As you know, the difference in atmospheric pressure affects the well-being of a person. This is especially well known to people who are fond of mountaineering or go down deep into the water. A decrease in the atmospheric pressure of the environment for a short time is usually not accompanied by severe disturbances for the body. Nevertheless, a long stay in the "discharged" air is very dangerous. Some people develop a condition called decompression sickness during sudden changes in pressure. The severity of the condition is determined by the degree of impact on the person, the body's defenses, as well as the timely measures taken by the doctor. Although decompression decompression sickness is treatable in most cases, there are many cases of death. The connection of atmospheric pressure with this pathology was established in the middle of the 17th century by the scientist Boyle. Nevertheless, this medical phenomenon is still being studied.
What is decompression sickness?
This pathology is associated with occupational harmfulimpact on the body. Despite the fact that R. Boyle is one of the first scientists who established the relationship between a drop in atmospheric pressure and changes in the tissues of living organisms (the eyeball of snakes), decompression sickness became known to the world much later. This happened at the end of the 19th century, when the first air pumps and caissons were invented. At that time, pathology began to be attributed to occupational hazards. People working under compressed air to build tunnels underwater did not notice any change at first. Deterioration of the general condition appeared at the moment when the atmospheric pressure decreased to normal figures. For this reason, the pathology has a second name - decompression sickness. Depth is the main component of this state, since it is there that high pressure, unusual for our body, is noted. The same goes for height. Considering that the symptoms of a pathological condition appear with a pressure drop (from high to low value), diagnosis is not difficult for an experienced specialist.
Who gets decompression sickness?
Decompression sickness does not occur suddenly and for no reason. There is a risk group - that is, people prone to this pathology. The activities of these persons should be directly related to changes in atmospheric pressure. Previously, only caisson workers and climbers were affected by the disease. In the modern world, the risk group has increased markedly - astronauts, pilots and divers have also been included in it. Despite the fact thatthese professions are dangerous, decompression sickness is not the norm. It affects only those who neglect safety precautions or have risk factors. Among them, the following provocative effects are distinguished:
- Slowing down of blood circulation in the body. This happens with dehydration and hypothermia. Also, a slowdown in blood flow is observed with aging and cardiovascular pathologies.
- Formation in the blood of zones with reduced pressure. This phenomenon is accompanied by the appearance of small air bubbles. A risk factor that provokes this condition is excessive physical activity before diving into water or climbing to a height.
- Increased body weight. This is another factor that contributes to the accumulation of air bubbles in the blood.
- Reception of alcoholic beverages before diving or climbing to a height. Alcohol promotes coalescence of small air bubbles, thereby increasing their size.
Altitude decompression sickness: mechanism of development
As is known from the laws of physics, atmospheric pressure affects the solubility of gases in a liquid. This rule was formulated by the scientist Henry. According to him, the higher the ambient pressure, the better the gas dissolves in the liquid. Given this rule, we can conclude how decompression sickness develops in persons at high altitude. In connection with a long stay in the zone of high atmospheric pressure, the body of pilots and astronauts, as well as climbers, gets used tothis environment. Therefore, the descent to the atmosphere familiar to us causes a sharp deterioration in their condition. Due to the drop in pressure, blood gases begin to dissolve worse, gathering into air bubbles. What is the danger of decompression decompression sickness for pilots and why? Air bubbles formed in the bloodstream can increase in size and block the vessel, thereby causing tissue necrosis in this area. In addition, they tend to move around the body and enter the vital arteries and veins (cerebral, coronary, pulmonary). These air bubbles act as an embolus, or a blood clot, that can cause not only severe impairment of the condition, but also death.
Development of decompression sickness in divers
Decompression sickness of divers has the same mechanism of development. Due to the fact that at great depths atmospheric pressure is higher than at the surface, with a sharp decrease in blood gases, blood gases begin to dissolve poorly. However, if safety precautions are observed and there are no risk factors, this can be avoided. In order for a diver not to get decompression sickness, the following conditions are necessary:
- Using an oxygen tank that contains the necessary gas mixtures to reduce compression at depth.
- Gradual rise to the ground. There are special techniques that teach divers to swim out of the depths correctly. By gradually rising, the level of nitrogen in the blood is reduced, thereby preventing the formation of bubbles.
- The rise in the bathyscaphe is a specialsealed capsule. It helps to prevent a sudden pressure drop.
- Desaturation in special decompression chambers. Due to the removal of nitrogen from the body, lifting does not cause a deterioration in the solubility of blood gases.
Types of decompression sickness
There are 2 types of decompression sickness. They are distinguished by the fact in which vessels the air bubbles are located. In accordance with this, each of them is characterized by its own clinical picture. In type 1 bends, gas accumulates in the small capillaries, arteries, and veins that supply blood to the skin, muscles, and joints. In addition, air bubbles can accumulate in the lymphatics.
Underwater and high- altitude decompression sickness type 2 is a great danger. With it, gas emboli affect the vessels of the heart, lungs, brain and spinal cord. These organs are vital, so violations in them are of a serious nature.
Clinical picture
The clinical picture of the pathology depends on which vessel is affected by air bubbles. Signs such as itching, scratching, pain in muscles and joints, aggravated by turning the torso, walking, characterize type 1 decompression sickness. This is how uncomplicated decompression sickness manifests itself. Symptoms characteristic of type 2 are much more serious. With damage to the vessels of the brain, there may be the following clinical manifestations: loss of visual fields, decreased visual acuity, dizziness, doubling of objects in the eyes, noise inears. Embolism of the coronary arteries is manifested by angina pectoris and shortness of breath. With the defeat of the pulmonary vessels with small air bubbles, coughing, suffocation, lack of air are observed. All these symptoms are typical for moderate decompression sickness. In more severe cases, there are significant circulatory disorders with a possible fatal outcome.
Severity of decompression sickness
Distinguish between mild, moderate and severe decompression sickness. In the first case, the deterioration of the condition is insignificant and reversible within a short time. A mild degree is characterized by weakness, muscle and joint pain that occurs periodically, skin itching and rashes on the body. Usually these phenomena occur gradually and go away on their own. With moderate severity, significant violations occur. Pain in the joints and muscles is constant and more intense, shortness of breath, cough, discomfort in the heart area, and neurological symptoms join. This form requires urgent treatment. A severe form of decompression sickness can be manifested by significant respiratory depression, urination disorders, paresis and paralysis, myocardial infarction, etc. A stroke in the large vessels of the brain, as well as pulmonary embolism, can lead to death.
Diagnosis of decompression sickness
Diagnosis of decompression sickness is not difficult, since the pathology develops already in the first hours after rising from a depth or landing. The clinical picture makes it possible to correctly assesshuman condition in most cases. If a lesion of medium and large vessels is suspected, instrumental methods of examination are required. It is especially important to conduct coronary angiography, MRI of the brain, ultrasound of the veins and arteries of the extremities.
X-ray diagnostics for decompression sickness
With moderate to severe decompression sickness, bones and joints are often affected. In some cases, the spinal cord is also involved in the process. X-ray method of research allows to correctly diagnose decompression sickness. The following changes in the osteoarticular system are distinguished: areas of increased ossification or calcification, changes in the shape of the vertebrae (expansion of the bodies and decrease in height) - brevispondylia. In this case, the disks remain intact. If the spinal cord is also involved in the pathological process, then its calcifications can be detected, shaped like a shell or a cloud.
Decompression sickness treatment
It should be remembered that with timely assistance, decompression sickness can be cured in 80% of cases. For this, special pressure chambers are used, into which oxygen is supplied under high pressure. Thanks to them, the body undergoes recompression, and nitrogen particles are removed from the blood. The pressure in the pressure chamber is reduced gradually so that the patient adapts to new conditions. In case of emergency, it is necessary to carry out cardiopulmonary resuscitation, start the supply of “pure” oxygen using a mask.
Preventiondecompression sickness
To prevent the development of decompression sickness, it is necessary to adhere to safety procedures at depth and high in the air. During the ascent from the water, make stops so that the body can adapt to atmospheric pressure. It is also important to use special equipment - a diving suit and oxygen tanks.
