Oxygen toxicity and its toxic effect

Without oxygen life would be impossible. It is a colorless gas, odorless. Its concentration in the air does not exceed 21%. But in some cases it can be a real poison to the human body. It is therefore important to know under what circumstances is oxygen toxicity and how to deal with it.

How does the poisoning

Oxygen toxicity is called hyperoxia. It occurs after inhalation of the gas mixture, which includes oxygen. The composition should be under pressure. Even pure oxygen if it is in a discharged state, poison cannot. High blood pressure – a prerequisite for the development of poisoning.

This problem can occur in divers, astronauts, pilots, as well as people undergoing treatment in the chamber in violation of the rules of procedure.

The causes of poisoning

Among the main reasons for oxygen toxicity are the following:

  1. During the descent under the water hyperoxia occurs after exceeding the acceptable depth of immersion, the use of respiratory formulations with a high content of oxygen, damage to the work coloradoboulder mechanism, improper operation of the washing unit of the device.
  2. The excess of timing of oxygen decompression. Intoxication can occur after 3 hours.
  3. The excess concentration of oxygen in the gas mixture for the chamber.
  4. The failure of an oxygen mask for pilots of high-speed aircraft.

In order to avoid serious health consequences, it is necessary to take timely measures.


Experts identify three main toxic forms of hyperoxia:

  1. Vascular. Considered the most dangerous to life. It occurs when the highest pressure gas composition. Accompanied by severe vasodilation, a rapid decrease in blood pressure. There is numbness of the fingers, dizziness, and headache. There are often hemorrhages in the skin or mucous membranes. The pressure drop is fraught with disruption of the heart. In complex cases, there can be fatal.
  2. Convulsive. Appears if the pressure of the gas mixture is set at 3 bar. Is accompanied by abnormalities in the nervous system. Appear anomalies of vision, increased drowsiness, excessive sweating, pallor of the skin. With the growth of intoxication appear cramps, vomiting and loss of consciousness. If time does not take measures, may develop pulmonary edema. Convulsive form is commonly divided into three main stages: the precursors, the onset of a convulsive condition and the terminal:
  • At the stage of precursors show the initial signs of poisoning. It can last about half an hour. The higher the dosage of oxygen, the longer the stage. The first symptom of this stage becomes numbness, a sense of depression and fear. The heart rate and breathing increase. Before the second stage, the skin becomes excessively pale, man break through a cold sweat, involuntarily reduced facial muscles.
  • The second stage starts, convulsive seizures, which occur in the condition of loss of consciousness. The first attack usually lasts no more than 10 seconds. After that comes a period of relaxation. Then the attack is repeated again. If from oxygen exposure was too long, seizures are prolonged pauses between them are short. In the intervals between the convulsions observed rapid breathing and heartbeat, bulging of the eyeballs, involuntary urination and defecation.
  • At the last stage of convulsions stop, there is a disorder of respiratory activity. If time does not take measures, will stop breathing.

In order to prevent the onset of the third stage, you need to remove the source of poisoning.

  1. Pulmonary. Observed at sufficiently low pressure. It is characterized by defeat of respiratory ways and lungs. The initial signs of getting dry mouth, edema of the mucosa of the nasopharynx. After developing cough, burning sensation in chest area. If time does not start treatment, there is hemorrhage in the liver, brain, heart, intestines.

Depending on the form of the disease, measures are taken to first aid and developed by subsequent treatment.

What causes the poisoning

Increasing the concentration of oxygen in the blood leads to the fact that the amount of oxidized hemoglobin is much higher than the haemoglobin is restored. This provokes an arrest in the blood of carbon dioxide. This process is called hypercapnia. In this case, there are characteristic symptoms: severe headache, shortness of breath, fainting, redness of the skin of the face.

Intoxication leads to disruption of oxygen exchange in the tissues. As a result, releasing large quantities of free radicals. They have a destructive effect on cell membranes. Hyperoxia accelerates this process. Stand out highly toxic compounds that worsen the patient's condition in General.

The overabundance of oxygen in the body leads to serious violations of the transport of gases, the cells are damaged. And biochemicalchanges appear immediately after the poisoning. The presence of aggravating factors complicate the situation. Intoxication is more pronounced if the inhaled mixture is present neutral gas.


The toxic effect of oxygen is primarily manifested by blue discoloration of the extremities. If time does not take action, the degree of intoxication increases rapidly.

If the fabric got quite a bit of oxygen, there is oxygen intoxication. Characterized by the following symptoms:

  1. Dizziness.
  2. Appears a veil before the eyes.
  3. Consciousness becomes clouded.
  4. In the ears noise.

The patient's condition are similar to hyperventilating, that is too strong a breath.

Symptoms of oxygen toxicity appear fast enough. Among them particularly are:

  1. Blurred vision.
  2. The appearance of tinnitus.
  3. Bouts of nausea and vomiting.
  4. Unpleasant sensations in the limbs, the muscles of the face.
  5. Agitation, anxiety.
  6. Dizziness.
  7. The emergence of seizures.
  8. Decreases heart rate.
  9. Shortness of breath.
  10. The skin on the face become a Magenta tint.

These signs of poisoning may not occur completely. It all depends on the form of the disease and the severity of the condition.

What factors aggravate the situation

There are several factors that can cause degradation of the victim:

  1. Increased physical activity at the time of intoxication.
  2. Hypothermia or overheating of the body.
  3. Increased sensitivity of the organism.
  4. The content in the inhaled mixture of contaminants, for example carbon dioxide.
  5. The accumulation in the body carbon dioxide.

In the presence of such aggravating circumstances first aid measures victim should be taken immediately.

Event first aid

You first need to eliminate the source of danger. If intoxication came when submerged under water, he must quickly raise the surface. Among the measures of first aid are the following:

  1. If the patient has lost consciousness, it is necessary to take all measures to bring it back to life. Especially if the incident occurred under water, because of the probability of drowning. Experienced divers use proven methods. They release the victim in the face with a jet of air with a high content of oxygen. Often it brings positive result.
  2. Upon the occurrence of cramps try to avoid human injury. Protect his head. Record of the patient is impossible. Decompression is also unacceptable.
  3. If you found signs of vascular forms of poisoning, for days after the intoxication the patient must be in a dark warm room with good ventilation. If symptoms persist, you should immediately contact your doctor.
  4. Place the victim half-sitting. On the upper and lower extremities attach the harnesses. Leave for 1.5 hours.
  5. In the absence of signs of serious intoxication, the patient must be just give a good night's sleep. Healthy sleeping will help to restore the body.

As a rule, the consequences of poisoning are a couple of days later. But the self is not engaged, it may be fraught with serious complications. Therefore, after rendering the victim first aid immediately, call an ambulance.


After taking all first aid measures, seek help from a doctor. A specialist will be able to diagnose the victim's condition and develop a treatment program.

In some cases after poisoning therapy with antibiotics. This is to avoid complications of an infectious nature. Medications shown and when the symptoms of pneumonia.

If there is severe damage to the lungs, it is first necessary to eliminate puffiness. For these purposes, use inhalation of different drugs.

If oxygen toxicity in the form of light, after the termination of seizures, the patient is prescribed analgesics. Then people should observe complete rest.

In the case when the convulsions do not stop for a long period of time or resume the attacks need to stop. For this purpose, special medications that are injected intramuscularly. To prevent damage to jaw or tongue during a seizure, it is necessary to put in the mouth of the victim with any object such as a spoon wrapped in cloth.

Sometimes there are complications of the cardiovascular system. In this case, is assigned to appropriate therapy.

Specific drugs and their dosage should be chosen solely by the attending physician after assessing the state of health of the victim. Self-medication in this case is unacceptable.

Timely competent therapy will help to quickly recover health and to avoid consequences.


Especially careful should be those who are constantly faced with gas mixtures, namely the divers. Observe the following precautions:

  1. Not to take on too much depth.
  2. To comply with allowable time in the water.
  3. Carefullyto monitor the quality of cylinders and their contents. Study the markings.
  4. Before each dive, carefully inspect and test all equipment.

Only compliance with such recommendations will help to avoid toxicity and to maintain health.

In some cases, oxygen is poisonous to humans. Therefore, it is necessary to observe all precautions and at the first sign of problems to take all possible measures.