Why you can't breathe pure oxygen for a long time. Oxygen therapy. Artificial respiratory environment. Depression sickness. Nitrogen poisoning

The atmosphere for a spaceship. Undoubtedly, the air we breathe is the best environment for our body. But now a person leaves the earthly atmosphere and goes on a space flight. There is no air outside the ship. If you take it with you, the oxygen content in it will quickly drop, and carbon dioxide will accumulate. It is necessary to constantly regenerate (restore) the composition of the atmosphere in the manned cabin of the ship. For short flights, it is sufficient to grab cylinders of compressed or liquid oxygen and gradually add it to the cabin air. Carbon dioxide can be absorbed by soda lime, sorbents (zeolite), or removed by freezing, condensation.

And what should be the composition of the atmosphere of an inhabited space cabin? It would seem the easiest thing - the same as the composition of the natural atmosphere. But it turns out that the question is not as simple as it might seem. Indeed, for breathing, it seems that only one gas is enough - oxygen. Four-fifths of the volume nitrogen atmospheric air, just a diluent gas. Experiments have confirmed that both animals and humans can perfectly live in an atmosphere where nitrogen is replaced by another gas - helium (we will talk about this later), therefore, you can do without nitrogen. Can't you breathe pure oxygen? But in spite of famous saying"You can't spoil porridge with butter", oxygen at its high concentrations, or rather at its high pressure, is even harmful.

If a person breathes pure oxygen for many hours in a row, they develop respiratory irritation and pneumonia. Experimental animals - from frogs to monkeys - become ill and often die after a few days in an oxygen atmosphere. To avoid high oxygen partial pressures, the total pressure can be reduced accordingly. Then oxygen poisoning will not occur. And the use of such a monogas (that is, one-gas) environment greatly simplifies the whole problem of creating an artificial atmosphere. Space flight programs developed in the United States provide for the filling of manned cabins with oxygen only, but at a reduced (approximately three times) pressure compared to the earth's pressure. Such an environment, in the event of a breach of the cabin sealing, postpones the development of hypoxia, since the partial pressure of oxygen here is one and a half times higher than usual. There is also less risk of developing so-called decompression disorders. (At an altitude of more than 18 kilometers, the air pressure is so low that gases dissolved in the blood, mainly nitrogen, begin to vigorously release in the form of bubbles - the blood literally boils. However, more about decompression disorders a little later.) In addition, the mass of such an artificial atmosphere three times less than the same volume of air, which means that the entire spacecraft becomes lighter. At the same time, oxygen, devoid of a diluent gas (nitrogen serves as nitrogen in ordinary air), creates a great fire hazard. Let us recall from school experiments how a heated simple iron wire burns up in pure oxygen with a bright flame. A tragic incident is also memorable: two American astronauts died from burns during ground tests of the space capsule.

Land in miniature. All that has been said applies to today's relatively short flights. In the future, the requirements for methods of creating an artificial atmosphere for spaceships may change. It's about long journeys to others celestial bodies... Such flights will last, perhaps, not months, but years. Then the use of ready-made sources (reserves) of oxygen will become unprofitable. Let's remind: every day a person "eats" about a kilogram of oxygen - 900 liters of gas at normal atmospheric pressure. To solve this problem, the so-called closed ecological systems... Such a system is like our Earth in miniature. In it, green plants serve to supply a person with oxygen and absorb the carbon dioxide released by him.

In this regard, the unicellular alga, chlorella, has become very famous. 20-30 liters of its culture, which resembles the water of a "blooming" pond, is enough to provide a person with oxygen for up to two months. Higher plants are even more productive: say, spreading tree it is capable of "feeding" several dozen space travelers with oxygen, but it would take too much space by itself.

Closed ecological systems have been repeatedly tested by Soviet scientists and engineers in experiments. The testers lived in a hermetically sealed room for months. Plants in a specially designed greenhouse used carbon dioxide and other human waste products in the process of photosynthesis, providing it, in turn, with oxygen and fresh vitamin food.

True, it is not so easy for a person and his green companions to get along. Each partner has its own requirements for the composition of the environment, temperature, humidity. There are still many problems to be solved before astronauts embark on long-term flights to other planets. And then on these planets (where, as we now know, there will not be an atmosphere suitable for human breathing), inhabited colonies will appear, the terrestrial atmosphere in miniature will begin to be created there as well.

Will these be cities protected by giant transparent caps? Or huge underground, or rather submarsal, sublunary halls? While they exist only in the imagination of science fiction writers. But over time, they will be embodied in real projects. In any case, their inhabitants will have to be provided with oxygen, food, water. And for this - to create gardens, vegetable gardens, livestock farms. In such cities, participants in space expeditions will be able to live and work as long as they like.

Than an aquanaut to breathe. And now we will descend from the sky-high heights into the depths of the ocean. Nowadays, mankind, step by step, is mastering the depths of the sea - "hydrocosm", primarily the coastal zone - the ocean shelf. Oil, food resources ... Thousands of books have been written about the riches of the sea. But even here, in the depths, the explorer encounters many obstacles. And including the problem "what to breathe?"

Of course, this problem does not arise if a person dives into water without any equipment, as pearl divers or some modern researchers and athletes, for example, Jacques Mayol, who reached 100 meters depth without any breathing equipment: such divers under water, of course, do not breathe at all. (We will talk about holding your breath further). The matter is quite simple if a person is submerged in a hermetically sealed apparatus with a hard shell, which reliably protects him from the pressure of the water column. It could be Picard's bathyscaphe, in which the brave scientist reached the deepest point of the world ocean (11 kilometers!) - the bottom of the Mariana Trench. It may also be an "ordinary" submarine, the prototype of which was Jules Verne's Nautilus. In such devices, as in the cockpits of a spacecraft, a person can breathe air of an ordinary composition. All that is needed is to replenish oxygen and remove excess carbon dioxide.

Another thing is a diver in his "soft" suit. Underwater, it is exposed to tremendous pressure. It increases for every 10 meters of depth by the whole atmosphere (1 kilogram per square centimeter of surface). In order for the diver to breathe normally, air is supplied to the suit under the same pressure. And this means that already at a depth of 10 meters, a diver finds himself in a gaseous medium under a pressure of twice the atmospheric pressure, and at a depth of 90 meters - 10 times!

In the "underwater house". Now more and more researchers deep sea equip "underwater houses". The pressure of the gaseous medium filling such a "house" is also maintained at a level equal to the pressure of water at the same depth. Here aquanauts can live without rising to the surface for many days and weeks. As needed, they can go out into the surrounding water element for scientific observations. They go out, dressed in simple wetsuits, through the open hatch. Water does not penetrate into the "house" - this is prevented by the pressure of the gas environment in the room. After completing the work, the aquanauts return to the "home" to rest. This method of depth development has serious advantages over conventional short-term diving descents.

But to make this clear, a few words must be said about d decompression disorders, mentioned in passing in connection with space problems.

Insidious "box". After a diver has spent some time at depth, he has to be lifted up very carefully. The fact is that at a depth under increased pressure in the fluids of his body, an excess amount of gas dissolves in the tissues. If the pressure in the environment quickly drops to normal, this excess gas is released intensively in the form of bubbles, which are very dangerous: they can clog blood vessels, including in vital organs - in the brain, heart, lungs. Then the so-called decompression disorders occur, or decompression sickness. In mild cases, decompression disorders are limited to pain, in severe cases, the victim is threatened with paralysis, including paralysis of breathing and cardiac activity. To avoid the "caisson", it is necessary to observe specially designed decompression modes, that is, pressure reduction. From great depths, the diver is raised for many days. This dramatically reduces the productivity of his labor. In fact, it happens like this: only a few hours of work under water, a whole week - for the descent (it also cannot be carried out hastily - this will be discussed further below) and the ascent.

But if an aquanaut does work while living in an "underwater house", he has to be lowered and decompressed only at the beginning and at the end - at the end of a multi-day or even multi-week shift. The benefits to the efficiency of his work are obvious, and his health is in less danger.

And oxygen can become poison. By itself, the increase in gas pressure with increasing depth of immersion does not interfere with breathing. After all, this pressure (in contrast to the excess pressure used in high-altitude aviation) acts not only from the inside of the lungs, but also on the entire surface of the human body. At the same time, this factor is not indifferent to both respiration and other functions of the body. First, with an increase in air pressure, the partial pressure of the oxygen contained in it also increases. And then this gas can turn into dangerous enemy... We have already talked about the "pulmonary" form of oxygen poisoning. If a person breathes oxygen for a long time under pressure, seizures similar to epilepsy may begin: the function of the nerve centers is disrupted. (You may ask: how do they treat oxygen, and even under pressure? 300 mm Hg).

To comply with this condition, as the depth of diving (and hence the pressure of the gas environment) increases, the percentage of oxygen in the breathing mixture is reduced. So, at a depth of 40 meters, they give a mixture containing 5% oxygen (instead of the usual 20.9%), at a depth of 100 meters - only 2% O2, etc.

Intoxicating ... nitrogen. Another problem is nitrogen. We are used to thinking that nitrogen is a physiologically neutral gas. Indeed, free nitrogen does not take part in the vital processes of the organism of animals and humans. The assimilation of nitrogen from the atmospheric air and the production of proteins on this basis is the business of autotrophs-plants and some microorganisms. In our body, the inhaled nitrogen only passively dissolves in the blood and other body fluids.

It's a different matter with deep diving. ... A suit is put on, the serviceability of the equipment is checked, and the diver disappears under the water. Deeper, deeper. But what is it? His movements become impetuous, uncoordinated, reports - hasty, confused. He's clearly agitated. Typical drunkenness. This phenomenon, which manifests itself when breathing compressed air starting from a depth of 60-70 meters, was actually called "deep intoxication" at first. And nitrogen was the culprit. At a high partial pressure of this gas, it exhibits a typical narcotic effect, similar to the action of "laughing gas" - nitrous oxide, which has long been used for pain relief in surgical and obstetric practice.

Nitrogen narcosis is dangerous. There were cases when a person at a depth tore off his underwater equipment and died. This is somewhat reminiscent of the phase of increased well-being (euphoria) with a lack of oxygen: let us again recall the described tragedy on the Zenith balloon. Therefore, when diving to great depths in breathing mixtures nitrogen is replaced with helium- a gas that does not have such an insidious property. There are other reasons for such a replacement.

Why is it difficult to breathe under pressure. The fact is that the deeper the immersion, the higher the pressure. gas mixture, the greater is its density. Accordingly, the resistance to air flow in the trachea and bronchi also increases. This resistance, as we will learn below, is called resistive. Respiratory muscles have to work with great strain in order to provide ventilation in such conditions. "You hardly suck in the air and then blow it out with force" - this is how S. Miles characterized in his book "Underwater Medicine" the sensations of a diver when breathing at a depth.

It becomes especially painful when a person has to perform strenuous work under water, requiring a significant increase in breathing. However, he suffers from severe shortness of breath. "A horror that I have not experienced" - this is how one of the submariners expressed this feeling.

Pros and cons of helium. Helium has a molecular weight about 7 times less than nitrogen, and, accordingly, a lower density. At a depth of 50 meters, the breathing mixture of 96.5% He2 and 3.5% O2 (which corresponds to normal oxygen partial pressure) has the same density as normal air at sea level. And at a depth of 200-300 meters, where it is almost impossible to breathe with a nitrogen-oxygen mixture, the helium mixture allows a person not only to breathe at rest, but also to perform rather heavy muscle work without shortness of breath.

Unfortunately, helium also has its drawbacks. When a person inhales this gas, his voice changes. It becomes high, as if the speed of a magnetic tape was confused with a voice recording. Like Pinocchio's voice in a famous radio show. We have to use special radio equipment to make out the words spoken by the diver. Another defect of helium: it is too thermally conductive. In an environment containing this gas, you have to maintain a higher temperature, otherwise the person will freeze. But it is also dangerous to overheat in a helium environment. In a helium atmosphere, the thermal comfort zone is narrowed. In addition, although helium, unlike nitrogen, does not cause a narcotic effect, at great depths - over 250-300 meters, especially with a rapid increase in pressure - it still has an adverse effect on the central nervous system. The aquanaut's hands begin to tremble ("helium tremor"), drowsiness appears, and performance is impaired.

How to deal with this so-called "high pressure nervous syndrome"? The fact is that this syndrome in a number of features is the exact opposite of "nitrogen anesthesia". Therefore, scientists proposed to "knock out a wedge by a wedge" by adding small concentrations of nitrogen to helium mixtures for deep-sea diving. This is what they are doing now, and not without success.

Barriers to the depths of the ocean. Currently, aquanauts are successfully working at depths of up to 300 meters. However, it is natural to try to increase the maximum immersion depth at which a person could live and work. For this purpose, experiments are being carried out in special chambers, where pressure is created corresponding to a certain immersion depth. So far, world achievements are in the range of 600-700 meters of water column. But further immersion encounters some kind of barriers: the density of even the helium medium becomes ten times more than normal, and breathing resistance becomes formidable. True, in some cases, equipment is used that creates pressure fluctuations in the respiratory tract of a person, helping him to inhale and exhale - like auxiliary ventilation of the lungs, which we will discuss later. Such equipment has already been tested during the recovery of sunken ships. As already mentioned, other "defects" of helium turn out to be a significant obstacle on the way into the depths: a nervous syndrome of high pressure (at certain depths it is almost impossible to fight it) and a "temperature barrier" - at a depth of about a kilometer, as was calculated, a person will suffer from hypothermia and overheating at the same time.

Can a person breathe water? Here it should be said about one "crazy idea": to make a person breathe ... water! After all, then all barriers will disappear, and the aquanaut will feel "at home" even at the bottom of the Mariana Trench. The problem of decompression will also disappear: ascent from any depth will take only a few minutes. No, it comes not at all about creating Ichthyander ("fish man") by sewing the gills of a shark into a man, as Dr. Salvator did in A. Belyaev's novel "The Amphibian Man".

Scientists believe that our lungs can take over the functions of the gills. "The first inhabitants of our planet, - wrote the Dutch researcher D. Kilstra, - having adapted to aquatic environment, breathed with gills, the purpose of which is to extract the maximum amount of oxygen from the water. In the course of evolution, animals mastered the oxygen-rich atmosphere of the land and began to breathe with their lungs ... Both in the lungs and in the gills, oxygen through thin membranes penetrates from the environment into the blood vessels, and carbon dioxide is released from the blood into environment... So, the same processes take place in the gills and in the lungs. This raises the question: could an animal with lungs breathe in an aquatic environment if it contained a sufficient amount of oxygen? "

In the experiments conducted by D. Kilstra, mice placed in a physiological solution saturated with oxygen lived up to 18 hours, making slow respiratory movements. They died mainly for two reasons. First, for pumping water through the lungs, the efforts of the respiratory muscles are 36 times greater than for their ventilation with air. Secondly, although oxygen was delivered to tissues in the right amount, carbon dioxide was poorly removed by such a solution. To eliminate this disadvantage, the so-called organophosphorus compounds began to be used for "liquid breathing". They carry oxygen and especially carbon dioxide so well that they are used as the basis for artificial blood substitutes.

As for the difficulties in ventilation of the lungs, the way out can be found in pumping the solution through the respiratory tract using equipment similar to that used for artificial circulation. Experiments have confirmed the reality of this method: laboratory dogs perfectly "breathed" the pumped solution. Whether it will be possible to create an "amphibian man" for a while, or liquid breathing will turn out to be a dead-end problem (there are still considerable difficulties on the way of its solution), the future will show.

In the bowels of the Earth. The considered problems relate not only to the exploration of space and hydrospace. There is also a third "space" - geocosmos - the interior of our planet, a source of heat and minerals. And it has been the least researched. So far we know the structure of only a thin film of the shell, of the order of a thousandth of the radius the globe... We have already mentioned the superdeep well on the Kola Peninsula. At a depth of 7 kilometers, the temperature, as it turned out, is 150 °, and the rock pressure is truly colossal.

Let us recall "Journey to the Center of the Earth" by J. Verne. Will the geospace ship soon move to the belly of our planet? But even earlier, scientists will have to solve, among other problems, how the pioneers of the earth's interior will breathe.

When is hypoxia helpful? We have already said that the atmosphere of a normal composition is optimal for a person. True, the reserve capacity of the body is great. Many generations of aborigines live in the Andes and the Himalayas at an altitude of more than 4-5 kilometers with a partial oxygen pressure that is half that at sea level. Some experts believe that, under certain conditions, short-term exposure to mild hypoxia or hypercapnia may be beneficial by stimulating relevant regulatory mechanisms. To this end, they propose to create an "active atmosphere" in the cockpit during space flights, at times either decreasing the oxygen content in it, or increasing the concentration of carbon dioxide. This should, in their opinion, counteract harmful influence weightlessness and insufficient muscular activity of astronauts.

Should you drink an oxygen cocktail? Changing the composition of the inhaled air has a positive effect on certain diseases. And above all - with insufficient oxygen supply to the tissues. Breathing with mixtures enriched with this gas, directly from oxygen cushions, in "oxygen tents" is widespread. However, you need to know that the gain in oxygen supply to the body in such cases is small: most of(over 90%) oxygen is carried by the blood in conjunction with hemoglobin, and this pigment in arterial blood and breathing with ordinary air is "oxygenated" (saturated with oxygen) by 96-97%. A slight increase in the amount of oxygen dissolved in blood plasma does not play a significant role. And absolutely useless, from our point of view, attempts to give people (especially healthy people) additional oxygen nutrition in the form of all kinds of "oxygen cocktails", "cereals", etc. Indeed, if tissues are spent for some 5 minutes a whole liter of oxygen, then how much will add a few milliliters of this gas, whipped into "cocktails", which will slowly seep through the wall of the digestive tract for tens of minutes? Perhaps, such a "treatment" has, rather, a psychological meaning ... At least there is no harm, at least.

Saves oxygen under pressure. It is quite another matter when the body needs help to get out of a hypoxic state - for example, in case of poisoning with carbon monoxide, which blocks blood hemoglobin. Then the patient is placed in a pressure chamber, where he breathes oxygen under pressure (up to 2-3 atmospheres). Under these conditions, the plasma of his blood dissolves the amount of this gas, already sufficient for therapeutic effect... Many thousands of people have already been saved by the method of so-called hyperbaric oxygenation.

Oxygen under high pressure is now used in those situations when it is necessary to supply it directly to tissues, bypassing the blood. This is done during operations on a "dry heart", when the surgeon is forced to temporarily stop the work of this organ in order to correct its congenital or acquired defect.

Hyperbaric oxygenation is also used in obstetric practice if the body of the mother or newborn suffers from a lack of oxygen.

Of course, in all these cases, doctors take measures to ensure that oxygen manifests itself only as a friend, but not an enemy, that is, so that the patient does not have time to develop oxygen poisoning. The health of the personnel involved in the operation in the pressure chamber is also protected: they breathe, though under pressure, with air of ordinary composition, while the patient receives pure oxygen. Particularly famous is the large baroque complex created at the All-Union Scientific Center of Surgery under the leadership of Academician B.V. Petrovsky.

More about healing air. There are a number of other therapeutic uses for the "artificial atmosphere". So, in children with impaired airway patency, inhalation of a mixture of oxygen with helium has a good effect. The latter, as mentioned, reduces breathing resistance. A pulmotron is being created in one of the Leningrad clinics. It will be a comfortable ward where patients will be able to live and receive treatment for a long time. Special devices will make it possible to maintain here such a composition of the atmosphere, which is indicated for certain diseases. It is possible that in the future, such "thrones" will be used for the prevention of pulmonary diseases. Then millions of people will strengthen their health in them. of different ages and professions. (... written during the "stagnation")

Everyone knows from childhood that a person cannot live without oxygen. People breathe it, it takes part in many metabolic processes, saturates organs and tissues with useful substances. Therefore, oxygen treatment has long been used in many medical procedures, thanks to which it is possible to saturate the body or cells with important elements, as well as improve health.

Lack of oxygen in the body

The person breathes oxygen. But those who live in large cities with developed industry experience a lack of it. This is due to the fact that in megacities, the air contains harmful chemical elements... In order for the human body to be healthy and fully functioning, it needs pure oxygen, the proportion of which in the air should be approximately 21%. But various studies have shown that in the city it is only 12%. As you can see, the inhabitants of megalopolises receive a vital element 2 times less than the norm.

Oxygen deficiency symptoms

• increased breathing rate,
• increased heart rate,
• headache,
• the work of organs slows down,
• violation of concentration,
• the reaction slows down,
• lethargy
• drowsiness,
• acidosis develops,
• cyanosis of the skin,
• change in the shape of the nails.

Consequences of lack of oxygen

As a result, the lack of oxygen in the body negatively affects the work of the heart, liver, brain, etc. The likelihood of premature aging, the appearance of diseases and respiratory organs increases.

Therefore, it is recommended to change your place of residence, move to a more environmentally friendly area of ​​the city, and it is better to move out of town altogether, closer to nature. If such an opportunity is not foreseen in the near future, then try to get out to parks or squares more often.

Since residents of large cities can find a whole "bunch" of diseases due to the lack of this element, we suggest that you familiarize yourself with the methods of oxygen treatment.

Oxygen treatment methods

Oxygen inhalation

It is prescribed for patients suffering from diseases of the respiratory system (bronchitis, pneumonia, pulmonary edema, tuberculosis,), for diseases, for poisoning, malfunctions of the liver and kidneys, and for shock conditions.

Oxygen therapy can also be done for the prevention of residents of large cities. After the procedure appearance a person becomes better, mood and general well-being rises, energy appears, strength for work and creativity.

Oxygen inhalation procedure

Oxygen inhalation requires a tube or mask through which the breathing mixture will flow. It is best to carry out the procedure through the nose, using a special catheter. The proportion of oxygen in breathing mixtures is from 30% to 95%. The duration of inhalation depends on the state of the body, usually 10-20 minutes. This procedure is often resorted to in the postoperative period.

Anyone can purchase the necessary oxygen therapy devices in pharmacies and carry out inhalation on their own. Oxygen cartridges are usually commercially available, approximately 30 cm in height, with an internal content of oxygen gas with nitrogen. The cylinder has a nebulizer for breathing gas through the nose or mouth. Of course, the balloon is not endless in use, as a rule, it lasts for 3-5 days. It is worth using it daily 2-3 times.

Oxygen is very beneficial for humans, but an overdose can be harmful to them. Therefore, when carrying out independent procedures be careful and don't overdo it. Do everything according to the instructions. If, after oxygen therapy, you have the following symptoms - dry cough, convulsions, burning sensation behind the breastbone - then immediately consult a doctor. To prevent this from happening, use a pulse oximeter, it will help monitor the oxygen content in the blood.

This procedure means the effect of high or low pressure on the human body. As a rule, they resort to an increased one, which is created in pressure chambers with different sizes for various medical purposes. There are large ones, they are designed for operations and childbirth.

Due to the fact that tissues and organs are saturated with oxygen, swelling, inflammation decreases, and cell renewal and rejuvenation is accelerated.

It is effective to use oxygen under high pressure for diseases of the stomach, endocrine and nervous systems, in the presence of problems with gynecology, etc.

It is used in cosmetology with the aim of introducing active substances into the deep layers of the skin, which will enrich it. This oxygen therapy improves the condition of the skin, it rejuvenates, and cellulite also disappears. On this moment oxygen mesotherapy is a popular service in cosmetology salons.

Oxygen baths

Are very helpful. Water is poured into the bath, the temperature of which should be approximately 35 ° C. It is saturated with active oxygen, due to which it has a therapeutic effect on the body.

After taking an oxygen bath, a person begins to feel better, migraines also pass, blood pressure normalizes, and metabolism improves. This effect occurs due to the penetration of oxygen into the deep layers of the skin and stimulation of nerve receptors. Such services are usually provided in spa salons or sanatoriums.

Oxygen cocktails

They are very popular now. Oxygen cocktails are not only healthy, but also delicious.

What are they like? The basis that gives color and taste is syrup, juice, phytonastes, in addition, such drinks are filled with foam and bubbles containing 95% of medical oxygen. Oxygen cocktails should be drunk for people suffering from diseases of the gastrointestinal, having problems with nervous system... Such a medicinal drink also normalizes blood pressure, metabolism, relieves fatigue, eliminates migraines and removes excess fluid from the body. If you consume oxygen cocktails daily, then a person has