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 under water. A reduction in atmospheric pressure for a short time is usually not accompanied by severe disturbances to the body. Nevertheless, a long stay in the "discharged" air is very dangerous. Some people with sudden changes in pressure develop a condition such as decompression sickness. The severity of the condition is determined by the degree of exposure to the person, the body's defenses, as well as timely measures taken by the doctor. Despite the fact that 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 professional harmful effects on the body. Despite the fact that R. Boyle is one of the first scientists to establish a relationship between a drop in atmospheric pressure and changes in the tissues of living organisms (snake's eyeball), 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 harm. People who worked in compressed air in order to build tunnels under water, at first did not notice any changes. General condition deterioration appeared at the moment when atmospheric pressure was reduced to normal numbers. For this reason, pathology has a second name - decompression sickness. Depth is the main component of this condition, since it is there that high pressure unusual for our body is noted. The same goes for height. Given that the symptoms of a pathological condition appear with a pressure drop (from high to low), diagnosis is not difficult for an experienced specialist.
Who is affected by decompression sickness?
Caisson disease does not occur suddenly and for no reason. There is a risk group - that is, people susceptible to this pathology. The activities of these individuals should be directly related to changes in atmospheric pressure. Previously, only caisson workers and climbers were affected. In the modern world, the risk group has increased significantly - they also include astronauts, pilots and divers. Despite the fact that these professions are dangerous, illness with decompression sickness is not the norm. It affects only those who neglect safety measures or have risk factors. Among them, the following provocative effects are distinguished:
- Slowing blood circulation throughout the body. This occurs with dehydration and hypothermia. Also, a slowdown in blood flow is observed with aging and cardiovascular pathologies.
- The formation of low blood pressure zones. This phenomenon is accompanied by the appearance of small air bubbles. The risk factor provoking this condition is excessive physical activity before immersion in water or ascent to a height.
- Increased body weight. This is another factor contributing to the accumulation of air bubbles in the blood.
- Drinking alcohol before diving or climbing to a height. Alcohol helps to merge small air bubbles, thereby increasing their size.
Altitude decompression sickness: a developmental mechanism
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 people at high altitude. Due to the long stay in the zone of high atmospheric pressure, the body of pilots and astronauts, as well as climbers, gets used to this environment. Therefore, the descent to our usual atmosphere causes them to sharply worsen. Due to the drop in pressure, blood gases begin to dissolve worse, collecting in 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 through the body and enter the vital arteries and veins (cerebral, coronary, pulmonary). These air bubbles act as an embolus, or thrombus, which can cause not only severe disturbances in the condition, but also a fatal outcome.
The development of decompression sickness in divers
Caisson disease of divers has the same developmental mechanism. Due to the fact that at great depths, atmospheric pressure is higher than on the surface, with a sharp decrease in it, blood gases begin to dissolve poorly. However, with safety precautions and no risk factors, this can be avoided. So that the diver does not get sick with caisson disease, the following conditions are necessary:
- Using an oxygen cylinder that contains the necessary gas mixtures to reduce compression in depth.
- Gradual rise to the ground. There are special techniques that teach divers how to swim out of the depths. Due to the gradual rise, the level of nitrogen in the blood is reduced, thereby bubbles do not form.
- The rise in the bathyscaphe is a special sealed capsule. It allows you to prevent a sharp 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 exact vessels in which air bubbles are located. In accordance with this, each of them is characterized by its clinical picture. With type 1 caisson disease, 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 lymphatic vessels.
Underwater and high-altitude decompression illness of 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, therefore, violations in them are serious.
Clinical picture
The clinical picture of the pathology depends on which particular vessel is affected by air bubbles. Signs such as skin itching, scratching, pain in muscles and joints, aggravated by turning the body, walking, characterize 1 type of caisson disease. This is how uncomplicated decompression sickness manifests. Symptoms characteristic of type 2 are much more serious. With damage to the vessels of the brain, the following clinical manifestations can occur: loss of visual fields, a decrease in its severity, dizziness, doubling of objects in the eyes, and tinnitus. Coronary embolism is manifested by angina pectoris and shortness of breath. With damage to the pulmonary vessels by small air bubbles, cough, suffocation, lack of air is observed. All these symptoms are characteristic of moderate decompression sickness. In more severe cases, significant circulatory disorders with a possible fatal outcome are observed.
Severity of decompression sickness
There are mild, moderate and severe decompression sickness. In the first case, the deterioration is insignificant and reversible for a short time. A mild degree is characterized by weakness, muscle and joint pain that occurs periodically, skin itching and rashes on the body. Typically, these phenomena occur gradually and pass on their own. With moderate severity, significant disturbances occur. The pain in the joints and muscles is constant and more intense, shortness of breath, cough, discomfort in the heart, neurological symptoms join. This form requires urgent treatment. A serious form of decompression sickness can be manifested by significant respiratory depression, urination disorders, paresis and paralysis, myocardial infarction, etc. stroke can lead to death in large vessels of the brain, as well as pulmonary embolism.
Diagnosis of caisson disease
Diagnosis of decompression sickness is not difficult, since pathology develops already in the first hours after rising from a depth or landing. The clinical picture allows you to correctly assess the condition of a person in most cases. If you suspect damage to medium and large vessels, instrumental examination methods are required. It is especially important to carry out coronarography, MRI of the brain, ultrasound of the veins and arteries of the limbs.
X-ray diagnostics for caisson disease
With moderate and severe caisson disease, bones and joints are quite often affected. In some cases, the spinal cord is also involved in the process. The X-ray method of research allows you 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) - brevispondilia. In this case, the discs remain intact. If the spinal cord is also involved in the pathological process, then you can find its calcifications, in the form resembling a shell or a cloud.
Decompression illness 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 particles of nitrogen are removed from the blood. The pressure in the pressure chamber is gradually reduced so that the patient adapts to new conditions. In case of emergency, it is necessary to carry out cardiopulmonary resuscitation, to begin supplying “pure” oxygen using a mask.
Prevention of decompression sickness
To prevent the development of decompression sickness, you must adhere to safety procedures at a depth and high in the air. During ascents 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.