Many of us take our breath away when climbing to a height, and when we are in poorly ventilated rooms, we feel tired and slightly dizzy. This is due to the lack of oxygen for our organs. If in the cases listed above 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 severe consequences or even death. This article discusses the main characteristics of the concept of hypoxia, the principles and classifications 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 entire body, or local, affecting certain organs. Although hypoxia is a pathological disease, various levels of arterial oxygen concentration are acceptable in the case ofcertain physical conditions, such as hypoventilation training or active exercise.
Exogenous or hypoxic hypoxia is associated with climbing to high altitudes, and this causes even in he althy people altitude sickness, leading to fatal consequences: pulmonary edema and acute cerebral edema of the brain. Hypoxia also occurs in he althy individuals when breathing mixtures of gases with low oxygen concentrations, such as during scuba diving while using closed-loop rebreather systems that control the oxygen content of the air supplied. An artificially induced moderate state of hypoxia is used specifically during training at high altitudes to develop adaptations at both the systemic and cellular levels.
Hypoxia is a common complication in newborns resulting from preterm birth. Since the fetus's lungs develop by the end of the third trimester, premature babies are often born with underdeveloped lungs. Infants at risk of hypoxia are placed in incubators that provide small organisms with oxygen and positive airway pressure.
Degree of hypoxia
There are several degrees of pathology:
- Easy. Manifested during normal physical activity.
- Moderate. The degree manifests itself in chronic hypoxia in the normal state.
- Heavy. Manifested during an acute attack of hypoxia and can lead to coma.
- Critical. strong manifestationhypoxia, can be fatal.
Generalized hypoxia
In altitude sickness, when hypoxia develops less progressively, symptoms include:
- fatigue,
- numbness,
- tingling limbs,
- nausea and anoxia.
In severe hypoxia observed:
- confusion of consciousness,
- lack of orientation,
- hallucinations,
- behavioral change,
- nagging headaches,
- severe shortness of breath,
- manifest tachycardia,
- pulmonary hypertension leading to slow heart rate, low blood pressure and death.
Hypoxia is the result of impaired transport of O2 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 levels, changes in blood flow to the end tissue and problems with the respiratory rhythm.
Oxygen in the blood has a constant connection with hemoglobin, so any interference with this carrier molecule prevents the delivery of oxygen to the periphery. Hemoglobin increases the oxygen content in the blood by about 40 times. When the ability of hemoglobin to transport oxygen is disrupted, 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 condition. This hypoxiacauses a heart attack, which reduces the overall blood flow, which leads to further destruction in the tissues. Inadequate 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,
- blood shunting in the lungs,
- diseases that interfere with the full functioning of the lungs, resulting in a mismatch between 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 occurs at high or low altitudes. Hypoxic hypoxia can be divided into hypobaric and normobaric. The first refers to cases when a person enters the conditions of rarefied air and low pressure, as well as low oxygen content. This happens in the mountains or on low- altitude aircraft that are flown 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.
Reasons
Causes of hypoxic hypoxia canbe quite varied. Of the main ones, we can distinguish:
1) Discharged air at altitude. This is one of the most common causes of hypoxia, which is present even in he althy people.
2) Poor ventilation in closed rooms with a lot of people. One of the most common household causes of hypoxic hypoxia.
3) Being in rooms that have no connection with the outside world. This includes various types of mines, wells, as well as submarines.
4) Failure of the breathing apparatus in a highly gassed environment. For example, working in smoky rooms with a faulty gas mask.
Symptoms
The symptoms and consequences of hypoxia depend on the body's ability to respond to a lack of oxygen, as well as on the degree of hypoxia that occurs. 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 highlighting that the nervous and cardiovascular systems are most susceptible to hypoxia, which is characterized by a rapid or reduced heartbeat. In acute hypoxia, one of the cerebral hemispheres may malfunction, 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 exertion. Perhaps the appearance of chronic fatigue due to lack of oxygen for all organs.
Types of hypoxic conditions
There are two varieties:
Anemic hypoxia
Hemoglobin is responsible for transporting oxygen throughout the body. Hemoglobin deficiency leads to anemia, which causes anemic hypoxia. Inadequate iron content 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 is usually a chronic process that is compensated over time by an increased level of red blood cells through increased erythropoietin.
Acute hypoxia
Severe hypoxic exogenous hypoxia is characterized by an increase in heart rate and respiration, the occurrence of tachycardia, 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 the person can keep his body normal. If the attack is not eliminated immediately, 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 typical in the period of severe illness, proceeds for quite a long time. This is the main difference from acute hypoxia. With a long period, the body adapts to the conditions of lack of oxygen 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 during acute hypoxia, after the elimination of symptoms, all organs return to their normal state, then during chronic hypoxia, the body is rebuilt forever.
Histotoxic hypoxia
Histotoxic hypoxia occurs when the level of oxygen in cells is within the normal range, but the cells cannot use it effectively due to non-performing oxidative phosphorylation catalysts. This is what happens with cyanide poisoning.
Consequences of hypoxia
The consequences of hypoxic hypoxia are very diverse. If the cells of the body do not have enough oxygen, the electrons are converted into pyruvic acid during lactic acid fermentation. 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 the mitochondria, which can be caused by hypoxemia, poor circulation (eg, shock), or a combination of both. This condition, which has a long and severe form, leads to cell death. Pulmonary hypertension adversely affects survival in hypoxemia, to the extent that elevated mean pulmonary artery pressure rises. Chronic hypoxemia increases mortality with any severity of the disease.
Numerous studies in hypoxemic patients 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 electricity costs. They provide a constant source of oxygen and eliminate the costly transport of oxygen cylinders. In offices and residential areas, climate-controlled rooms are equipped, in which temperature and humidity are maintained at a constant level. Oxygen is always available in this system.
Treatment of hypoxia
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 the elimination of the causes of the disease, as well as the adjustment of the body's blood supply system. If hypoxia is present 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 treatments. The most commonly used artificial saturation of the lungs with oxygen. With this method, various oxygen pillows, masks, as well as an artificial ventilation system are used.lungs. In addition to this patient, drugs are prescribed that expand the respiratory structures.
