For many of us, when we climb to a height, we catch our breath, and when we are in poorly ventilated rooms, we feel tired and lightly dizzy. This is due to a lack of oxygen for our organs. If in the above cases this is due to external factors, then sometimes a lack of oxygen occurs in the form of a disease. It can be of a different nature, severity and symptoms, sometimes it can reach serious consequences or death. This article discusses the main characteristics of the concept of hypoxia, the principles and classification of hypoxic conditions, as well as the main methods of treatment and prevention.
Definition
Hypoxia is a condition in which the body is deprived of oxygen supply at the tissue level. Hypoxia is classified as generalized, affecting the whole organism, or local, affecting certain organs. Although hypoxia is a disease of a pathological nature, various levels of arterial oxygen concentration are acceptable in the case of certain physical conditions, for example, when learning hypoventilation or active exercise.
Exogenous or hypoxic hypoxia is associated with elevations to greater heights, and this even causes a high-altitude illness in healthy people, leading to fatal consequences: pulmonary edema and acute cerebral cerebral edema. Hypoxia also occurs in healthy people when breathing mixtures of gases with a low oxygen concentration, for example, underwater diving while using closed rebreather systems that control the oxygen content in the supplied air. The artificially induced moderate state of hypoxia is used specifically during training at high altitudes to develop adaptation both at the systemic and cellular levels.
Hypoxia is a common complication in newborns resulting from premature birth. As the fetal lungs develop towards the end of the third trimester, premature babies are often born with underdeveloped lungs. Infants at risk of hypoxia are placed in incubators, which provide small organisms with oxygen and positive airway pressure.
Degree of hypoxia
There are several degrees of pathology:
- Easy. It appears during normal physical exertion.
- Moderate. The degree is manifested in chronic hypoxia in the usual state.
- Heavy. It manifests itself in an acute attack of hypoxia and can lead to coma.
- Critical Severe manifestation of hypoxia can be fatal.
Generalized hypoxia
In altitude sickness, when hypoxia develops less progressively, symptoms include:
- fatigue,
- numbness,
- tingling of limbs
- nausea and anoxia.
With severe hypoxia are observed:
- confusion of consciousness
- lack of orientation
- hallucinations
- behavioral changes
- drawing headaches
- severe shortness of breath
- pronounced tachycardia,
- pulmonary hypertension, leading to a slowed heart rate, low blood pressure, which leads to death.
Hypoxia is the result of impaired transport of O 2 to cells. In parallel, there is a decrease in the partial pressure of oxygen, a violation of gas exchange in the lungs, a decrease in hemoglobin level, changes in blood flow to the final tissue and problems with the respiratory rhythm.
Oxygen in the blood has a constant relationship with hemoglobin, so any intervention in this carrier molecule prevents the delivery of oxygen to the periphery. Hemoglobin increases the oxygen content in the blood by about 40 times. When hemoglobin’s ability to transport oxygen is impaired, a state of hypoxia occurs.
Ischemic hypoxia
Ischemia, which means insufficient blood flow to the tissues, also leads to hypoxia. This is called "ischemic hypoxia," causing an embolic state. This hypoxia causes a heart attack, which reduces overall blood flow, which leads to further damage to the tissues. Insufficient blood flow causes local hypoxia, such as gangrene, in people with diabetes.
Hypoxemic hypoxia
Hypoxemia is a hypoxic condition in which there is a lack of oxygen in the blood. Hypoxic hypoxia develops with disorders in the respiratory center. These include:
- respiratory alkalosis,
- bypass blood in the lungs
- diseases that interfere with the full functioning of the lungs, which leads to a mismatch of ventilation and perfusion (V / Q),
- pulmonary embolism
- partial changes in oxygen pressure in ambient air or lung alveoli.
It is also called exogenous, this type of hypoxia is due to the low oxygen content in the air. This species is found at elevated or lowered heights. Hypoxic hypoxia can be divided into hypobaric and normobaric. The first refers to cases when a person is exposed to low air pressure and low oxygen content. This happens in the mountains or on low-altitude aircraft, which fly without masks. The second refers to situations in which there is no change in pressure, but there is still little oxygen in the air. This happens in mines or other enclosed spaces.
Causes
The causes of hypoxic hypoxia can be quite diverse. Of the main ones, one can distinguish:
1) Discharged air at height. This is one of the most common causes of hypoxia, which is present even in healthy people.
2) Poor ventilation in enclosed spaces with a large number of people. One of the most common household causes of hypoxic hypoxia.
3) Being in rooms that have no connection with the outside world. These include various types of mines, wells, and also submarines.
4) Malfunction of the respiratory apparatus in conditions of severe gas contamination. For example, work in smoky rooms with a malfunctioning gas mask.
Symptoms
Symptoms and consequences of hypoxia depend on the body's ability to respond to oxygen deficiency, as well as on the degree of ongoing hypoxia. Among the most common symptoms are the appearance of shortness of breath, difficulty breathing, as well as dysfunction of some organs. It is also worth emphasizing that the nervous and cardiovascular system is most susceptible to hypoxia, which is characterized by rapid or decreased heart rate. In acute hypoxia, the functioning of one of the cerebral hemispheres is possible, which can lead to death or irreversible changes. If hypoxia is chronic, then it is characterized by the appearance of shortness of breath during various physical activities. Chronic fatigue may occur due to a lack of oxygen for all organs.
Types of hypoxic conditions
There are two varieties:
Hemoglobin is responsible for transporting oxygen throughout the body. Hemoglobin deficiency leads to anemia, which causes anemic hypoxia. Lack of iron in the body is the most common cause of anemia. Since iron is involved in the formation of hemoglobin, it will be produced in smaller quantities due to the lack of this trace element, which is either small in the body or poorly absorbed. Anemia, as a rule, is a chronic process that over time is compensated by an increased level of red blood cells through increased erythropoietin.
Severe hypoxic exogenous hypoxia is characterized by increased heart rate and respiration, the occurrence of tachycardia, and the amount of blood passing through the heart also increases due to the fact that the bone marrow releases an additional portion of red blood cells into the blood stream to maintain a normal level of oxygen in the body. In an acute attack of hypoxic hypoxia, the body directs all the blood to the central organs, ignoring the secondary ones. In this case, if the attack is eliminated in a short period of time, then a person can keep his body normal. If the attack is not immediately eliminated, then you can be late with first aid and irreparable reactions will occur in the body, with a possible fatal outcome.
Chronic hypoxia
This degree of hypoxic hypoxia is characteristic during a period of serious illness, it takes a fairly long time. This is the main difference from acute hypoxia. With a long period, the body adapts to the conditions of oxygen deficiency and begins to receive oxygen for cells in new ways. In the lungs, the network of blood vessels increases, and the blood is supplied with additional hemoglobin. The heart is forced to distill huge volumes of blood and therefore increases in size. If in acute hypoxia after elimination of symptoms all organs return to their normal state, then in chronic hypoxia the body is rebuilt forever.
Histotoxic hypoxia
Histotoxic hypoxia occurs when the oxygen level in the cells meets the normal limits, but the cells cannot use it effectively, due to the oxidizing phosphorylation catalysts that do not fulfill their function. This happens with cyanide poisoning.
The effects of hypoxia
The effects of hypoxic hypoxia are very diverse. If the body’s cells lack oxygen, the electrons are converted to pyruvic acid during the fermentation of lactic acid. This temporary measure allows a small amount of energy to be released. The appearance of lactic acid (in tissues and blood) is an indicator of insufficient oxygenation of mitochondria, which can be caused by hypoxemia, poor blood circulation (for example, shock), or a combination thereof. A similar condition, having a long and severe form, leads to cell death. Pulmonary hypertension adversely affects survival during hypoxemia, to the extent that elevated mean pulmonary artery pressure rises. Chronic hypoxemia increases mortality in any disease severity.
Numerous studies in patients with hypoxemia have demonstrated a relationship between daily hours of oxygen use and survival. There is reason to believe that continuous 24-hour use of oxygen in patients with hypoxia would reduce the mortality rate. Oxygen concentrators are ideal for this purpose. They are easy to maintain and do not require significant energy costs. They are a constant source of oxygen and eliminate the costly transportation of oxygen cylinders. Climate-controlled rooms are equipped in offices and residential premises, in which temperature and humidity are kept constant. Oxygen in this system is always available.
Hypoxia treatment
Since hypoxia is a very dangerous disease, with a possible fatal outcome, a lot of attention is paid to its treatment. For the treatment of hypoxic hypoxia, complex treatment is used, which includes eliminating the causes of the disease, as well as adjusting the functioning of the body's blood supply system. If hypoxia is presented in a mild form, it can be corrected by taking walks in the fresh air, as well as increasing the ventilation of the premises.
In case the degree of hypoxic hypoxia is more serious, there are several complex treatment methods. Most often, artificial oxygenation of the lungs is used. With this method, various oxygen pillows, masks, as well as an artificial lung ventilation system are used. In addition to this patient, drugs that expand the respiratory structure are prescribed.