Caisson disease (decompression sickness, CKD, caisson, diver's disease) is a disease caused by the rapid transition of a person from a medium with high pressure to a medium 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 among divers in violation of the rules for conducting deep-sea work (too fast ascent or prolonged stay in depth).
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 (securing bridge piers, building underwater tunnels). Workers passed through the lock into this cell, where they carried out the necessary work. To prevent flooding of the caisson, compressed air was introduced into it. After the working shift ended, the pressure was reduced to atmospheric. At the same time, many workers had severe pain in the joints, and some developed paralysis and even deaths.
Causes and Risk Factors
A certain amount of gas is dissolved in the blood and biological fluids of the human body, depending on the pressure of the gas mixture above the surface of the fluids. If the gas pressure above the liquid becomes greater than 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 release of previously dissolved gas from it. It is precisely this “boiling” of blood that is observed among divers with a rapid ascent to the surface, and it becomes the cause of decompression sickness.
People working in depth should lead a healthy lifestyle, not abuse alcohol, and quit smoking.
When working at depth, the breathing mixture to the divers is supplied under increased pressure corresponding to the pressure of the environment. For example, if the submariner operates 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 that of people on the surface. When surfacing, the hydrostatic pressure of the water decreases, and therefore the pressure of the respiratory mixture decreases, which leads to the formation of nitrogen bubbles in the blood. With a slow ascent, microbubbles of nitrogen with blood flow into the lungs, from where they are expelled through the alveolar walls with exhaled air. If the ascent is too fast, the nitrogen bubbles do not have time to be excreted by the lungs. Platelets and then other blood cells begin to attach to them, which leads to the formation of blood clots, which clog the vessels of the microvasculature. After some time, blood clots adhering to the walls of the vessels break away from them, leading to a violation of the integrity of the vessels, hemorrhages in the surrounding tissue.
Factors that increase the risk of developing decompression sickness are:
- violation of the regulation of blood circulation under water,
- age (the older the age, the higher the risk of decompression sickness),
- significant physical activity before or during a dive,
- hypercapnia - may be due to the presence of contaminants in the respiratory gas mixture, its economy,
- drinking alcohol before diving or immediately after surfacing.
If the victim is in a state of clinical death, they lay him on his back and immediately begin resuscitation.
What is decompression sickness
Divers' disease - this name still has this disease, since it manifests itself after it emerges from the depths to the surface. Caisson disease is a disease that occurs as a result of a decrease in the pressure of the gases inhaled by a person. Gases dissolved in the blood turn into bubbles. They begin to block blood supply, destroying cells and blood vessel walls.
CST is developing in those people whose professional activity is associated with work in high pressure. To normalize the state of the human body, a gradual and correct transition to normal pressure is necessary, which is not always observed. For this reason, compression occurs, which gave the name to this disease. It can lead to paralysis and even death.
Symptoms of caisson disease
The clinical picture of decompression sickness, depending on the degree of damage to the nervous system, is manifested by the following syndromes:
- decompression of peripheral nerves - observed with mild caisson disease, clinically manifested by neuralgia (pain along the affected nerve),
- decompression damage to the spinal cord - the latent period is short, the first symptoms of caisson disease are shingles in the chest area and impaired skin sensitivity of the limbs. Subsequently, the victims develop dysfunctions of the pelvic organs, spastic paralysis of the legs, and damage to the hands is noted much less frequently. With the untimely provision of specialized care, paralysis becomes irreversible,
- decompression damage to the brain - the duration of the latent period does not exceed several minutes. The victims experience anxiety, severe headache, adynamia, constant nausea and repeated vomiting, impaired consciousness from mild inhibition to deep coma,
- multiple decompression lesions of the nervous system - observed in about 50% of cases. The combination of neurological symptoms of a caisson disease is determined by the severity and localization of damage to the central and peripheral nervous system.
Caisson disease mechanism
Caisson disease is a blockage of blood vessels by a gaseous thrombus, which is based on nitrogen bubbles. Caisson disease occurs as a result of changes in the concentration of gases in body fluids. To understand the mechanism of the disease, it is necessary to recall Henry's law, which says that increasing pressure leads to a better dissolution of gases in liquids. Diving to the depths, the diver breathes compressed air. At the same time, nitrogen, which under normal conditions, does not enter the bloodstream of a person, under conditions of high pressure penetrates into the vessels.
When the external pressure during ascent begins to decrease, the gases escape from the liquid. If the diver rises to the surface of the water slowly, nitrogen manages to leave the blood in the form of small bubbles. With a quick rise up, the gas tends to get out of the liquid as soon as possible, but, not having time to get to the lungs, it blocks the vessels with microtubes. The vesicles attached to the vessels can come off together with pieces of vessels, which leads to hemorrhages. If nitrogen bubbles do not enter the vessels, but into the tissues, tendons or joints, an extravascular form of decompression sickness occurs.
At the prehospital stage, patients with caisson disease undergo oxygen therapy. Hospitalization is shown in a hospital equipped with a pressure chamber. Transportation by air is undesirable - this is due to the fact that at high altitudes, air bubbles in the body begin to increase in size, leading to a further deterioration of the condition.
The main treatment for decompression sickness is recompression. The patient is placed in a pressure chamber, where 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 (forms of decompression sickness, time elapsed since the first signs, the condition of the victim). In most cases, pressure is initially created in the pressure chamber, similar to immersion of 18 meters. Then it is reduced to normal gradually, over several hours, and in severe cases days.
Most often, the disease is observed in divers in violation of the rules for conducting deep-sea work.
While in the pressure chamber, the patient breathes pure oxygen through a nasal mask. It is periodically removed for 5-10 minutes in order to prevent oxygen poisoning.
Caisson disease prevention
An important point in the question of how to avoid decompression sickness is the observance of the rules of immersion and ascent:
- Before diving, it is necessary to reduce physical activity.
- Do not dive after drinking alcohol.
- Do not engage in those types of work that are associated with changes in atmospheric pressure, people with diseases of the cardiovascular system, diabetes, muscle and bone diseases.
- Lifting to the surface should be slow.
- For diving, you must use professional equipment.
Decompression sickness (decompression sickness, DCS) - a complex of changes that develop during the transition from high atmospheric pressure to normal, less often - from normal to low. Pathology got its name from the word "caisson", which means a camera created in the 40s of the XIX century and designed to work under water or in conditions of water-saturated soils. CST is considered an occupational disease of submariners and specialists working in caisson chambers; in some cases, it is diagnosed in pilots. In recent years, due to the wide distribution of diving, it is detected in other groups of the population. According to statistics, the incidence of the disease is 2-4 cases per 10,000 dives.
The main factor in the progression of decompression sickness is a too sharp change in pressure. As a result of environmental changes in the bloodstream, gas bubbles form, which can group together and cause blockage of blood vessels, destruction of tissues or, conversely, their excessive compression. As a result of this, blood clots form, which rupture the vessels and lead to their death. Bubbles with a blood stream can enter any organs of the human body and lead to a disruption in their normal functioning.
Predisposing factors to the occurrence of this disease are:
- sharp rise to the surface,
- immersion in too cold water
- the impact of stressful situations and fatigue,
- excessively high body weight
- submersible age category. It is believed that the older the person, the higher the likelihood of this disorder,
- flight a few hours after submersion in water,
- drinking before or after diving.
The risk group consists not only of divers, divers or miners working at depth, but also pilots who experience significant pressure drops when flying at high altitude.
Pathogenesis of decompression sickness
Regarding the pathogenesis of decompression sickness, gas theory is currently preferred. Its essence lies in the fact that the liquids in the human body, when immersed at great depths, are saturated with gases, mainly nitrogen. This is confirmed by Henry's law, which indicates that the higher the pressure, the better the solubility of gases in the blood
It is important to understand that the process of gas formation in the human body affects absolutely all fluids, without exception. For this reason, diseases of the spinal cord and bone marrow, lymphatic system, joints, etc. This is especially noticeable in the respiratory system, since with compression a person begins to cough, sneezing especially intensively. Nitrogen vesicles are easily detected by morphological studies.
Depending on the intensity of the manifestation of symptoms, there are several stages of the course of caisson disease:
- mild - manifests itself as slight pain in the joints, muscles,
- moderate - signs are dizziness, nausea, temporary loss of vision,
- severe - convulsions (a substance located in the spinal cord is involved in the pathogenic process), a systemic speech disorder,
- lethal - the symptoms develop against the background of acute heart failure or circulatory disorders of the brain.
In addition, there are two types of disease:
- first - lymph nodes, skin, muscles, joints are involved in the process,
- the second - damage to the brain and spinal cord, respiratory and cardiovascular systems is observed.
Causes of decompression sickness
As mentioned above, the causes of decompression sickness are associated with the gases formed in the blood. Caisson's disease occurs when blood flow changes with an abnormal or rapid ascent to the surface. Long high-altitude work and hypothermia can also cause the disease, as well as dehydration, which helps slow down blood circulation due to gas blockages. Incorrect use of breathing equipment during operation is another feature that distinguishes the box.
Classification of decompression sickness
Typically, 2 types of decompression sickness are distinguished. Type I, with involvement of the muscles, skin, and lymphatic system, is moderate and generally not life threatening. Type II is much more serious, sometimes life-threatening and damages various organ systems. The spinal cord is particularly vulnerable; other damaged areas include the brain, respiratory (e.g., pulmonary emboli), and circulatory systems (e.g., heart failure, cardiogenic shock). “Homotomy” means local pain in joints and muscles as a result of decompression sickness; the term is often used as a synonym for any component of this disease.
Differential diagnosis of gas embolism and decompression sickness
The consequences of decompression sickness are individual for each person and are manifested depending on the form and severity of the disease, as well as on the timeliness of the treatment started. Possible complications may include:
- heart and respiratory failure,
- osteoarthrosis - a violation of the articular cartilage,
- multiple lesions of the gastrointestinal tract,
- inflammation of the optic nerve.
A fatal outcome occurs with a severe course of the disease, as well as due to the failure to provide medical care.
The acute form of caisson disease is diagnosed on the basis of patient complaints, anamnestic data and the results of an external examination. On radiographs, gas bubbles can be found in the joints, muscle tissue, fascia, tendon sheaths. To determine the state of the central nervous system, tomographic studies of the spinal cord and brain are prescribed. Confirmation of the diagnosis is the improvement of the patient's condition during recompression. The examination program for the development of complications is determined by the nature of the alleged pathology, and may include ECG, echocardiography, radiography, ultrasound, MRI and CT of various organs.
Forecast and Prevention
The outcome of CKD is determined by the severity of the lesion and the time at which recompression begins. 80% of patients have a full recovery. Lethal outcomes are quite rare, usually with an emergency rise or lack of specialized care.Prevention of decompression sickness includes the use of high-quality equipment for diving and professional work at depth, strict observance of lifting rules, taking into account data from specially designed tables, regular medical examinations, and the exclusion of factors that increase the risk of CST. Preventive measures also include the establishment of a sufficient time interval between the first and subsequent dives or flights by air, limiting the time spent in high pressure conditions for divers and caisson workers.
For the body of each person, the consequences of decompression sickness can be expressed in different ways. They depend on the severity and form of the disease. Timely provided medical care also plays an important role, because, as already mentioned, if she does not keep up to date, then a fatal outcome can occur. Among other things, one can also distinguish such consequences of the disease:
- heart failure,
- inflammation of the optic nerve,
- respiratory failure
- disorders in the digestive tract,
- osteoarthrosis, etc.
What is decompression sickness?
Caisson disease is a special condition of the body that occurs as a result of a transition from a medium with normal atmospheric pressure to a medium with high pressure. The people call this pathology a "professional" disease, which in most cases is subject to divers, as well as all scuba diving enthusiasts.
Another name for medical directories is “decompression sickness,” or DCB for short. Divers among themselves call it "caisson". According to statistics, decompression sickness develops in 2-4 cases per 10,000 dives.
In most cases, decompression sickness develops among divers and scuba divers.
Symptoms and classification of decompression sickness
The disease is classified by severity:
Each stage of the disease is characterized by certain symptoms:
The mild form is joint, muscle, bone pain, nerve pain, which is caused by irritation of the nerve endings, as well as pressure on the nerve endings, which is formed by gas bubbles. As a result, hypoxia develops.
The form of moderate severity is dizziness, nausea, vomiting, increased sweating, headache, digestive upset, disturbance of the organs of vision, gas accumulation in the intestines. The main symptom is spasm of the retinal artery.
Severe form - damage to a substance that is in the spinal cord. The white matter located in the spinal cord dissolves large volumes of nitrogen. In the future, a person develops lower spastic paraparesis. Vomiting, headache, aphasia are also noted.
The lethal form develops due to an extensive blockade of blood circulation in the lungs, also on the basis of acute heart failure or against the background of total blockade of blood circulation in the main centers of the medulla oblongata.
The risk of developing CKD is increased under the following conditions:
- water temperature is too low
- the rise from depth is too sharp
- the diver is in a state of stress, fatigue, intoxication, or took alcohol after climbing,
- soon after the dive, the diver flies.
In addition to the above reasons, the risk of decompression sickness due to atmospheric pressure drops is very high for people with a body weight exceeding the norm, and elderly people. It is believed that the older the person, the more likely the development of such a violation.
On a note. A caisson can arise not only among divers and divers, but also among miners or pilots who also have to endure sudden pressure surges.
According to the severity of violations, the "box" can be:
- light, when gas bubbles damage only the nerve endings,
- medium, characterized by damage to arteries and autonomic disorders, resulting in serious digestive upsets,
- severe, arising from a total defeat of nerve endings, proceeding against the background of paresis of the legs,
- lethal, which is characterized by vascular blockade and severe damage to the respiratory system and brain centers.
In the latter case, it is almost impossible to help the victim, and death occurs as a result of cardiac arrest or respiratory arrest.
A heavy "box" has such manifestations:
- convulsive attacks
- pain in the chest
- paralysis and paresis of limbs,
- impaired speech function,
- deterioration in the work of the respiratory organs and asthma attacks.
The lethal form that occurs against the background of multiple injuries is accompanied by loss of consciousness and respiratory function disorders.
Important! If signs of CST are detected, you must immediately call an ambulance, and before the arrival of specialists, take measures to provide emergency care. The outcome of the disease largely depends on how timely they were implemented.
If you find the symptoms that accompany the mild form of the violation, namely itching on the skin, weakness and fatigue, you need to do the following:
- lay the victim face up,
- to straighten legs and arms
- drink non-carbonated water.
These manipulations can be performed if the patient is conscious. In situations where the victim periodically loses it, the fluid is strictly contraindicated, and it is better for the patient to sit and not lie.
If a person is unconscious, he will need to be turned on his left side, bending his right leg in a knee. This posture will help prevent fluid from entering the airways if vomiting occurs.
When there are obvious signs of clinical death, before the arrival of the doctors, it is necessary to carry out the necessary resuscitation measures, laying the person on his back. In this situation, artificial respiration and indirect heart massage are indicated.
Such a violation threatens with the following complications:
- joint damage
- heart disease
- respiratory failure
- digestive problems
- damage to the optic nerve.
As the long-term consequences arising against the background of the "caisson", there are loss of vision and hearing, impaired coordination of movements and paresis of limbs.
Attention! If a person who has undergone CKD has any residual symptoms of the disease, he is strictly forbidden to return to work or a hobby associated with diving in underwater space or air travel.
To minimize the risk of CKD, the following recommendations must be followed when in depth:
The same rule applies to pilots who need a break between flights at least 24 hours.
You should not risk it and make a deep dive in the presence of the following conditions:
- diabetes mellitus
- diseases of muscles, bones and joints,
- disturbances in the work of the heart,
- alcohol or drug intoxication.
Compliance with the listed recommendations and prohibitions will significantly reduce the risk of decompression sickness. And knowing how to provide first aid, you can save someone's life.
Caisson Disease Risk Factors
The only risk factor for decompression sickness is a sudden drop in pressure. It occurs as a result of:
- Too fast rise to the surface after deep diving. The risk increases with increasing diving depth,
- Fast rise to high altitude with low,
- Sudden change in pressure
- Long dive time
- Multiple dives in one day
- Flying a plane after scuba diving,
- Scuba diving in cold water,
With increasing pressure, the solubility of gases in liquids (in this case in blood, lymph, synovial and cerebrospinal fluids) increases, while with a sharp decrease in pressure, the gases dissolved in the liquid are released in the form of bubbles, which tend to group and block, destroy, squeeze vessels.
A breakthrough of the vascular wall leads to hemorrhages in the tissue of organs. Bubbles can also cluster and cause gas embolism.
During the formation of extravascular vesicles (mainly in hydrophilic tissues of joints and ligaments), serious damage to internal organs can occur due to compression of muscle fibers and nerve endings by the vesicles.
The risk group now includes not only divers and working caissons, but also pilots experiencing pressure drops in flights at high altitudes, and astronauts using suits that maintain low pressure when going into outer space.
Factors that provoke the development of decompression sickness:
· A sharp rise to the surface from depth without stopping,
· Air flight after a deep sea dive,
Violation of the regulation of blood circulation at a depth (under water),
· Hypothermia in high blood pressure,
· Age-related changes (less effective blood flow, weakened cardiovascular and respiratory systems),
· Dehydration (slowed blood flow contributes to the formation of "nitrogen barricades"),
· Physical activity during or before a dive,
Drinking alcohol immediately before or after diving,
· Overweight divers,
· Hypercapnia (increased resistance to breathing, physical exertion, breath holding to save the respiratory mixture, contamination of mixtures).