hypothermia

1. Pathol an abnormally low body temperature, as induced in the elderly by exposure to cold weather 2. Med the intentional reduction of normal body temperature, as by ice packs, to reduce the patient's metabolic rate: performed esp in heart and brain surgery

Hypothermia

A condition in which the internal temperature of the (human) body is at least 3.6^°F (2.0^°C) below an internal temperature of 98.6^°F (37^°C). Hypothermia represents a continuum of effects that vary with the severity of cold on physiological systems. The human body needs a specific internal temperature that is regulated on a minute-by-minute basis to maintain all normal body functions. The many physiological and behavioral processes involved in maintaining the internal temperature constant are called thermoregulation. See Thermoregulation

Various environmental situations predispose humans to hypothermia, which can occur even in the absence of cold. In fact, hypothermia is more common in temperate regions than in the colder climates. Because of the uniqueness of the situations in which hypothermia can occur, various kinds of hypothermia have been classified, all of which can prove fatal.

Primary hypothermia

Primary hypothermia is a decrease in internal temperature that is caused by environmental factors in which the body's physiological processes are normal but thermoregulation capability is overwhelmed by environmental stress.

Air (formerly exposure) hypothermia is thought to be the most common form. A person exposed to cold air experiences the same processes as a person in cold water, but air hypothermia occurs more slowly. The induction of air hypothermia is more subtle and therefore more dangerous since it can occur over a number of weeks. The degree to which a person reacts to a cold air stress is dependent on such factors as age, physical stamina, the intensity of the cold stress, and the responsiveness of the thermoregulatory system. One of the most convenient ways to determine whether someone is suffering from hypothermia is a noted change in personality: Complaints of fatigue, sluggish speech, and confusion are common, and in some cases the behavior resembles that of intoxication.

Initially, skin temperature falls rapidly, blood vessels to the skin constrict, and shivering begins. After 5–10 min, shivering ceases for about 10–15 min, but this is followed by uncontrollable shivering. In a cold situation, the nervous system causes blood to be redistributed away from the skin as the blood vessels of the skin close down to minimize heat transfer to the cold environment. The decrease in skin temperature coupled with vasoconstriction makes the person feel cold, and sometimes the fingers and toes can become painful. Internally, there is an increase in the levels of hormones that control metabolism, and blood is shunted primarily to the lungs, heart, and brain. The person becomes dehydrated as the inspired air is warmed and humidified. If the tense and shivering muscles do not generate enough heat, the hypothermic process begins and progresses for at least 3–5 h. As hypothermia continues, the arms become rigid, and the person loses the ability to make fine movements. During this period of time the heart rate initially increases, then stabilizes and as the person's internal temperature becomes progressively colder, the heart rate and respiration slow. In severely hypothermic persons, it is very difficult to detect a slow heart rate or determine if the person is breathing. A temperature of 95^°F (35^°C) is only the beginning of mild hypothermia and shivering can continue for hours, depending on the muscle and fat supplies available. Eventually, the environment becomes overwhelming. At 86^°F (30^°C), the person loses consciousness and shivering ceases. Death does not occur until the internal temperature drops further: Death results at 68–77^°F (20–35^°C) because of cardiac standstill.

When a person falls into cold water, a gasping response is triggered by the thermal receptors on the skin. For some individuals, the cold stress may trigger a heart attack. Although as much of the body as possible should be kept out of the water, many victims of immersion hypothermia stay in the cold water because they cannot tell how cold they are. Shivering becomes generalized and, unlike its effect in cold air, may cause a faster drop in internal temperature since the water layer closest to the body is stirred and convective heat loss is promoted. Although the greater conductive property of water relative to air is a major heat sink, physiological and behavioral responses act to minimize the heat loss. Survival in 50^°F (10^°C) water is possible for several hours at most if the person is dressed in street clothes and a life jacket.

The cooling of the body in submersion hypothermia allows the brain and heart to withstand approximately 45 min of oxygen debt. This is most operative for young children. A child can survive for an extended period of time while completely submerged because the body is undergoing both internal and external cooling. As the child is drowning, cold water is swallowed and enters the lungs, which cools the core. At the same time, the cold water that bathes the skin rapidly cools the periphery. The multiple effects of the internal and external cooling decrease the metabolic rate and give the child a window of safety of approximately 45 min. In warm water, survival is possible for only 5–7 min.

Secondary hypothermia

A decrease in core temperature caused by an underlying pathology that prevents the body from generating enough core heat is referred to as secondary hypothermia. If any of the thermoregulatory systems are altered, the body's ability to generate heat decreases and hypothermia can then develop without warning. Insufficient muscle mass to generate heat, medications that interfere with metabolism, an underlying systemic infection, decreased thyroid hormone production, and paralysis predispose to hypothermia. Premature infants with low body fat and a large surface-to-volume ratio lose heat rapidly and are at risk for becoming hypothermic. The elderly are perhaps the most susceptible to secondary hypothermia. However, whether the process of aging with no associated debility also alters the thermoregulatory system in the elderly remains to be determined.

Clinical hypothermia

Some cardiac surgical procedures require clinically induced cooling to stop the heart from beating. Induced hypothermia lowers the oxygen demand of the body tissues, so that oxygenated blood need not circulate. In the case of coronary bypass surgery, the entire body is cooled, enabling the surgeons to work for an extended period of time on the cold heart.

Frostbite

In hypothermia, the body's internal temperature decreases, but no solid freezing takes place. In frostbite, which is freezing of the digits or the limbs, there is actual formation of ice crystals. Basically the digits go through various stages of cooling. Initially, in the prefreeze phase, the finger temperature is 37.4–50^°F (3–10^°C). Next, at 24.8^°F (-4^°C) ice crystals form outside the cells of the digits, circulation is limited, and cell death takes place if the process is allowed to continue. The cells of the digits and limbs can tolerate low temperatures that would be lethal to brain or nerve cells. However, once they are rewarmed and thawed, they develop an increased sensitivity to the cold and become more susceptible to frostbite. Any part of the body can become frostbitten, but the fingers, toes, ears, nose, and cheeks are most often affected. See Homeostasis

Hypothermia

a decrease in body temperature in warm-blooded animals and humans, as a result of heat emission that exceeds the formation of heat in the body. At low environmental temperatures animals and humans are protected against hypothermia by heat insulation (the fat layer, fur, plumage, or clothing). When the heat insulation is insufficient, a physiological reaction to chilling results, involving limitation of heat emission from the skin as a result of blood flow away from the skin to the internal organs, sharp increase in metabolism, increased heat production in the muscles due to movements, work, and muscular trembling. In the cold, hypothermia in humans may develop only after exhaustion of these physiological mechanisms. It may also develop if the individual falls asleep from fatigue or is completely motionless, and it arises readily when there is a disturbance in thermoregulation (drunkenness, shock, narcotic sleep, and blood loss). In cold water, heat emission increases to an enormous degree, and increased heat production cannot compensate for it. At water temperatures of 0°-4° C death from hypothermia may result within 40-60 minutes. Lowering the body temperature to 33°-32° C induces drowsiness and dulled consciousness. Under 30° C there is a progressive decrease in metabolism and blood pressure and a slowing of heartbeat and respiration. At 27°-26° C there is loss of consciousness, and at around 23°-20° C respiration and then heartbeat cease. Physiological hypothermia is observed in some animals during winter hibernation as an adaptive reaction that makes it possible for them to get along for months without food with a small loss of weight. Chilled tissues (for example, of the brain and heart), whose metabolism is sharply decreased by hypothermia, tolerate oxygen deficiency more readily and survive cessation of blood circulation for a longer period. The use of artificial hypothermia in contemporary surgery is based on these facts.

P. N. VESELKIN

Artificial hypothermia The generalized chilling of a warmblooded organism, accomplished for prophylactic and therapeutic purposes on the basis of inhibition of the mechanisms of thermoregulation, is artificial hypothermia. The first investigations of the effect of cold on the human body and possibilities for the medical use of hypothermia are associated with the name of the English surgeon D. L. Carry (1798). Further study of hypothermia was conducted in the 19th and early 20th centuries on animals. In 1940 the American scientists L. Smith and T. Fay attempted to treat cancer by inducing hypothermia for five to eight days. The attempt was not successful, but it demonstrated the possibility of maintaining vital functions of the human body under general hypothermia at 28°-30° C and under narcosis. Broad application of hypothermia in clinical practice began after 1950, when the Canadian scientist W. Bigelow showed in animal experiments the possibility of safely disconnecting the heart and stopping blood circulation for ten to 15 minutes at temperatures of 26°-28° C. In 1952 the American physicians F. Levy and M. Taufic performed the first operation in the world on an open “dry” heart (that is, a heart disconnected from blood circulation) under conditions of moderate hypothermia, and a few years later heart operations under hypothermia became firmly established in everyday practice. The principal effect of hypothermia is conditioned by the decrease in intensity of metabolic processes under the action of cold and the decrease in the organs’ and tissues’ requirements for oxygen associated with this.

When the mechanisms of thermoregulation are blocked, the oxygen requirement of the body decreases. It has been established that at temperatures of 26°-27° C the general oxygen requirement decreases by 40 percent, the oxygen requirement of the cardiac muscles decreases by 50 percent, and the oxygen requirement of the brain decreases by 33 percent.

Hypothermia can be achieved by immersing the patient in a cold-water bath, wrapping the body in ice bags, using special blankets in which cold water circulates, or placing the patient in a special installation into which cold air is forced. Also used are various methods of chilling the blood outside the body by means of heat exchangers—extracorporeal refrigeration. Craniocerebral hypothermia, which involves chilling the head, is beginning to be widely used. It is most effective in reviving the body or in extremely grave (terminal) conditions.

However, hypothermia is a pathological condition for a warm-blooded organism. Under the influence of hypothermia the functioning of the heart changes, and its irritability increases. Transient disturbances are observed in the functions of the kidneys and liver and in vascular tone. The best means of preventing reciprocal reaction of the body to hypothermia is shallow narcosis with complete relaxation of the muscles induced by curare-like drugs and inhibition of the neuroendocrine system by a complex of pharmacological preparations.

In heart operations hypothermia at temperatures of 29°-30° C is most advisable, because chilling to lower temperatures involves the danger of disrupting heart operation (fibrillation). The permissible period for disconnecting the heart at this temperature is no more than ten minutes.

Hypothermia may be used over a period of many days for therapeutic purposes in cases of the aftereffects of hypoxia, serious craniocerebral trauma, and pronounced hyperthermia. The therapeutic effect of hypothermia depends greatly on its timely, early use.

REFERENCE

Burton, A., and O. Edholm. Chelovek v usloviiakh kholoda. Moscow, 1957. (Translated from English).
Petrov, I. R., and E. V. Gubler. Iskusstvennaia gipotermiia. Leningrad, 1961.
Petrovskii, B. V., G. M. Solov’ev, and A. A. Buniatian. Gipoter-micheskaia perfuziia v khirurgii otkrytogo serdtsa. Yerevan, 1967.
Darbinian, T. M. Sovremennyi narkoz i gipotermiia v khirurgii vrozhdennykh porokov serdtsa. Moscow, 1964.
Cooper, K., and D. Ross. Hypothermia in Surgical Practice. London, 1960.

A. A. BUNIATIAN

hypothermia

[‚hī·pō′thər·mē·ə] (physiology) Condition of reduced body temperature in homeotherms.

hypothermia

Hypothermia

Definition

Hypothermia, a potentially fatal condition, occurs when body temperature falls below 95°F (35°C).

Description

Although hypothermia is an obvious danger for people living in cold climates, many cases have occurred when the air temperature is well above the freezing mark. Elderly people, for instance, have succumbed to hypothermia after prolonged exposure to indoor air temperatures of 50-65°F (10-18.3°C). In the United States, hypothermia is primarily an urban phenomenon associated with alcoholism, drug addiction, mental illness, and cold—water immersion accidents. The victims are often homeless male alcoholics. Officially, 11,817 deaths were attributed to hypothermia in the United States from 1979 to 1994, but experts suspect that many fatal cases go unrecognized. Nearly half the victims were 65 or older, with males dominating every age group. Nonwhites were also overrepresented in the statistics. Among males 65 and older, nonwhites outnumbered whites by more than four to one.

Causes and symptoms

Measured orally, a healthy person's body temperature can fluctuate between 97°F (36.1°C) and 100°F (37.8°C). Survival depends on maintaining temperature stability within this range by balancing the heat produced by metabolism with the heat lost to the environment through (for the most part) the skin and lungs. When environmental or other changes cause heat loss to outpace heat production, the brain triggers physiological and behavioral responses to restore the balance. The involuntary muscular activity of shivering, for example, aids heat production by accelerating metabolism. But if the cold stress is too great and the body's defenses are overwhelmed, body temperature begins to fall. Hypothermia is considered to begin once body temperature reaches 95°F (35°C), though even smaller drops in temperature can have an adverse effect.Hypothermia is divided into two types: primary and secondary. Primary hypothermia occurs when the body's heat-balancing mechanisms are working properly but are subjected to extreme cold, whereas secondary hypothermia affects people whose heat-balancing mechanisms are impaired in some way and cannot respond adequately to moderate or perhaps even mild cold. Primary hypothermia typically involves exposure to cold air or immersion in cold water. The cold air variety usually takes at least several hours to develop, but immersion hypothermia will occur within about an hour of entering the water, since water draws heat away from the body much faster than air does. In secondary hypothermia, the body's heat-balancing mechanisms can fail for any number of reasons, including strokes, diabetes, malnutrition, bacterial infection, thyroid disease, spinal cord injuries (which prevent the brain from receiving crucial temperature-related information from other parts of the body), and the use of medications and other substances that affect the brain or spinal cord. Alcohol is one such substance. In smaller amounts it can put people at risk by interfering with their ability to recognize and avoid cold-weather dangers. In larger amounts it shuts down the body's heat-balancing mechanisms.Secondary hypothermia is often a threat to the elderly, who may be on medications or suffering from illnesses that affect their ability to conserve heat. Malnutrition and immobility can also put the elderly at risk. Some medical research suggests as well that shivering and blood vessel narrowing—two of the body's defenses against cold—may not be triggered as quickly in older people. For these and other reasons, the elderly can, over a period of days or even weeks, fall victim to hypothermia in poorly insulated homes or other surroundings that family, friends, and caregivers may not recognize as life threatening. Another risk for the elderly is the fact that hypothermia can easily be misdiagnosed as a stroke or some other common illness of old age.The signs and symptoms of hypothermia follow a typical course, though the body temperatures at which they occur vary from person to person depending on age, health, and other factors. The impact of hypothermia on the nervous system often becomes apparent quite early. Coordination, for instance, may begin to suffer as soon as body temperature reaches 95°F (35°C). The early signs of hypothermia also include cold and pale skin and intense shivering; the latter stops between 90°F (32.2°C) and 86°F (30°C). As body temperature continues to fall, speech becomes slurred, the muscles go rigid, and the victim becomes disoriented and experiences eyesight problems. Other harmful consequences include dehydration as well as liver and kidney failure. Heart rate, respiratory rate, and blood pressure rise during the first stages of hypothermia, but fall once the 90°F (32.2°C) mark is passed. Below 86°F (30°C) most victims are comatose, and below 82°F (27.8°C) the heart's rhythm becomes dangerously disordered. Yet even at very low body temperatures, people can survive for several hours and be successfully revived, though they may appear to be dead.

Diagnosis

Information on the patient's prior health and activities often helps doctors establish a correct diagnosis and treatment plan. Pulse, blood pressure, temperature, and respiration require immediate monitoring. Because the temperature of the mouth is not an accurate guide to the body's core temperature, readings are taken at one or two other sites, usually the ear, rectum, or esophagus. Other diagnostic tools include electrocardiography, which is used to evaluate heart rhythm, and blood and urine tests, which provide several kinds of key information; a chest x ray is also required. A computed tomography scan (CT scan) or magnetic resonance imaging (MRI) may be needed to check for head and other injuries.

Treatment

Emergency medical help should be summoned whenever a person appears hypothermic. The danger signs include intense shivering; stiffness and numbness in the arms and legs; stumbling and clumsiness; sleepiness, confusion, disorientation, amnesia, and irrational behavior; and difficulty speaking. Until emergency help arrives, a victim of outdoor hypothermia should be brought to shelter and warmed by removing wet clothing and footwear, drying the skin, and wrapping him or her in warm blankets or a sleeping bag. Gentle handling is necessary when moving the victim to avoid disturbing the heart. Rubbing the skin or giving the victim alcohol can be harmful, though warm drinks such as clear soup and tea are recommended for those who can swallow. Anyone who aids a victim of hypothermia should also look for signs of frostbite and be aware that attempting to rewarm a frostbitten area of the body before emergency help arrives can be extremely dangerous. For this reason, frostbitten areas must be kept away from heat sources such as campfires and car heaters.Rewarming is the essence of hospital treatment for hypothermia. How rewarming proceeds depends on the body temperature. Different approaches are used for patients who are mildly hypothermic (the patient's body temperature is 90-95 °F [32.2-35 °C]), moderately hypothermic (86-90 °F [30-32.2 °C]), or severely hypothermic (less than 86 °F [30 °C]). Other considerations, such as the patient's age or the condition of the heart, can also influence treatment choices.Mild hypothermia is reversed with passive rewarming. This technique relies on the patient's own metabolism to rewarm the body. Once wet clothing is removed and the skin is dried, the patient is covered with blankets and placed in a warm room. The goal is to raise the patient's temperature by 0.5-2 °C an hour.Moderate hypothermia is often treated first with active external rewarming and then with passive rewarming. Active external rewarming involves applying heat to the skin, for instance by placing the patient in a warm bath or wrapping the patient in electric heating blankets.Severe hypothermia requires active internal rewarming, which is recommended for some cases of moderate hypothermia as well. There are several types of active internal rewarming. Cardiopulmonary bypass, in which the patient's blood is circulated through a rewarming device and then returned to the body, is considered the best, and can raise body temperature by 1-2 °C every 3-5 minutes. However, many hospitals are not equipped to offer this treatment. The alternative is to introduce warm oxygen or fluids into the body.Hypothermia treatment can also include, among other things, insulin, antibiotics, and fluid replacement therapy. When the heart has stopped, both cardiopulmonary resuscitation (CPR) and rewarming are necessary. Once a patient's condition has stabilized, he or she may need treatment for an underlying problem such as alcoholism or thyroid disease.

Prognosis

Victims of mild or moderate hypothermia usually enjoy a complete recovery. In regard to severely hypothermic patients, the prognosis for survival varies due to differences in people's physiological responses to cold.

Key terms

Antibiotics — Substances used against microorganisms that cause infection.Computed tomography — A process that uses x rays to create three-dimensional images of structures inside the body.Esophagus — A muscular tube through which food and liquids pass on their way to the stomach.Insulin — A substance that regulates blood glucose levels. Glucose is a sugar.Magnetic resonance imaging — The use of electromagnetic energy to create images of structures inside the body.Metabolism — The chemical changes by which the body breaks down food and other substances and builds new substances necessary for life.Nervous system — The system that transmits information, in the form of electrochemical impulses, throughout the body. It comprises the brain, spinal cord, and nerves.Rectum — The lower section of the large intestine. The intestines are part of the digestive system.Stroke — A condition involving loss of blood flow to the brain.Thyroid — A gland (fluid-secreting structure) in the neck. It plays an important role in metabolism.

Prevention

People who spend time outdoors in cold weather can reduce heat loss by wearing their clothing loosely and in layers and by keeping their hands, feet, and head well covered (30-50% of body heat is lost through the head). Because water draws heat away from the body so easily, staying dry is important, and wet clothing and footwear should be replaced as quickly as possible. Wind- and water-resistant outer garments are also crucial. Alcohol should be avoided because it promotes heat loss by expanding the blood vessels that carry body heat to the skin.Preventing hypothermia among the elderly requires vigilance on the part of family, friends, and caregivers. An elderly person's home should be properly insulated and heated, with living areas kept at a temperature of 70 °F (21.1 °C). Warm clothing and bedding are essential, as are adequate food, rest, and exercise; warming the bed and bedroom before going to sleep is also recommended. Older people who live alone should be visited regularly—at least once a day during very cold weather—to ensure that their health remains sound and that they are taking good care of themselves. For help and advice, family members and others can turn to government and social service agencies. Meals on wheels and visiting nurse programs, for instance, may be available, and it may be possible to obtain financial aid for winterizing and heating homes.

Resources

Books

Petty, Kevin J. "Hypothermia." In Harrison's Principles of Internal Medicine, edited by Anthony S. Fauci, et al. New York: McGraw-Hill, 1997.

hypothermia

[hi″po-ther´me-ah] low body temperature; it may be symptomatic of a disease or disorder of the temperature-regulating mechanism of the body, may be due to exposure to cold, or may be induced for certain surgical procedures or as a therapeutic measure. Hypothermia is a nursing diagnosis accepted by the North American Nursing Diagnosis Association, defined as body temperature reduced below the normal range for an individual but not below 35.6°C rectally (36.4°C rectally for the newborn). adj., adj hypother´mal, hypother´�mic.
Emergency treatment for hypothermia includes administration of warm intravenous fluid and use of esophageal rewarming tubes and special rewarming blankets. Resuscitation efforts such as cardiopulmonary resuscitation should continue until the patient is warmed to a normal core temperature; if there is no other change, the patient may be pronounced dead.accidental hypothermia unintended lowering of body heat due to prolonged exposure to cold. Hypothermia is a chilling of the entire body, but the extremities can withstand temperatures as much as 10 to 15°C (20 to 30°F) lower than the torso, where vital organs are located. When the core temperature drops even a few degrees, physiologic changes can lead to fatal cardiac arrhythmias and respiratory failure. Persons most at risk for accidental hypothermia include the very young, the very thin, the very old, the mentally challenged or emotionally unstable, alcohol and drug abusers, and the homeless. Symptoms range from mild shivering and complaints of feeling chilled to loss of consciousness, absence of reflexes, and barely detectable pulse and respirations.Prevention and Treatment. Accidental hypothermia can be avoided by eating high-energy foods, exercising when in the cold, wearing layers of clothing, and covering the head. From one half to two thirds of the body heat is lost through the head. For persons on a fixed or limited income, suggestions for avoiding hypothermia in a cold home must be realistic. Blankets and quilted covers that snap together to form a snug bag are alternatives to turning up the thermostat. A loose knitted cap worn day and night can help reduce loss of body heat. Persons who live alone may need help in finding another individual or agency that can check on them daily when the outside temperatures are very low.
The diagnosis of hypothermia may be missed if a clinical thermometer such as the kind used to measure fever is employed to determine the core temperature of a potential hypothermia victim. These thermometers rarely register temperatures below 34.5°C (94.1°F), while the patient's actual temperature can be as low as 30°C (86°F). Emergency departments should be equipped with special monitoring equipment that gives a true picture of the body temperature.
Once hypothermia is diagnosed, rewarming is indicated. Outside a medical facility the rewarming should be gradual so as to avoid respiratory and cardiac problems associated with rapidly sending cold blood back to the heart. The torso is warmed first by wrapping it in warm blankets or submersion in a tepid bath. Once the core temperature reaches 35°C (95°F), the extremities are warmed.environmental hypothermia accidental hypothermia due to heat loss due to a combination of convection, conduction, and radiation to the surrounding ambient air.induced hypothermia deliberate reduction of the temperature of all or part of the body; sometimes used as an adjunct to anesthesia in surgical procedures involving a limb, and as a protective measure in cardiac and neurologic surgery. The hypothermia may be continued only for the duration of the operation or it may be prolonged for as long as 5 days, depending on the reason for its use. See also treatment" >hypothermia treatment.Local Hypothermia. This is a type of anesthesia" >refrigeration anesthesia restricted to a part of the body, such as a limb. It usually is used to produce surgical anesthesia immediately before amputation. Advantages include minimal risk of shock, lowering of cell metabolism, and elimination of the need for inhalation anesthesia in patients who are poor surgical risks. The part to be anesthetized is packed in ice or wrapped in a special refrigeration unit consisting of coiled tubes. Tourniquets are applied to the limb to inhibit circulation and avoid general chilling of the patient. The limb is chilled for 3 to 5 hours before amputation.General Hypothermia. Generalized lowering of the body temperature decreases the metabolism of tissues and thereby the need for oxygen; it is used in various surgical procedures, especially on the heart. The core temperature is maintained between 26°C and 32°C (78.8°F and 89.6°F).
To induce general hypothermia, the patient is wrapped in a cooling blanket containing coils through which cold water or an antifreeze, or both, are circulated. The fastest method for achieving hypothermia is extracorporeal cooling of the blood; the patient's blood is removed through a cannula inserted in a large vessel, circulated through refrigerated coils and returned via another cannulated vessel.
Rewarming of the patient is accomplished simply by removing cooling blankets and allowing the temperature to rise gradually and naturally. In most cases regular blankets are used to maintain body warmth. External heat in the form of hot water bottles or warm tub baths, if used at all, must be applied with extreme caution to avoid burning the patient.Patient Care. During hypothermia and the rewarming process the patient's temperature, pulse, respiration, and blood pressure must be checked frequently. Special electronic thermometers are often used so that the body temperature can be monitored at all times. In prolonged hypothermia, cardiac irregularities or respiratory difficulties may develop quickly; the patient must be watched constantly for changes in the vital signs, and any changes must be reported immediately. The skin also should be observed for signs of developing pressure ulcers, edema, or marked discoloration.
The patient should be turned at least every 2 hours, with special attention to proper positioning and good body alignment. Decreased secretion of saliva and mouth-breathing demand frequent mouth care. The eyes may need to be irrigated frequently and covered with compresses moistened with physiologic saline solution or artificial tears if the corneal reflex is diminished and eye secretions are reduced.
Intake and output are measured and recorded. An indwelling catheter is inserted prior to induction of hypothermia and is left in place until normal body temperature is established. This is necessary because urinary output is diminished during hypothermia. Fluids are given intravenously and the oral intake of food and liquids is prohibited because of depression of the gag reflex.
Shivering during prolonged hypothermia must be avoided as it tends to elevate the body temperature and increase metabolic needs, thereby defeating the purpose of hypothermia.
During the rewarming process the patient must be observed for signs of increased tendency to bleed and of gastric distention; these are common complications. After the body temperature returns to normal and becomes stabilized, the patient is allowed to progress to a normal diet and physical activities.moderate hypothermia body temperature of 23° to 32°C, resulting from surface cooling.profound hypothermia body temperature of 12° to 20°C.regional hypothermia temperature reduction in a limb or organ resulting from application of external cold or perfusion with a cold solution.symptomatic hypothermia pathologic reduction of body temperature as a result of decreased heat production or increased heat loss. Hypothyroidism, severe blood loss with circulatory failure, and damage to the heat-producing cells of the hypothalamus can lead to decreased heat production. Prolonged exposure to cold, overdosage of antipyretic drugs, such as aspirin, and profuse sweating (diaphoresis) are some causes of increased heat loss and resultant hypothermia.

hy·po·ther·mi·a

(hī'pō-ther'mē-ă), A body temperature significantly less than 98.6°F (37°C). [hypo- + G. thermē, heat]

hypothermia

(hī′pə-thûr′mē-ə)n. Abnormally low body temperature.

hy′po·ther′mic (-mĭk) adj.

hypothermia

Critical care A ↓ in core/rectal body temperature ≤ 35ºC–95ºF, due to long-term occupational or recreational exposure to ↓ air or water temperatures Epidemiology Hypothermia causes 750 deaths/yr; racial differences in mortality 3.2–white vs 13.1–blacks deaths/106 ♂; 1.4 vs 4.1 deaths/106–♀–US Clinical ↓ Respiratory rate, metabolic acidosis, ↓ pulse, ↓ blood pressure, ventricular fibrillation, hypo- or hyperglycemia, coagulopathy, hemoconcentration, pneumonia, renal failure, pancreatitis; when extreme and prolonged, drowsiness, delirium, coma, shivering, numbness, fatigue, poor coordination, slurred speech, impaired mentation, blue and/or puffy skin, irrational thinking Risk factors Extremes of age–related to ↓ shivering mechanisms, less protective fat, ↓ mobility, ↓ metabolic rate, and chronic illness, alcohol use/abuse, use of neuroleptic agents, hypothyroidism, mental illness, starvation, dehydration, poverty, immobilizing illness, and young adults in winter sports Treatment External rewarming, best performed in a warm tub at 40-42ºC–104-107.6ºF; internal rewarming is recommended for those with severe hypothemia and includes extracorporeal blood warming using a femorofemoral bypass and/or repeated peritoneal dialysis with 2 L of warmed–43ºC K+-free dialysate solution. See Accidental hypothermia Neurology The intentional cooling Pts with traumatic brain injury and 'salvageable' Glasgow coma scores–5 to 7 on admission to 33º for 24 hrs is associated with an improved survival–62% good outcomes in the hypothermia group vs 38% good outcomes in the normothermia group Mechanism Hypothermia ↓ 2º brain injury by an unknown mechanism, possibly by ↓ brain metabolism, ↓ extracellular concentrations of excitatory neurotransmitters–eg, glutamate, ↓ post-traumatic inflammatory response, with ↓cytokine release.

hy·po·ther·mi·a

(hī'pō-thĕr'mē-ă) A core body temperature significantly lower than 98.6°F (37°C). [hypo- + G. thermē, heat]

hypothermia

Below-normal body temperature. This may occur, especially in the elderly, as a result of prolonged exposure to low temperatures or may be brought about deliberately to reduce tissue oxygen requirements during surgery, especially HEART SURGERY.

hypothermia

an abnormally low body temperature that reduces the metabolic rate to a dangerous level and can lead to death, often occurring in elderly people subjected to cold weather. Hypothermia is sometimes induced in medical treatment in order to reduce metabolic activity.

hy·po·ther·mi·a

(hī'pō-thĕr'mē-ă) A body temperature significantly less than 98.6°F (37°C). [hypo- + G. thermē, heat]

Patient discussion about hypothermia

Q. what is the red line when your body temperature drops before you are getting hypothermia? A. Hypothermia is a condition in which an organism's temperature drops below that required for normal metabolism and function. For people in stage 1 hypethermia, body temperature drops by 1-2°C below normal temperature (35-36°C). Mild to strong shivering occurs. In stage 2, body temperature drops by 2-4°C (35-33 degrees). Shivering becomes more violent. Muscle mis-coordination becomes apparent and movements are slow and labored and there is mild confusuin. In stage 3, body temperature drops below approximately 32 °C (89.6 °F). Shivering usually stops and there's difficulty speaking, sluggish thinking, and amnesia start to appear. Cellular metabolic processes shut down. This is life threatening.

Q. what can be done for spontaneous hypothermia? is there a deficiency of hormones or anything that can be taken A. hypothermia can be caused by al sort of things. Some bacterial infections, poisoning, aciduria , hypothyroidism and more. Is this the only symptom? I’m sure there are some others. But I think this could be a good idea to check up with a Dr.

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hy·po·ther·mi·a

hypothermia

hypothermia

hypothermia

Hypothermia

Primary hypothermia

Secondary hypothermia

Clinical hypothermia

Frostbite

Hypothermia

REFERENCE

hypothermia

hypothermia

Hypothermia

Definition

Description

Causes and symptoms

Diagnosis

Treatment

Prognosis

Key terms

Prevention

Resources

Books

hypothermia

hy·po·ther·mi·a

hypothermia

hypothermia

hy·po·ther·mi·a

hypothermia

hypothermia

hy·po·ther·mi·a

Patient discussion about hypothermia

hypothermia

Antonyms for hypothermia

noun subnormal body temperature

Related Words

Antonyms