although carbon monoxide poisoning can
cause brain damage days to weeks after the event. Most people who make a full
recovery have only been briefly unconscious. The longer someone is unconscious,
the higher the chances of death or brain death and the lower the chances of a
meaningful recovery. During recovery, psychological and neurological
abnormalities such as amnesia, personality regression, hallucinations, memory
loss, and muscle spasms and twitches may appear, persist, and then resolve.
What research is being done?
The NINDS supports and conducts studies aimed at understanding neurological
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Hypoxia
(from an Air Force manual)
Hypoxia
Hypoxia is a state of oxygen deficiency in the body which is sufficient to cause an
impairment of function. Hypoxia is caused by the reduction in partial pressure of
oxygen, inadequate oxygen transport, or the inability of the tissues to use oxygen.
In brief, being drunk is kind of the same as being exposed to high altitude. In both
cases, oxygen to your brain and muscles is reduced.
Hypoxic Hypoxia is a reduction in the amount of oxygen passing into the blood.
It is caused by a reduction in oxygen pressure in the lungs, by a reduced gas
exchange area, exposure to high altitude, or by lung disease. [This is the hypoxia
that is a hazard to aviators.]
Hypemic Hypoxia is defined as a reduction in the oxygen carrying capacity of the
blood. It is caused by a reduction in the amount of hemoglobin in the blood or a
reduced number of red blood cells. A reduction in the oxygen transport capacity of
the blood occurs through blood donation, hemorrhage, or anemia. A reduction in
the oxygen carrying capacity of the_blood occurs through drugs, chemicals,- or
carbon monoxide. [This hypoxia usually experienced by smokers.]
Stagnant Hypoxia is an oxygen deficiency due to poor circulation of the blood or
poor blood flow. Examples of this condition are high "G" forces, prolonged sitting
in one position or hanging in a harness, cold temperatures, and positive pressure
breathing. [This hypoxia usually experienced when sitting for hours in a boring
class.]
Histotoxic Hypoxia is defined as the inability of the tissues to use oxygen,
Examples are carbon monoxide and cyanide poisoning. Certain narcotics, chewing
tobacco, and alcohol will prevent oxygen use by the tissues. [This hypoxia usually
experienced after drinking too much.]
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