Cerebral Hypoxia (Brain Hypoxia)

Cerebral Hypoxia (Brain Hypoxia) develops when our brain receives less oxygen than required to sustain its metabolic requirements.

Among all cells in our body, the brain cells are most sensitive to the oxygen deprivation.

Five minutes without oxygen is enough for the brain cell to start dying. Cerebral Hypoxia that lasts for that or longer time can cause seizures, coma or even brain death.

Diminished oxygen supply to the brain may produce significant cognitive, physical and emotional impairments.

As a result, a hypoxic injury can have a profound impact, in terms of functional deficits, cost involved in treatment and the disruption it can have on people’s lives and that of their families.

Representing only 2-3% of an adult’s body mass, the brain receives 20% of the cardiac output and accounts for about one fourth of overall resting oxygen consumption. The brain is one of the most oxygen-sensitive organs of the body, and it is not surprising that neurologic dysfunction is a prominent manifestation of hypoxia. Neuropsychiatric manifestations of chronic hypoxia can be a major source of morbidity in patients with COPD.²⁶⁰

Cerebral vascular resistance is prominently affected by acute hypoxia and increases when PaO₂ falls below 50-60 mm Hg. However, with continued hypoxia, adaptation occurs, and overall cerebral blood flow in hypoxemic patients with COPD is normal. The brain is very sensitive to changes in perfusion, and effects of hypoxia on the brain are more likely to be due to decreased perfusion than to hypoxemia.²⁶⁰

Cerebral Hypoxia Symptoms And Causes

Extremely acute cases of brain hypoxia result in a state of complete unawareness and unresponsiveness with abolition of the brain stem reflexes including pupilary response to light and breathing reflex.

Among conditions that can lead to cerebral hypoxia (brain hypoxia) are: stroke, heart attack, hypotension, birth injury, aortic valve deficiency, compression of the trachea, general anesthesia, and other diseases which paralyze respiratory muscles.

Inadequate blood supply to the brain is a major cause of Ischemic hypoxia (stagnant hypoxia). Oxygen deficiency may not always be evident and obvious; therefore people should be aware of symptoms of hypoxia and take immediate corrective measures, especially patients who are at risk of developing oxygen deficiency.

Understanding the underlying cause of the hypoxia determines the hypoxia treatment which in emergency situations includes life-support measures like mechanical ventilation, blood infusions, medications to support heart rate blood pressure.

No need to mention that awareness of hypoxia symptoms is crucial, especially in cases of brain hypoxia / ischemic hypoxia, because it is a medical emergency and every moment is critical to a meaningful survival.

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Complications After Severe Cases Of Brain Hypoxia

Complications after severe cases of brain hypoxia may include a prolonged vegetative state, e.g. basic life functions such as breathing, blood pressure, sleep and wake cycle. Eye opening may be preserved, but the patient is not alert and does not respond to surroundings. Some patients suffering severe cases of cerebral hypoxia may survive about a year, some may survive longer. Time of survival partly depends on how much care is taken to prevent a complex of other problems. Major complications may include:

• Infections, e.g. Pneumonia
• Vein Thrombosis
• Bed Sores
• Improper Nutrition

Hyperbaric oxygen (HBO₂) significantly increases the oxygen diffusion driving force, thus increasing oxygen availability to tissues. This helps to correct negative effects of hypoxia and restore normal tissue oxygenation.

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