Thermoregulation Flashcards
Definition of thermoregulation
The process of maintaining the core body temperature at a nearly constant state.
Normal body temperature ranges
36.2°C to 37.6°C, or an average of 37°C. Fluctuation outside this range is an indication of a disease process, strenuous, or unusual activity, or extreme environmental exposure.
(97°F to 100°F with an average of 98.6°F.)
Definition of normothermia
Normal body temperature. Ranges between 36.5°C and 37.2°C.
Definition of hypothermia
Body temperature below 36.2°C. Frostbite results from exposure to sub normal temperatures.
Definition of hyperthermia
Body temperature above 37.6°C.
Definition of hyperpyrexia
Extremely high body temperature above 41.5°C.
Definition of fever
Elevation in body temperature due to change in the hypothetical setpoint.
Fever represents a complex pathophysiological reaction involving the immune system in response to pyrogens that trigger the hypothalamus in the brain to adjust heat production, heat conservation, and heat loss mechanisms to maintain a higher core temperature, representing an increased hypothalamic set point.
Definition of febrile
A person with a fever
Definition of heat stroke
When prolonged exposure to high environmental temperatures overwhelms the bodies heat loss mechanisms.
Definition of heat exhaustion
When extreme or prolonged exposure to high environmental heat leads to profuse sweating, and consequent water and electrolyte loss.
Where is thermoregulation regulated?
The hypothalamus
Describe normal body temperature fluctuation throughout the day.
Body temperature in the middle of a persons, usual sleeping time will normally be lower, then begins to rise with their normal waking time, and peaks again late in their usual activity. Decreasing again around the persons usual bedtime.
True or false? Body temperature is controlled by the dynamic balance of heat production, conservation, and heat loss.
True
Explain body temperature
Body temperature is the difference between the amount of heat produced by body processes and the amount of heat lost to the external environment.
Facts regarding heat production
Food is the primary fuel source for metabolism.
The amount of heat produced is related to the rate of metabolism.
Factors that can increase heat production:
Exercise
Increased release of epinephrine and norepinephrine
Increased production of thyroid hormones
Definition of core temperature
Temperature of deep tissues
Heat loss is consistent through:
Radiation
Conduction
Convection
Evaporation
Define radiation as it relates to heat loss
The transfer of heat as waves or particles of energy.
Define conduction as it relates to heat loss:
The transfer of and reaction to heat through direct contact.
Define convection, as it relates to heat loss:
The transfer of heat by the movement, or circulation of warm matter, such as air or water.
Define evaporation as it relates to heat loss:
The process by which a liquid is changed to a vapor through heat.
Evaporation lowers body temperature.
Three mechanisms that lead to hyperthermia:
Excessive heat production
Inadequate ability to cool
Hypothalamic regulator dysfunction
Physiological factors that can lead to hypothermia:
Excessive heat loss
Insufficient production of heat
Dysfunction of hypothalamic regulatory mechanisms.
True or false? Hypothermia can be accidental or therapeutic.
True
True or false? Individuals experiencing significant hypothermia have been known to remove clothing because of reduced cognition, and because the vasodilation create a false warming sensation.
True
Three-step process outlining the consequences of hypothermia:
- Prolonged peripheral vasoconstriction
- Tissue ischemia
- Tissue necrosis, or death.
Consequences of elevated body temperature:
-Excessive and prolonged sweating
-Sodium loss, leading to dehydration, if fluid replacement does not occur
-Hypotension
-Tachycardia
-Decreased cardiac output, leading to reduced perfusion and coagulation
-Cardiovascular collapse
Examination findings of hypothermia:
Shivering
Cold
Cyanosis
Poor coordination
Achy
Slow cap refill
Decreased or absent, peripheral pulses
Examination findings in hyperthermia:
Sweating
Flushed
Dry, mucus membranes
Confused
Bounding pulse
Decreased urinary output
Nausea
Vomiting
Skin tenting
Increased heart rate
Interventions for hypothermia:
Remove the person from cold
Provide external warming measures: warm blanket
Provide internal warming measures, warm IV fluids, or warmed oxygen
Rewarming, safety tip!
Rewarming must be done slowly to minimize the risk for dysrhythmias. Cardiac monitoring is required when patient is recovering from severe hypothermia.
Intervention strategies for hyperthermia:
Remove excess clothing and blankets
Provide external cool packs
Provide a cooling blanket
Hydrate with cool fluids
Lavage with cool fluids
Administer antipyretic drug therapy
The five common sites for assessment of body temperature:
Mouth
Ear
Rectum
Forehead
Axilla
Temperature variation of a temperature taken orally (mouth):
36°C to 37.6°C.
(96.8°F to 99.68°F)
Temperature variation for axillary temperature (arm pit):
35.5°C to 37°C
(95.9°F to 98.6°F)
Temperature variation for rectal temperature (anus):
34.4°C to 37.8°C
(93.92°F to 100.04°F)
Temperature variation for tympanic temperature (ear):
35.6°C to 37.4°C
(96.08°F to 99.32°F)
Temperature variation for temporal temperature (forehead):
36.1°C to 37.3°C
(96.98°F to 99.14°F)
True or false? It is OK to obtain an oral temperature from someone who is eating, drinking, smoking, and/or using oxygen by cannula or mask.
False
When to NOT obtain an oral temperature:
It is not a preferred site for infants and young children, unconscious patients, post oral surgery patients, or people with seizure disorders
True or false? Rectal temperature readings are considered to be very accurate.
True
True or false? The rectum is the preferred temperature reading site of patients.
False
When is obtaining a rectal temperature contraindicated?
In newborns, in patients who are neutropenic, and in patients with spinal cord injury. It should not be used for patients with diarrhea or rectal disease, post rectal surgery patients, or quadriplegic patients.
True or false? A tympanic temperature is appropriate if there is draining from the ear.
False
How to obtain an accurate tympanic reading for an adult:
Gently pull up and back on the ear. Place the covered probe snuggly in the ear canal, angling it toward the jaw line before activating the sensor.
How to obtain an accurate tympanic temperature for a younger child, less than three years old:
Gently pull the ear down and back. Place the covered probe snuggly in the ear canal, angling it toward the jaw line before activating the sensor.
Evaluating a temperature reading includes:
The nurse must compare the temperature measurement obtained against any baseline data, previous readings, and the normal range for the patient.
