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Compressed-air disease


The decompressive, or caisson disease, in abbreviated form — DKB (on a slang of submariners — a kessonka) — the disease happening, mainly, because of bystry pressure decline of the inhaled gas mix as a result of which the gases  (nitrogen, helium, hydrogen — depending on respiratory mix) dissolved in blood and body tissues begin to be emitted in the form of bubbles in blood of the victim and to destroy walls of cells and blood vessels, to block a blood stream. At a severe form the compressed-air disease can lead to paralysis or death.

Symptoms of the Compressed-air disease:

Sometimes the compressed-air disease is confused to arthritis or injuries. The last are followed by reddening and swelling of an extremity; arthritis, as a rule, arises in pair extremities. Unlike a compressed-air disease in both cases the movement and pressing the damaged place strengthen pain. At a severe form of a compressed-air disease vitals and systems of a human body are surprised: head and spinal cord, heart, acoustic organs, nervous system and so forth. According to medical statistics of the USA, nearly 2/3 victims of a compressed-air disease had this or that its neural form. Most often the spinal cord suffers. Damage of a spinal cord results at disturbance of its blood supply from education and accumulation of bubbles in surrounding fatty tissues. Bubbles block the blood stream feeding nervous cells and also put upon them mechanical pressure.

Owing to a special structure of the arteries and veins supplying a spinal cord, disturbance of blood circulation in them is caused very easily. The initial stage of a disease is shown in so-called "girdle pains", then joints and extremities grow dumb and refuse, and paralysis develops — as a rule, it is paralysis of a lower body. As a result of it, also internals, for example a bladder and intestines are affected. Damage of a brain is caused by disturbance of its blood supply as a result of blocking of vessels and formation of extravasated bubbles in brain fabric. The brain swells and presses on a cranium from within, causing a headache. Painful symptoms are followed numbness of extremities (either both right, or both left), by disturbance of the speech and sight, convulsion and a loss of consciousness. As a result any vital sign can seriously suffer (for example, functions of sensitive bodies — sight, hearing, sense of smell, taste, perception of pain and touch) that is soon shown also in clinical signs. Damage of the think-tank controlling any of these feelings leads to loss of specific function. Disturbance of motive function, coordination and the movement, has catastrophic effects, and one of the most frequent — paralysis. Autonomous activity of biological systems, including respiratory, cardiovascular, urinogenital, etc., can be also broken, and it involves a serious illness or death.

Decompressive damage of acoustical and vestibular bodies meets at the deep-water scuba divers using special gas respiratory mixes more often. The disease is followed by nausea, vomiting, loss of orientation in space. These symptoms of a compressed-air disease should be distinguished from similar, caused by a barotrauma.

Hit of bubbles from an aorta in the coronary arteries supplying with blood a cardiac muscle leads to disturbances of cordial activity which final can be a myocardial infarction. The pulmonary form of a compressed-air disease occurs very seldom and only at the submariners plunging on considerable depths. A set of bubbles in a venous blood block blood circulation in lungs, complicating gas exchange (both oxygen consumption, and nitrogen release). The symptomatology is simple: the patient feels breath difficulty, suffocation and stethalgias.

Reasons of the Compressed-air disease:

    * Disturbance of regulation of blood circulation under water.
    * Aging of an organism is expressed in weakening of all biological systems, including cardiovascular and respiratory. It, in turn, is expressed in decrease in efficiency of a blood-groove, cordial activity, etc. Therefore the risk of DKB increases with age.
    * Overcooling of an organism therefore the blood stream, especially in extremities and in a body blanket, is slowed down that favors to emergence of a compressed-air disease. It is rather simple to eliminate this factor: at immersion it is necessary to put on rather warm diving suit, gloves, boots and a helmet.
    * Organism dehydration. Dehydration is expressed in reduction of volume of blood that leads to growth of its viscosity and delay of circulation. Same creates favorable conditions for formation of nitric "barricades" in vessels, the general disturbance and a stop of a blood-groove. Organism dehydration during scuba diving is promoted by many reasons: sweating in a diving suit, moistening of dry air from an aqualung in an oral cavity, the strengthened uropoiesis in the submersed and cooled state. Therefore it is recommended to drink as much as possible water before immersion and after it. Fluidifying of blood reaches acceleration of its current and increase in volume that positively affects process of a conclusion of excess gas of blood through lungs.
    * Physical exercises before immersion cause active formation of "silent" bubbles, uneven dynamics of a blood-groove and education in circulatory system of zones with high and low pressure. Experiments showed that the quantity of microbubbles in blood considerably decreases after rest in lying situation.
    * The exercise stress during immersion leads to increase in speed and irregularity of a blood-groove and, respectively, to nitrogen absorption strengthening. Heavy physical exercises, lead to postponement of microbubbles in joints and prepare favorable conditions for development of DKB at the subsequent immersion. Therefore it is necessary to avoid big exercise stresses to, during and after immersion. Especially as exercise stresses increase sugar consumption that leads to heating of fabrics and to increase in speed of release of inert gas — to increase in a gradient of tension.
    * Divers with an excess weight are subject to bigger risk "to pick up" a compressed-air disease (in comparison with submariners with a normal constitution) as in their blood the content of fats which, owing to the water repellency, strengthen formation of gas bubbles is increased. Besides, lipids (fatty tissues) most well dissolve and hold in themselves inert gases.
    * One of the most serious provocative factors of DKB is the hypercapnia at the expense of what acidity of blood sharply increases and, as a result, solubility of inert gas increases. The factors provoking a hypercapnia: an exercise stress, the increased respiratory resistance and breath holding for "economy" of DGS, existence of pollution in the inhaled DGS.
    * Alcohol intake before and after immersion cause severe dehydration that is the unconditional factor provoking DKB. Besides molecules of alcohol (solvent) are those "centers" which cause adhesion of "silent" bubbles and formation of the main gas body — a macrobubble. The main danger of alcohol intake — in its bystry dissolution in blood and the approach of morbid condition following it bystry.

Treatment of the Compressed-air disease:

Any medical care begins with check of the general state, pulse, breath and consciousness, and also keeping of the patient in heat and an immovability. To give first aid to the victim of DKB, it is necessary to define its symptoms. Among them distinguish "soft", such as strong unexpected fatigue and skin itch which are eliminated with pure oxygen, and "serious" — pains, disturbance of breath, the speech, hearing or sight, numbness and paralysis of extremities, vomiting and a loss of consciousness. Emergence of any of these symptoms forces to assume emergence of a severe form of DKB.

If the victim is in consciousness and it shows only "soft" symptoms, it is better to put it on a back horizontally, without allowing the pose complicating a blood stream in any extremity (crossings of legs, a podkladyvaniye of hands under the head, etc.). The person with the affected lungs most comfortably feels in a motionless sedentary pose which saves him from suffocation. At other forms of a disease of a sitting position it is necessary to avoid, remembering positive buoyancy of nitric bubbles.

The submariner with serious symptoms of a disease it is necessary to put differently. As victim in unconsciousness can throw up (and at a dorsal decubitus emetic masses can get into lungs), to prevent an overshoot of respiratory tracts emetic masses, it is put on the left side, bending the right leg in a knee for stability. If breath of the victim is broken, it is necessary to put the patient on a back and to make an artificial respiration, and if necessary — an indirect cardiac massage.

After to the patient helped to adopt the correct provision, it should provide breath with pure oxygen. It is the main and most important reception of first aid until as you will transfer the specialist who was injured in hands. Breath by oxygen creates favorable conditions for transportation of nitrogen from bubbles in lungs that reduces its concentration in blood and tissues of a body. For first-aid treatment sick DKB uses the special cylinders with the compressed oxygen supplied with the regulator and a mask with supply of oxygen of 15-20 l/min. They provide breath with almost absolute oxygen, and the transparent mask allows to notice emergence of vomiting in time.

Transportation of the patient in a pressure chamber. Movement by air transport should be avoided as at big heights bubbles will increase in volume that will aggravate a disease. Hemorrhages at the most severe forms of a compressed-air disease lead to an effluence of blood plasma in fabric, and this loss needs to be compensated. The patient with "soft" symptoms force to have a glass of water or any soft not carbonated drink each 15 min. You remember, however, that acid drinks like orange juice can make sick and vomiting. To the person who is staying half-conscious or periodically fainting, it is not recommended to drink.

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