Thermoregulation Flashcards
Normal Thermoregulation–Heat Production
- basal metabolism
- muscular activity (shivering)
- Thyroxine and epinephrine (stimulating effects on metabolic rate)
- temperature effect on cells
Normal Thermoregulation–Heat loss
- radiation
- conduction/convection
- evaporation (vaporization)
Factors affecting heat production
- basal metabolic rate
- muscle activity
- thyroxine output
- fever increase
- epinephrine, norepinephrine, stress response
Radiation
through electromagnetic waves (sunlight)
Conduction
through direct touch
Convection
through gas or liquid (heat rising/hot air balloon)
Evaporation
liquid changes to gas (boiling water)
Core Temp is controlled by
hypothalmus
3 processes that regulate temperature
- shivering (increase temp)
- sweating (decrease temp)
- vasoconstriction (increase temp)
Newborns Thermoregulation Considerations
- decreased subQ fat
- blood vessels are closer to surface (loose heat easily)
- brown adipose fat
- nonshivering themogenesis (a way to generate heat)
- preemies have less brown adipose fat
Children Thermoregulation Considerations
handle high temps well if healthy
Elderly Thermoregulation Considerations
- decreased subQ fat
- less active
- sensitive to extremes in environment temp
- Thermoregulation not as efficient
Normal Oral Body Temp
96.8 degrees F- 98.6 degrees F
Hypothermia
- excessive heat loss
- inadequate heat production
- impaired hypothalamic thermoregulation (brain damage)
- vasoconstriction and tissue ischemia
- vasoconstriction too long can cause gangrene (tissue death)
- 95.0 degrees F – 93.2 degrees F
Hyperthermia (not fever)
- body temp rises uncontrollably
- brain damage and death can occur
- delirium, convulsions, coma
- heat stroke/heat exhaustion
- may be due to neurological impairment/brain injury
- malignant hyperthermia (rare response to anesthesia, can be deadly, inherited, can be screened for genetic risk)
Fever
- adaptive response to pyrogen entering body (example: virus)
- controlled response by hypothalamus
- brain damage and death very rarely occur
- thermoregulation is not altered-fever can adversely affect critically ill patients
- raises BMR which will increase the demand for oxygen
Febrile Response: Chill phase
- body warms itself to raise core temp to new set point
- peripheral vasoconstriction, shivering, warmth-seeking behavior (start by feeling very cold)
Febrile Response: Flush Phase
- set point lowered to normal
- body cools itself-peripheral vasodilation, sweating, cool-seeking behavior
Benefits of fever
- fever is a protective mechanism (bacteria)
- enhances neutrophils and T-lymphocytes (viruses)
- slows growth of bacteria and viruses (they don’t replicate well at high fevers)
- may slow growth of certain tumors-may work better with penicillin
- early exposure to fevers caused by infections may protect children from asthma, allergies and cancer in adulthood
Culture and fever
- ethnic differences in parental management of fever-fever phobia in many cultures
- hispanics: more likely to believe fever can cause brain damage and death
- African Americans: more likely to over treat with ibuprofen and more concerned about febrile seizures
Nursing Care: Fever
- monitor temp every 2 hours as needed-promote adequate fluid intake
- monitor intake and output
- cover with sheet only-administer antipyretics as needed
- cool washcloth or ice bag to groin, axilla, forehead-cooling blanket
Clinical Manifestations: Fever
- cool skin when temp rising
- warm and flushed skin when temp decreasing
- increased heart rate
- increased respiratory rate
- oxygen need increases
- Febrile seizures-benign, common between 6 months-3 years, run in families, does not hurt brain
Temperature Variations
- Oral Temp: 98.6 degrees F
- Rectal Temp: 99.6 degrees F
- Tympanic Temp: 99.6 degrees F
- Axillary Temp: 97.6 degrees F
What is Fever?
- 100.4 degrees F or higher for rectal temp
- 101 degrees F oral-under 2-3 months-rectal temp 100.4 is considered fever and infant should be assessed for serious illness (blood, urine cultures, lumbar puncture)-lowest in morning and highest in the evening
Acetaminophen
-acts on hypothalamus, peripheral dilation-liver damage with overdose-tylenol, tempra-can be given every 4-6 hours-use with caution in liver disease
Ibuprofen
- nonsterodial anti-inflammatory drug (NSAID)-inhibits prostaglandin-advil, motrin-can be given every 6-8 hours over 6 months of age-use with caution with kidney disease
- CANNOT BE GIVEN UNDER 6 MONTHS OF AGE
Naproxen
- NSAID
- over 12 years of age
Aspirin (ASA)
- inhibits prostaglandin
- never to a child-linked to Reye Syndrome
Oral Temp (Advantages/Disadvantages)
- Advantages: accessible and convenient
- Disadvantages: thermometer can break if bitten; inaccurate if client has just ingested hot or cold food or fluid or has just smoked; could injure the mouth following oral surgery
Rectum Temp (Advantages/Disadvantages)
- Advantages: reliable measurement
- Disadvantages: inconvenient and more unpleasant for clients; difficult for client who cannot turn to the side; could injure rectum following rectal surgery; presence of stool may interfere with thermometer
Axillary Temp (Advantages/Disadvantages)
- Advantages: safe and noninvasive
- Disadvantages: thermometer must be left in place a long time to obtain an accurate measurement
Tympanic Membrane Temp (Advantages/Disadvantages)
- Advantages: readily accesible; reflects the core temp; very fast; may be less scary for small children
- Disadvantage: can be uncomfortable; involves risk of injuring the membrane if the probe is inserted too far; repeated measurements may vary; left and right measurements can differ; presence of wax can affect the reading
Temporal Artery Temp (Advantages/Disadvantages)
- Advantages: safe and noninvasive; very fast; less scary for small children
- Disadvantages: requires equipment that may be expensive or unavailable; variation in technique is needed if the client has perspiration on the forehead
