ALTITUDE SICKNESS, SEA SICKNESS, DECOMPRESSION SICKNESS : DECOMPRESSION SICKNESS - etiology, pathogenesis, symptoms and course of, recognition, prediction and prevention
When excessively rapid decompression, the body is in a state of considerable supersaturation gases (mainly nitrogen). The amount released when this gas may be such that there is a gas embolism. Last, causing anoxia and asphyxia blocked tissue, can result in complex vasomotor reaction, prestas with hemorrhages by diapedesis, transsoudata plasma and blood clots. In extreme cases may be irreversible changes in the vessel stasis.
Embolism may disappear spontaneously or under the influence of therapeutic interventions; an incorrect treatment in severe cases embolism gives residual changes leading to disability; sometimes death occurs. Fast enough to eliminate aaaembly in the Central nervous system leads to the formation in it of foci of softening. On this basis, in the spinal cord develops coffered Milos; in the vestibular apparatus - permanent magerovsky syndrome. In vessels, the formation of aerodromes that determine primary chronic process localized in the bone and joint system, where heart attacks come in the future microtiterplate; on this basis develop a deforming osteoarthrosis. The same process probably takes place in the heart where the evolving infarction (miocardio-fibrosis).
Conditions favoring disease:
a) adverse temperature effects due to the increased conductivity and high humidity of the compressed air;
b) inadequate air exchange in the caisson, what has caused the violation of the heat economy of the body;
C) the use of the Valsalva technique during sluicing in the caisson;
g) violation in dietetic and flatulence.
Depending on the localization, size and number of gas emboli, acute manifestation of the disease can be mild, moderate, severe and fatal form.
A mild form characterized by a long latency period (2 - 3 - 6 hours or more), easy reversibility of symptoms and rapid recovery without residual effects. The most frequent osteoarthri. Apart from the pain, palpation sometimes occurs crepitus in the joint, occasionally swelling, effusion, the noise of friction during passive movement; sometimes on the affected limb are observed at first pale, then cyanotic spots or small skarlatinopodobnaya rash, often little pronounced.
Neuralgia is often the trigeminal nerve and on the limbs. Skin lesions occur in the form of itching, marbling of the skin (depends on the blockage of skin veins) and, finally, subcutaneous emphysema.
Form moderate characterized by the possibility of residual phenomena of limited value; it includes magerovsky syndrome (transient), gastrointestinal and ocular lesions. The latent period is shorter (2 ½ hours); prodromal phenomena in the form of a large fatigue. When meneruskan syndrome (dizziness, tinnitus and other)caused by aeroembolism labyrinth vessels, as harbingers marked heaviness and aches in the head; in case of failure to eliminate aeroembolism in a fairly short period of time takes a chronic course. Gastrointestinal lesions - abdominal pain, usually in the epigastric region, often nausea, vomiting, sometimes with blood, bile; the abdominal wall tight, palpation is difficult, if tympanic percussion sound. Ocular lesions are quite rare; they can be in the form of aeroembolism in the retina (with transient blindness), vessels of the optic nerve (atrophy) and lens (with the rapid development of cataracts).
A severe form has a short latent period (10 to 30 minutes) with prodromal symptoms in the form of sharp adynamia. Spinal lesions on the grounds of aeroembolism mainly in the lower third of the thoracic spinal cord (lower paraplegia or prepares). Paralysis usually spastic, rarely dull; anuria, constipation; increased tendon reflexes; sometimes poor coordination; trophic disorders in the skin. In mild cases only motor weakness. Often as a precursor to fornicate, as an accompanying symptom - marbling of the skin. Regionalna-cerebral lesions caused by aeroembolism in certain, limited areas of the brain are expressed in Hemi-monoplegia, aphasia or hindered speech, Alexs, mental disorders; occasionally phenomena of irritation of the meninges. Regionalna-pulmonary lesions on the grounds of aeroembolism in limited areas of the lung with heart attacks (most often in the lower lobes, mainly on the right) give transient disorders: tightness in the chest, sudden pain in the side or under the sternum, coughing, shallow rapid breathing, seizures asthma, asthmatic status, often haemoptysis, with percussion - dulling in the nidus, when listening to - a small musical sounds. The skin on the face and the mucous membranes of cyanotic. Coronary lesions (aaaembly in the branches of the coronary system: dizziness, retrosternal pain, tightness in the chest, predserdna depression, irregular heartbeat, pale skin. Aeroembolisms collapse is caused massive aeroembolism, causing insufficient blood flow to the heart and is accompanied by the following phenomena: a twinkle in the eyes, sometimes intense headaches; the fall of the vascular and muscle tone and turgor of the skin; frequent, shallow and irregular breathing, sometimes Cheyne-Stokes; tachycardia, sometimes imbricaria. Deaf heart sounds, pulse, soft, weak, often filiform, often vomiting. Deathly pale color of skin, sometimes dark red spots on the skin, disappearing when pressed, often subcutaneous emphysema different prevalence.
Deaths due to:
1) aeroembolism all or almost all of the small circle of blood circulation that is accompanied by severe shortness of breath, chest pains, and sudden cyanosis; rapid loss of consciousness and death;
2) the accumulation of gas in the right heart, which leads to acute liver enlargement, swelling of neck veins, filiform pulse, cold, clammy sweat, sometimes causes cardiac asthma and pulmonary edema;
3) aeroembolism in the field of vital centers in the medulla with a severe cyanosis and rapid death.
Perhaps the combination of different localizations of aeroembolism. The disease, caused by aeroembolism, always acute, short (from a few hours to 2 - 3 days). Aaaembly in the Central nervous system, causing it irreversible changes, gives secondary chronic process:
1) in the spinal cord - the miliary myelomalacia; clinically - coffered Milos (spastic, sometimes spasticity-pateticheskaja gait, impaired reflexes Achilles tendon and patello, sharp Babinski phenomenon and Rossolimo, absence of reflex from the cremaster, impotence);
2) in the inner ear - permanent magerovsky syndrome. Coffered deforming osteoarthrosis localized in the femoral, humeral, tibial; most often affects diaphyse and epiphyses, much less only the epiphyses. Symptoms occur only after a number of years since the last stay under pressure. The course may be asymptomatic, especially in the defeat of one divisov. First, the awkwardness in the limbs, more restriction of its use, sparing; further lameness, derevyannye, dull pain, lifting the pelvis on the affected side of the lower limb, compensatory scoliosis.
Recognition of acute cases not encounter any difficulties, based on subjective and objective symptoms in combination with the fact of a previous stay under pressure.
If osteoarthri when there are no objective symptoms, valuable results can be expected reception Konchalovsky, which reveals invisible skin rash. Slight marbling of the skin may become noticeable when the Valsalva technique. When meneruskan syndrome diagnostic value may be a symptom Romberg, always positive. In the gastro-intestinal lesions may be necessary differential diagnosis for acute abdomen. Crucial to stay under pressure.
Prediction in light form is always positive, in other cases - depending on the speed of application recompression and other treatments.
1) compliance length of stay under pressure and decompression, established by the legislation;
2) application of the rational method decompression;
3) prevention of pressure drop during decompression more than 0.02 ATM for 3 - 4 seconds to avoid risky enhance internal-lung pressure;
4) compliance with temperature standards established by law, in caissons and especially in the gateways during decompression and after it;
5) filing with the caisson sufficient amount of compressed air (2 to 3 exchange 1 hour in the working chamber);
6) purification of compressed air from polluting his oils and their vapors;
7) during decompression oxygen or synthetic air (oxygen-helium);
8) exercise or rubbing of the feet and hands;
9) smooth, quiet breath; to avoid delays and to prevent cough, sneeze, blow your nose;
10) after decompression shower or bath, inside 2 cups hot natural tea or coffee;
11) to avoid a heavy meal before descending under pressure and soon after leaving the caisson;
12) to exclude from food products that cause abundant flatulence, not to drink under pressure fizzy and carbonated beverages;
13) careful medical screening on the current schedule of medical contraindications and regular medical recertification;
14) for violation of the norms decompression and other adverse phenomena prophylactic recompression when the pressure in ½ - ¾ working pressure.
The primary method for all cases of acute over - recompression (pressure recovery in a medical or therapeutic gateway)should be applied with a possible speed; the pressure rises to the level at which disappear or at least diminish the symptoms (usually ¾ from the pressure at which the work was performed); duration recompression 30 minutes - 2 hours.
Decompressed (reduction of pressure in the treatment chamber) at the rate of not less than 10 minutes per 0.1 ATM, in severe cases, 14 to 18 minutes. The essence of the method is the compression of emboli to the size at which stops the blockage of blood vessels (according to the law of Boyle-Mariott), as well as the reabsorption of gas from them.
Cardiovascular drugs: cardiazol, Keramin, strophanthin, caffeine (injection or inside), camphor, in mild cases diuretin, Lily of the valley drops; adrenaline, simpathy, ephedrine, strychnine, for the rapid expansion of blood vessels Natrium nitrosum and amyl-nitrite. To fight blood clots and to reduce the viscosity of the drink (tea, coffee), in severe cases, injections of physiological solution (with gum-Arabicas), glucose, blood plasma. For excitation of cutaneous respiration - lungs diaphoretic (decoction of chamomile, elderflower, Linden). Pain is only in extreme cases (pantopan). The use of medicinal substances - mainly during recompression and decompression, and therefore should be preferred prescription of drugs inside.
Physiotherapeutic methods: local heat (heating pad, poultices, dry air boxes) if osteoarthri, neuralgia, myalgia; total heat (dry air, water baths) - under the same lesions and skin irritation; diathermy - under the same lesions and meneruskan syndrome, spinal paralysis and regionalna-cerebral lesions; electrotherapy (neuralgia and Milos).
Oxygen therapy is to accelerate the reabsorption of gas from emboli, reducing the degree of saturation of the tissues and reduce the duration of decompression, suitable during recompression, but, due to oxygen toxicity, apply it in the period of decompression at a pressure not higher than 1.8 ATM; contraindicated in lesions of the Central nervous system and in the presence of angiospastic phenomena; requires special equipment. Regular inhalation of oxygen to appoint regionalna-pulmonary lesions to accelerate the arterialization of the blood (short time during recompression).