What is hypoxia and can it really kill you

What is hypoxia

Hypoxia is conditionb. S. Bhuta, F. Alghula, I. Berim. Hypoxia/StatPearlsin which the tissues of the body do not receive enough oxygen to function normally.

This concept should not be confused with hypoxemiaHypoxemia / Cleveland Clinic - Lack of oxygen in the blood. These conditions often occur in pairs, but can also occur separately.

For example, at high altitudes, there may be little oxygen in the blood, but the body compensates for this with a series of adaptations, and hypoxia will not occur - the tissues will have enough O₂ for normal operation.

The opposite can also happen if oxygen saturation is normal - there is no hypoxemia - but the body for some reason cannot use it.

Why does hypoxia occur?

There are many reasons why maybeb. S. Bhuta, F. Alghula, I. Berim. Hypoxia/StatPearls this condition occurs:

1. Insufficient amount of oxygen in the air or its pressure is too low. This can happen, for example, at high altitudes.

2. Lack of hemoglobin. This iron-containing protein binds to red blood cells - erythrocytes and carries oxygen. A decrease in its level is called anemia, and it can occur for a number of reasons: due to genetic abnormalities, chemical poisoning, or a lack of iron in the diet.

3. Impaired gas exchange in the lungs. To hemoglobin could contact with oxygen, the blood in the capillaries must interact with the alveoli of the lungs - vine-like formations through which gas exchange occurs. If blood flow to the lungs is limited, little air enters the alveoli, or the gas is poorly transported through the tissues, hypoxia occurs. This can happen with bronchitis, asthma, emphysema and other diseases, as well as if the airways are blocked.

4. Violation of the cardiovascular system. Heart problems can prevent blood from reaching the tissues of the body, even if there is enough oxygen in it. The case when there is no hypoxemia, but hypoxia occurs.

5. Inability of tissues to utilize oxygen. This can happen, for example, with cyanide poisoning, which inhibits the enzyme cytochrome-C-oxidase in the mitochondria of cells, blocking the use of oxygen for energy production.

How to understand that hypoxia has occurred

There are several ways to determine that there are problems with oxygen in the body.

Feeling and appearance

Hypoxia can manifest itself in different ways depending on the causes. For example, if there is not enough oxygen due to a lung infection, a cough and fever will appear; in a heart attack, swelling of the legs and nighttime shortness of breath may occur.

At the same time, there are common symptoms1. b. S. Bhuta, F. Alghula, I. Berim. Hypoxia/StatPearls
2. Hypoxemia / Cleveland Clinic, which may indicate a lack of oxygen:

• headache;
• dyspnea;
• heart palpitations;
• cough;
• confusion;
• fatigue and weakness;
• dizziness;
• bluish tint to the skin, nails and lips.

Chronic hypoxia manifests itself more mildly. Often the only symptom is shortness of breath during activity.

Using a pulse oximeter

Pulse oximeters are portable devices that can check blood oxygen saturation. Sold as separate inexpensive gadgets that can be hooked on your finger, as well as fitness bracelets and watches with a built-in SaO measurement function₂.

The principle of their work foundedE. D. Chan, M. M. Chane, M. M. Chan. Pulse oximetry: Understanding its basic principles facilitates appreciation of its limitations / Respiratory Medicine on the fact that oxyhemoglobin - a protein associated with oxygen - and "empty" deoxyhemoglobin absorb infrared light in different ways.

The IR sensor of the device shines through a person’s finger or wrist, catches the returned rays on a light-sensitive matrix, and then calculates the percentage of oxyhemoglobin in the blood. The norm is considered to be 95-98%.

At the same time in one researchE. D. Chan, M. M. Chane, M. M. Chan. Pulse oximetry: Understanding its basic principles facilitates appreciation of its limitations / Respiratory Medicine noted that pulse oximeters can be wrong in different forms anemiawhen the blood contains many non-functional forms of hemoglobin, and also does not show problems with ventilation of the lungs.

So if you notice any of the symptoms of hypoxia, it is better not to delay the visit to the therapist, even if SpO₂ fine. The doctor will check the condition of the lungs and heart and may use more accurate tests to determine blood saturation.

How dangerous is hypoxia

It all depends on how severe hypoxia is, as well as on the reasons that caused this condition.

For example, a lack of oxygen at high altitudes can ensureM. F. Essop. Cardiac metabolic adaptations in response to chronic hypoxia / The Journal of Physiology a number of positive adaptations of the body: increase the amount of hemoglobin and improve the functioning of mitochondria - cell organelles responsible for energy production.

At the same time, hypoxia caused, for example, by pulmonary fibrosis or chemical poisoning, will not lead to good consequences and requires treatment.

The greatest danger is acute and severe cerebral hypoxia. brain cells are very sensitiveCerebral Hypoxia / Cleveland Clinic to a lack of oxygen, and in its absence they begin to die within five minutes.

Therefore, cerebral hypoxia in a short time can end in coma, death or permanent brain damage and loss of important functions.

Here are a few signs of this dangerous condition:

• confusion and slurred speech;
• rapid or difficult breathing, respiratory arrest;
• blue or gray skin tone and lips;
• dilated pupils, convulsions, convulsions;
• lack of response to requests and appeals.

If you notice something like this, call an ambulance immediately. The sooner a person is helped, the less the risk of death and serious consequences.