Decompression sickness
The content of the article:
- Causes and risk factors
- Symptoms of decompression sickness
- Diagnostics
- Treatment
- Potential consequences and complications
- Forecast
- Prevention
Decompression sickness (decompression sickness, DCS, caisson, diving disease) is a disease caused by a person's rapid transition from an environment with high pressure to an environment with normal pressure. This is accompanied by the release of nitrogen bubbles from physiological fluids, dissolved in it at high pressure. Most often, the disease is observed in divers when they violate the rules for deep-sea work (too fast ascent or prolonged stay at depth).
Source: likar.info
The first cases of decompression sickness began to be recorded after 1841, when the caisson was invented - a special chamber for construction work under water (fixing bridge supports, building underwater tunnels). The workers went through the airlock to this chamber, where they carried out the necessary work. To prevent flooding of the caisson, compressed air was fed into it. After the work shift ended, the pressure was reduced to atmospheric. At the same time, many workers experienced severe joint pain, and some developed paralysis and even death.
Causes and risk factors
A certain amount of gas is dissolved in the blood and biological fluids of the human body, which depends on the pressure of the gas mixture above the surface of the liquids. If the gas pressure above the liquid becomes greater than that in the liquid, this leads to accelerated diffusion of the gas into the liquid. Otherwise, that is, when the gas pressure above the liquid becomes lower, the liquid "boils" - the previously dissolved gas is released from it. It is this kind of "boiling" of blood that is observed in divers during a rapid ascent to the surface, and it becomes the cause of decompression sickness.
When working at depth, the breathing mixture is supplied to divers under an increased pressure corresponding to the ambient pressure. For example, if a diver is working at a depth of 30 meters, the pressure of the breathing mixture should be 4 atmospheres. As a result, 4 times more nitrogen is dissolved in his blood than in people on the surface. Upon ascent, the hydrostatic pressure of the water decreases, and therefore the pressure of the respiratory mixture also decreases, which leads to the formation of nitrogen bubbles in the blood. With a slow ascent, nitrogen microbubbles with the blood flow enter the lungs, from where they are removed through the alveolar walls with exhaled air. If you ascend too quickly, the nitrogen bubbles do not have time to be excreted by the lungs. Platelets begin to attach to them, and then other blood cells, which leads to the formation of blood clots,which clog the vessels of the microvasculature. After a while, thrombi adhering to the walls of blood vessels break away from them, leading to a violation of the integrity of the vessels, hemorrhages into the surrounding tissues.
Factors that increase the risk of developing decompression sickness are:
- violation of the processes of regulation of blood circulation under water;
- age (the older the age, the higher the risk of developing decompression sickness);
- hypothermia;
- dehydration;
- significant physical activity before or during a dive;
- overweight;
- hypercapnia - may be due to the presence of impurities in the respiratory gas mixture, its economy;
- drinking alcohol before diving or immediately after surfacing.
Symptoms of decompression sickness
The clinical picture of decompression sickness, depending on the degree of damage to the nervous system, is manifested by the following syndromes:
- decompression damage to peripheral nerves - observed with mild decompression sickness, clinically manifested by neuralgia (pain along the affected nerve);
- decompression damage to the spinal cord - the latent period is short, the first symptoms of decompression sickness are girdle pain in the chest area and impaired skin sensitivity of the extremities. In the future, the victims develop dysfunctions of the pelvic organs, spastic paralysis of the legs, and damage to the hands is much less common. If specialized care is not provided on time, paralysis becomes irreversible;
- decompression brain damage - the duration of the latent period does not exceed a few minutes. The victims have anxiety, severe headache, weakness, constant nausea and repeated vomiting, impaired consciousness from mild lethargy to deep coma;
- multiple decompression lesions of the nervous system - observed in about 50% of cases. The combination of neurological symptoms of decompression sickness is determined by the severity and localization of damage to the central and peripheral nervous system.
Diagnostics
Diagnosis of decompression sickness is carried out on the basis of anamnesis data and a characteristic clinical picture of the disease. When conducting an X-ray examination, air bubbles are clearly visible in the synovial sheaths of the tendons, articular cavities and blood vessels.
Treatment
The effectiveness of the treatment of decompression sickness largely depends on the timeliness and correctness of the provision of first aid to the victim.
If only mild symptoms of decompression sickness (skin itching, severe fatigue, weakness) are observed and consciousness is preserved, the patient should be laid on his back with outstretched limbs. Provided that the consciousness is preserved and the pathology is mild, every 15-20 minutes you should drink a glass of warm non-carbonated water. To the injured, who are in a semi-conscious state or often lose consciousness, liquid should not be given!
In case of lung damage and severe shortness of breath, the victim must be seated. Patients in an unconscious state should be placed on their left side, bending the right leg at the knee joint for stability. This position prevents the entry of vomit into the respiratory tract.
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If the victim is in a state of clinical death, he is placed on his back and resuscitation measures are immediately started (artificial ventilation of the lungs, chest compressions).
At the prehospital stage, patients with decompression sickness are given oxygen therapy. Hospitalization is indicated in a hospital equipped with a pressure chamber. Transportation by air is undesirable - this is due to the fact that at high altitudes the air bubbles in the body begin to increase in size, leading to further deterioration of the condition.
The main treatment for decompression sickness is recompression. The patient is placed in a pressure chamber, where an increased pressure is created, and then it is very slowly reduced. The choice of the decompression mode is carried out by the doctor taking into account a number of factors (the form of decompression sickness, the time elapsed since the first signs appeared, the condition of the victim). In most cases, pressure is initially created in the pressure chamber, similar to a dive to 18 meters. Then it is lowered to normal gradually, over several hours, and in severe cases, days.
While in the pressure chamber, the patient breathes pure oxygen through a mouth-nose mask. It is periodically removed for 5-10 minutes in order to prevent oxygen poisoning.
Potential consequences and complications
Caisson disease can lead to the development of pneumonia, cardiac dystrophy, myocarditis, endocarditis, cardiosclerosis, aseptic osteonecrosis. Long-term consequences are also possible due to irreversible nerve damage: deafness, blindness, paralysis, imbalance.
Forecast
The prognosis is determined by the severity of the lesion of the nervous system by gas bubbles, as well as the timeliness of the therapy.
Prevention
Prevention of decompression sickness consists in careful observance of safety precautions and rules for working in compressed air. Employees are hired only after a medical examination, which in the future should be regular. People working at depth should lead a healthy lifestyle, do not abuse alcohol, and stop smoking.
After suffering decompression sickness, workers are suspended from deep-sea work in the following cases:
- severe course of the disease;
- the presence of residual effects;
- decompression sickness has occurred more than once.
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Elena Minkina Doctor anesthesiologist-resuscitator About the author
Education: graduated from the Tashkent State Medical Institute, specializing in general medicine in 1991. Repeatedly passed refresher courses.
Work experience: anesthesiologist-resuscitator of the city maternity complex, resuscitator of the hemodialysis department.
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
