COOLING OF THE ORGANISM

From Big Medical Encyclopedia

COOLING OF THE ORGANISM — disorder of functions of an organism as a result of action of low temperature.

Distinguish the general and local cooling (see. Freezing injury ), however in practice the general cooling is often combined with local, and local impact of cold can cause the expressed phenomena of the general cooling.

P. M. Starkov (1957), E. V. Maystrakh, etc. (1962) understand the impact of cold which is not followed by decrease in body temperature as the general cooling is lower normal (for the person — not lower than 35 °). Temperature drop of a body is lower than this level (hypothermia) if it is caused by impact of cold as disturbing factor of the environment, demonstrates that compensatory mechanisms of thermal control do not cope with its destroying action; in this case speak about overcooling of an organism. G. A. Akimov et al. (1977) understand as freezing of an organism patol, the hypothermia which is followed by dangerous disorder of functions of an organism up to his death. The term «freezing» concerning a complete organism is conditional since, according to E. V. Maystrakha (1962), death comes at the body temperature considerably exceeding 0 ° when true freezing with formation of ice is impossible. So, decrease in temperature in a rectum to 17 — 18 ° is usually deadly to the person, to 20 ° — is almost irreversible, to 25 ° — it is very dangerous.

In addition to O. of the lake as patol, a factor there is a cooling physiological, observable at nek-ry hematothermal animals during winter hibernations (see) and the artificial deliberate cooling in the conditions of blockade of mechanisms of thermal control and artificial maintenance of functions of an organism applied in a wedge. to practice (see. Hypothermia artificial ).

The etiology

Cold as a harmful environmental factor exerts adverse impact on an organism and production activity of the person. Especially value of this factor in connection with development of big territories of Far North and Antarctica, swimming in high latitudes, flights increased in a stratosphere and space. However overcooling and freezing of the person are possible not only in extreme climatic conditions, but also in zones with temperate and warm climate, including and at above-zero temperature.

Speed and depth of cooling, in addition to force and time of influence of a cold factor, depend on a condition of an organism and conditions, in to-rykh it is. Resistance of an organism to cooling decreases at physical exhaustion of the person, starvation, alcoholic intoxication, blood loss, shock, injuries and diseases. The age also matters — at old men and children the resilience to cooling is reduced. Very essential factor promoting cooling is alcoholic intoxication, at Krom in connection with expansion of peripheral vessels perception of cold is weakened and even disappears, and heat waste increases. Overcooling occurs at the increased air humidity, strong wind, especially quicker if the person is in the light, close or got wet clothes when the thermolysis sharply increases. The person at hit in water is especially quickly cooled; freezing is possible even at rather high temperature. So, at water temperature 15 ° the person can survive no more than 6 hours, at water temperature 1 ° — only 30 min. V. A. Beeches (1977) on speed, about a cut cooling in certain conditions can lead the person to death, distinguishes an acute, subacute and slow form O. of the lake. At an acute form death comes within 1 hour of stay of the person in water with a temperature of 0 — 10 ° or under the influence of moisture and cold wind at exhaustion of an organism. At a subacute form death occurs during less than 4 hours of influence of a cold air in combination with the moistening and factors weakening an organism. At a slow form death comes after 4 hours of influence of a cold factor (cold air) in the conditions of protection of a body clothes or snow weight.

Mass defeats in result of cooling were observed during wars, accidents and natural disasters. So, e.g., N. Korsun (1937) reports that during Saraka-myshsky operation in 1914 the Turkish case within one night lost frozen more than 10 000 people.

The pathogeny

of the lake is O. a consequence of disturbance of a heat balance and develops when in an organism thermolysis (see) exceeds heat production (see). Cold — a strong irritant therefore cooling of a hematothermal organism is followed by the expressed functional, metabolic and biophysical changes. Many of them are studied by hl. obr. in an experiment on animals. About O.'s degree of the lake usually judge by decrease in rectal temperature, edges are reflected by a condition of a heat balance of deep body tissues.

In the course of O. islands distinguish phases of compensation and a decompensation of thermal control. In a phase of compensation thermoregulatory reactions of an organism have reflex, adaptive, protective character and are directed to the prevention of decrease in body temperature, on the one hand, by reduction of a thermolysis, and with another — increases in heat production. Reduction of a thermolysis is reached by the termination of sweating, a spasm of blood vessels of skin and muscles, reduction of a blood-groove in them. Heat production amplifies due to increase in a metabolism. Important factors of thermogenesis are the cold muscular shiver and increase in a tone of muscles. In this phase the number of cordial reductions increases, the ABP raises, the minute volume of heart and breath, concentration of glucose and free fat to - t increase in blood, the maintenance of a glycogen in hepatic cells and muscles decreases. Oxygen consumption increases by 5 — 6 times. In an experiment on animals it is established that at O. the lake in a phase of compensation of thermal control observes strengthening of electric activity of a cerebral cortex, secretions of thyritropic and adrenocorticotropic hormones by a hypophysis, 17 oxycorticosteroids and adrenaline adrenal glands, increase in viscosity of blood, increase in contents in it in erythrocytes and leukocytes. Thus increase funkts, activities of the main systems of an organism is characteristic of a compensatory phase O. of the lake.

In a phase of a decompensation of thermal control balance between heat production and a thermolysis is broken, the thermolysis and therefore the state patol, hypothermias develops prevails. At the same time the tendency to oppression funkts, activities of an organism and to decrease in metabolic rate is accurately traced. These changes develop against the background of a diskoordination of functions of bodies and systems. In process of deepening of a hypothermia there occurs braking of functions of a cerebral cortex, and then the subcrustal and bulbar centers. Quickly arising drowsiness deprives freezing opportunities actively to fight against further cooling.

At temperature drop of a body to 33 — 30 ° peripheral vessels extend, cordial reductions become more rare, the ABP decreases, the minute volume of blood decreases, pressure in system of a portal vein increases. The hyperventilation of lungs is replaced by the progressing reduction of minute volume of breath, a cut becomes rare and superficial. At the same time decreases r02 in fabrics, oxygen consumption by an organism decreases approximately by 5% for each degree of decrease in body temperature; the cold shiver disappears, however a superactivity of various muscular groups is defined on EM G. In cells of a liver and in muscular tissue the maintenance of a glycogen sharply decreases. If the organism is in a condition of overcooling within several hours, then the hyperglycemia is replaced by a hypoglycemia, the diuresis is sharply oppressed, in urine glucose and protein appear.

At patol, hypothermias the hypoxia as a result of disorder of breath and blood circulation (braking of the respiratory and vascular centers, spasms of respiratory muscles, bradycardia) develops. Fabric hypoxia (see) it is aggravated also with disturbance of microcirculation owing to decrease in a tone of vessels, delay of a blood-groove and deterioration in rheological properties of blood (a condensation, increase in viscosity, increase in number of uniform elements and concentration of hemoglobin).

Besides, in process of decrease in body temperature the curve of dissociation of oxyhemoglobin moves to the left therefore eliminating of oxygen in fabrics is complicated. All this promotes deepening of a hypoxia, accumulation milk to - you and to emergence metabolic acidosis (see). At the same time the need of fabrics for oxygen considerably decreases in connection with decrease in metabolic rate in process of development of a hypothermia.

Extent of functional and metabolic disturbances during the overcooling of a gomoyotermny organism is in direct dependence at most of a cold factor and duration of its influence. At rapid cooling power reserves of an organism are less exhausted, duration of air hunger of fabrics is shorter, however frustration of cardiovascular system are more expressed. Slow overcooling can be followed by the hypoglycemia which is a symptom of exhaustion of carbohydrate resources of an organism.

Pathological anatomy

Morfol. changes at O. of the lake are shown by a plethora of internals, a head and spinal cord and their covers, hematencephalons, Interalveolar partitions and a mucous membrane of a stomach, small focal necroses in internals, a fluid lungs, exhaustion of stocks of a glycogen in cells of a liver and other bodies.

The apnoea, fibrillation of ventricles of heart, an asystolia, a collapse are the most frequent causes of death during the overcooling of an organism. The apnoea comes owing to cold oppression of the bulbar centers. It occurs at the kept cordial activity, especially at freezing at preferential cooling of the head. Level of decrease in rectal temperature at the person at the same time is definitely not established. In an experiment at cats and dogs breath stops at a rectal temperature 24 — 19 °. Fibrillation of ventricles of heart at the person can arise at a temperature from 28 to 24 ° both during the cooling, and during the warming. The hypoxia of a myocardium, hyper-katekholaminemiya, jumps of pH of blood and increase in a gradient of Sa / To in a myocardium is the reason of fibrillation. The asystolia is observed rather seldom in cases when initially there were neither apnoea, nor fibrillation of ventricles of heart. The collapse is a consequence of oppression of function of the spinal vascular centers during the cooling preferential of area of a backbone (stay in a cold water, a long time in situation on spin on ice).

A clinical picture

According to V. A. Bukov (1977), in a wedge, O.'s current islands distinguish four stages: compensatory, adynamic, soporous and coma.

Victims are usually excited in a compensatory stage and complain of a fever. Lips of a tsianotichna, integuments are pale, cold to the touch, there is a symptom of «goosellesh», the muscular shiver, an asthma, tachycardia, increase in the ABP, increase of an urination are noted. Temperature in a rectum higher than 35 °.

In an adynamic stage consciousness is kept, however the victim is slowed down, sometimes eyforichen, complains of a headache, dizziness, weakness. The adynamia, decrease in a tone of muscles, oppression of tendon jerks are noted. Pupils of usual size. Breath is not broken. Depending on degree of a hypothermia pulse of normal rate or is slowed down to 40 blows in 1 min., is significantly not changed the ABP, cardiac sounds are muffled. Nek-ry victims are capable to eat food independently. Temperature in a rectum 35-30 °.

In a soporous stage the general block, slackness, drowsiness up to a condition of a sopor is noted, sometimes euphoria, dysmnesias, a dysarthtia. At long action of strong cold there can come the perversion of reactions of thermoreceptors and arise false sensation of heat. Ability to independent movement is lost, the tone of skeletal muscles quite often increases. Pupils are expanded or periodically are narrowed and extend, the breath which is slowed down (to 8 — 10 in 1 min.), superficial, sometimes with groans, an infrequent pulse (from 50 to 30 blows in 1 min.), is sometimes arrhythmic, is lowered by the ABP. The incontience of urine and a calla is possible. Temperature in a rectum 29 — 25 °.

In a coma stage consciousness is lost. Victims can have involuntary movements by the head and extremities, a priot-kryvaniye of eyes, a lockjaw, a muscle tension of a stomach, convulsive tonic contractions of muscles of extremities, preferential sgibately. Sometimes there is a motive excitement. Pupils are narrowed, their reaction to light sluggish or is absent, the lid reflex weak or is lost, there can be «swimming» of eyeglobes. Breath is superficial, rare (to 3 — 4 in 1 min.), sometimes like Cheyn — Stokes (see. Cheyna — Stokes breath ). Pulse is defined only on large arteries, rare (to 20 blows in 1 min.), is lowered by the ABP. Cardiac sounds are deaf, are listened hardly. Temperature in a rectum lower than 25 °.

Complications at O. lakes are substantially caused by falloff immunol, reactivity of an organism. In this regard in the subsequent development of inflammatory diseases — pneumonia is possible, pleurisy, acute respiratory diseases, etc. Besides, functions of other bodies and systems in this connection quite often arise astenisation, psychoses, trophic disturbances can be broken.

Diagnosis coolings of an organism establish on the basis of the anamnesis and data of inspection of the victim, among to-rykh major importance has determination of rectal temperature. The electric or mercury thermometer with graduation in the range of 15 — 45 ° is for this purpose necessary (see. Thermometry ).

Treatment

the Nature of medical aid at O. of the lake depends on depth of a hypothermia and the nature of disorders of life activity of an organism. In a compensatory stage of O. of the lake victims need only cancellation of a cold factor (the shelter from wind, additional clothes, etc.). In an adynamic stage under the corresponding conditions (stay in the warm room, warm drink, use of hot-water bottles, a heat bath) body temperature can also independently be normalized.

Victims in soporous and coma stages of O. of the lake need acute management. The main efforts focus on maintenance at them of breath and blood circulation, the prevention of further cooling and warming of an organism. Injured immediately transfer to the warm room, take off from it the got wet clothes, wrap up in blankets, lay over hot-water bottles. Eliminate retraction of language, suck away slime from a mouth, enter an air duct, make inhalation of oxygen, auxiliary or artificial ventilation of the lungs by the elementary methods (a mouth in a mouth, a mouth in Nov, through a respiratory tube, a mask) or by means of devices. In case of an apnoea and cordial activity carry out all complex of resuscitation actions (see. Resuscitation ). At a meneniye of cordial and respiratory analeptics inefficiently. At emergence of fibrillation of ventricles of heart the electrodefibrillation at body temperature lower than 29 ° is often also inefficient.

The main action for removal of the victim from a critical state is active warming. It needs to be begun as soon as possible. Warming in a bathtub with water t ° to 37 ° is the most effective. At the same time it is necessary to avoid warming of the head because of danger of deepening of a hypoxia of a brain owing to strengthening of a metabolism in the conditions of limited delivery of oxygen. It is possible to warm also blowing by warm air, an obkladyvaniye hot-water bottles, by means of electroblankets, light lamps, a gastric lavage warm water, inhalations of the warmed-up moistened air and oxygen. Active warming is stopped at a temperature in a rectum 33 — 34 ° in order to avoid development in the subsequent hyper thermal syndrome (see). At soporous and coma stages of O. of the lake it is reasonable to carry out warming in the conditions of a superficial anesthesia, full muscle relaxation and artificial ventilation of the lungs. It allows to eliminate nek-ry defense reactions of an organism on cold, in particular muscle tension and a shiver, to reduce oxygen requirement and to reduce the phenomena of a fabric hypoxia. During warming kapelno pour in the solution of glucose which is warmed up 5%, the balanced electrolytic solutions, Polyglucinum or reopoliglyukin. For replenishment of power material periodically enter on 40 — 50 ml 40% of solution of glucose with insulin and ascorbic to - that. Blood is transfused, as a rule, if there was blood loss. During the warming emergence or deepening of the arterial hypotension caused by expansion of peripheral vessels and receipt in a circulatory bed patol of metabolites from fabrics is possible with it is long the broken blood circulation. In such cases it is necessary to increase considerably the volume of infusions, being guided by the level of the central venous pressure and having provided hourly control of a diuresis. For improvement of cerebral circulation it is possible to use an Euphyllinum, neuroleptics or ganglioblokator in the doses which are not causing decrease in the ABP. For correction of acidosis pour in 100 — 200 ml of 5% of solution of hydrosodium carbonate. Use also the antihistamines reducing permeability of vascular walls. Aggravation patol, symptoms during the warming is expressed slightly less if originally along with outside internal ways of warming were applied (through a stomach, a rectum, lungs).

According to B. G. Volynsky and soavt. (1965), in soporous and coma stages of a hypothermia perhaps paradoxical effect of medicines therefore it is necessary to apply them strictly according to indications. For prevention and treatment of post-hypoxemic hypostasis of a brain and stimulation of a mocheotdeleniye in the course of warming and after it use diuretics (furosemide — 40 — 60 mg, a mannitol — 1 g/kg). Along with removal of the victim from a condition of a hypothermia perform prevention of possible complications or treatment of already arisen complications and associated diseases.

Prevention of cooling

Prevention of cooling includes a complex a dignity. - a gigabyte. actions: supply with warm clothes and footwear, the correct organization of work in cold season, the device of heating points, providing with hot meals, control of participants of marches and winter sports competitions, prohibition of alcohol intake before long stay on cold. Besides, the hardening of an organism and acclimatization of the person to severe conditions of the environment are of great importance (see. Acclimatization , Hardening ).

Cooling of an organism in the medicolegal relation

At survey of a corpse on site its detection pay attention to a characteristic pose of the feeling chilly person. If the person before death was in a condition of strong alcoholic intoxication, such pose often does not happen. One of proofs of intravital action of low temperature are traces of influence of heat of a body of the person on snow — a podtaivaniye and a freezing of snow in close proximity to a corpse or under it. Lack of this sign can indicate that the corpse was moved. Usually about a mouth and openings of a nose icicles, and on eyelashes — hoarfrost are found. Less often the so-called goosellesh as a result of reduction of the muscles raising hair of integuments can be observed; livors mortis — red or red-pink color that is explained by oversaturation of blood oxygen. Freezing injuries of separate body parts of I and II degrees are sometimes possible.

If death from cooling comes at a temperature below 0 °, then the corpse begins to freeze. At a freezing of substance of a brain there can be a cracking of bones of a skull or discrepancy of seams to a posthumous rupture of skin. Such picture can be mistakenly taken for a craniocereberal injury. Thawing of the frozen corpses should be made slowly at the room temperature; at the same time there comes hemolysis with the subsequent imbibition of bodies and fabrics. Microscopic examination of the frozen bodies and fabrics reveals in them cracks and cavities, education to-rykh is connected with mechanical effect of ice.

At an internal research of a corpse the sharp plethora of internals, hypostasis of a brain, its covers easy is noted. In a surface layer of a mucous membrane of a stomach hemorrhages in the form of multiple spots roundish or linearly - a twisting form the size from dot to 0,5 X 0,5 cm, dark brown or brown and reddish are found (Vishnevsky's spots). These hemorrhages are considered as a characteristic sign of death from a systemic effect of cold. They are formed in 75 — 90% of cases of death of cooling. Spotting of Vishnevsky is connected with the fact that as a result of action of low temperature on c. the N of page is broken regulation of trophic activity of century of N of page, in particular an abdominal brain. It leads to a vasospasm of a mucous membrane of a stomach, a necrosis of the respective site with the subsequent its digestion, to increase in permeability of walls of vessels and diapedetic hemorrhage. Color of these hemorrhages is caused by change of blood under the influence of salt to - you a gastric juice and formation of muriatic hematin.

At microscopic examination multiple small focal necroses in various bodies are found (in a mucous membrane of a stomach, renal tubules, etc.). In vessels of internals leukocytic staza, in a soft meninx and in substance of a brain — leukocytic perivascular infiltrates are observed. From the general cooling refer to signs of death also overflow by liquid blood and its blood clots of the left half of heart, aorta and arteries, scarlet color of tissue of lungs on a section. An important diagnostic character of death from cooling is disappearance of a glycogen, and also RNA from cells of a brain, liver, myocardium, skeletal muscles, a pancreas.

Court. - medical survey of the living persons treated to action cold weather in expert practice meets rather seldom and is carried out according to the practical standard (see. Survey ). Severity of injuries at O. of the lake is established according to «Rules of medicolegal definition of severity of injuries» (1978).



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V. I. Sidorenko; P. P. Shirinsky.

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