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31 Cards in this Set
- Front
- Back
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What is body temperature?
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Heat produced - heat lost = body temperature
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What is thermoregulation?
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The blance between heat lost and heat produced.
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How is thermoregulation maintained?
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It is maintained by neurological and cardiovascular mechanisms.
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What controls the body temperature?
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The hypothalamus, located between the cerebral hemispheres controls the body temperature.
The ANTERIOR hypothalamus controls heat LOSS and the POSTERIOR hypothalamus controls heat PRODUCTION. |
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Mechanisms of heat loss?
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Sweating, vasodilating (widening) of blood vessels and inhivition of heat production.The body redistributes blood to surface vessels to promote heat loss.
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Mechanismes of heat production?
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Vasoconstriction (narrowing) of blood vessels reduces blood flow to the skin and exteremeties, voluntary muscle contraction and muscle shivering.
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What can cause serious alterations in temperature control?
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Disease or trauma to the hypothalamus or to the spinal cord.
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How is heat produced y the body?
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Heat production is a by-product of metabolism, which is the chemical reaction in all body cells. Primary fuel source is food. Activities requing additional chemical reactions increase the metabolic rate. As metabolism increased, additional heat is produced. Heat production occurs during rest, coluntary movements, involuntary shivering and nonshivering thermogenesis.
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What is basal metabolic rate (BMI)?
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Heat produced by the body at absolute rest. Depends on the body surface area. Thyroid hormones affect hte BMR. By promoting the breakdown of body glucse and fat, thyroid hormones increase the rate of chemical reactions in almost all cells of the body.
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What causes BMI to change?
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1. Large amounts of thyroid hormones can ncrease BMR 100% above normal. Absence can cut the BMR in half, causing decrease in heat production.
2. Testosterone increases BMR; 3. Activities. 4. Shivering Nonshivering thermogenesis - in neonates, vascular brown tissue, present at birth, is metabolized for heat production. |
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How is heat lost?
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The skin's exposure to the environment result in constant, normal heat loss through radiation, conduction, convection, and evaporation.
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What is radiation?
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Transfer of heat from the surface of one object to the surface of another without direct contact between the two. Up to 85 % of the human body's surface area radiates heat to the environment.
Works through vasodilation or vasoconstriction. If the environment is warmer than the skin, the body absorbs heat through radiation - standing up exposes greater radiating surface area. Covering the body with dark, closely wooven clotig decreases radiation - lying in a fetal position. |
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What is conduction?
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The transfer of heat from one object to another with direct contact. Accounts for a small amount of heat loss.
Solids, liquids and gases conduct heat through contact -ice pack, cold bath. |
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What is convection?
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The tranfer of heat away by air movement.
Fan. Increases when moistened skin comes into contact with slightly moving air. |
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What is evaporation?
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The transfer of heat energy when liquid is changed to a gas.About 600 to 900 mL a day.
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What kind of factors affect body temperature?
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Age -
Exercise Hormone level Carcadian rhythm - chqanges 0.5 to 1 C during a 24-hour period. Lowest between 1 and 4 AM, at max at about 6 PM. Stress - increase Environment Temperature alterations - fever, hyperthermia, heatstroke, heat exhaustion, hypothermia. |
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How does the fever affect the body temperature?
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Fever of pyrexia occurs because heat-loss mechanisms are unable to keep pace with excess heat production, resulting in an abnormal rise in body temperature. Not harmful if it stays below 39 C (102.2 F).
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What happens in the body during a fever?
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Cellular metabolism increases and axygen consumption rises. The body's metabolism increases 10 for every degree Celcius of temperature elevation. Heart and respiratory rates increase - great stress with patients with cardiac or respiratory problems. Increased metabolism requires additional oxygen. If the body can't meat the demand, cellular hypoxia (inadequate O) occurs. Myocardial hypoxia causes angina, cerebral hypoxia produces confusion. Interventions include O theraphy and maintaining optimum fluid volume.
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What happens in the body during a hypeRthermia?
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An elevated body temperature related to the body's inability to promote heat loss.
Malignant hyperthermia is a hereditary condition of uncontrolled heat production, occurring when susceptible persons receive certain anesthetic drugs. |
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What happens in the body during a heatstroke?
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Prolonged exposure to the sun or high environmental temperatures depresses hypothalmic functions and overwhelms the body's heat-loss mechanisms.
Clients who are at risk are very young and old, those with cardiovascular disease, hypothyroidism, diabetes, or alcoholism, those who take medications that decrease the body's ability to lose heat - diuretics. Symptoms include confusion, delirium, excess thirst, nausea, muscle cramps. Most important sign of heatstroke is hot, dry skin. EMERGENCY SITIATION. IV fluids, irrigating the stomach and lower bowel with cool solutions and hypOthermia blankets. |
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What happens in the body during a heat exhaustion?
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Heat exhaustion occrs from excess water and electrolyte loss. Caused by environmental heat exposure, the client exhibits signs and symptoms of fluid volume deficit.
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What happens in the body during a hypOthermia?
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Heat loss during prolonged exposure to cold. It overwhelms the body's ability to produce heat. When skin temperature drops to 35 C (95 F), the client suffers uncontrolled shivering, loss of memory, depression, and poor judgment. As body temp. falls below 34.3 C ((4 F), heart rate, respiratory rate, and blood pressure fall. Client experiences cardiac dysrhythmias, loss of consciousness, and unresponsiveness to painful stimuli.
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What happens in the body during a frostbite?
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The body is exposed to subnormal temperatures nad ice crystals form inside the cell. Permanent circulatory and tissue damage occurs. The injured area becomes white, waxy and firm to the touch.
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How is tympanic temperature special?
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Tympanic temperature relies on the radiation of body heart to an infated sensor. Because the tympanic membrane shares the same arterial blood supply as the hypothalamus, the tympanic membrane is a core temperature.
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Delegation considerations
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Skill can be delegated. But the nurse is responsible for assessing changes in body temperature.
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Things to know about signs and symptoms that influence body temperature.
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1. When taking oral temperature, wait 20 to 30 minutes before measuring of client has smoked or ingested hot or cold liquids or foods.
2. When taking rectal temperature assist client to Sims' position with upper leg flexed. Insert 2.5 to 3.5 cm (1 to 1 and a half inches) into the anus for adult. 3. When taking tympanic temperature pull ear pinna backward, up and out for an adult. Children 3 and younger, pull the pinna down and back. 4. If temperature is abnormal or second reading is necessary, wait 2 to 3 minutes before repeating the measurement in the same ear. |
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Unexpected outcomes and related interventions.
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Temperature is 1 C above usual range - assess possible sites for localized infection and for related data suggesting a systemic infection.
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Recording temperature.
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Record temperature after administration. Report anbormal findings to nurse in charge or health care provider.
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About delegation.
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Temperature measurement can be delegated. It is therse's responsibility to assess the significance of the findings.
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Interventions to trat fever.
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1. Antipyretics - drugs that reduce fever - acetaminophen, salicylates, indomethacin and ketoralac - all nonsteroidal drugs, reduce fever by increasing heat lost.
2. Corticosteroids reduce heat production by interfering with the immune system and mask signs of infection. Not used to treat fever. They suppress fever in response to a pyrogen. 3. Sponge baths, bathing with alcohol water solutions, applying ice packs and cooling fans. |
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Nursing interventions for clients with a fever.
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1. Minimize heat production - reduce the frequency of activities that increase oxygen demand.
2. Satisfy requirements for increased metabolic rate: provide supplemental oxygen theraphy as ordered to improve oxygen delivery to body cells; offer well-balanced meals; provide fluids (at least 3 L/day for client with normal cardiac and renal function) to replace fluids lost through insensible water loss and sweating. 3. Control envoronmental temperature to 21 to 27 C (70 to 80 F). |
