1. Thermoregulation
Taylor, ch 25

2. Objectives
Please refer to page 3 of your Course Description under “Domain of the Individual.” There you will find the outcomes listed for Thermoregulation. These outcomes are:
Explain the principles and mechanisms of thermoregulation.
Describe nursing measures that promote heat loss and heat conservation.
List S/S and identify interventions for hypo and hyperthermia.

3. Objectives cont’d
We will be discussing the concept of thermoregulation—in other words, what it means and how temperature is regulated in the body.
We will also discuss hypo and hyperthermia and measures to control temperature.
We will not discuss how to take a temperature. That is covered in the Vital Signs lecture.

4. Thermoregulation How the body regulates heat loss and heat production.
Heat loss has to equal heat production in order for the body temperature to stay constant. They occur simultaneously.
Regulation is controlled by mechanisms in the body, the environment, and behaviors of the individual.

5. Temperature Regulation
Regulated by hypothalamus which has one part for heat loss, one for conservation.
Hypothalamus receives info from thermoreceptors in the skin and body core
Sends info to cerebral cortex (voluntary), sweat glands, blood vessels, and skeletal muscles (shivering)

6. Heat Loss Controlled by anterior hypothalamus Can occur 4 ways:
Radiation (loss from skin surface)
Conduction (direct contact between objects)
Convection (from air currents)
Evaporation (perspiration)

7. Which Is It?
Dilation of blood vessels causes heat loss by which method?
Jumping in a cool lake on a hot day can cause heat loss by which method?
Standing in front of an air conditioner can cause heat loss by which method?
Exercising can cause heat loss by which method?

8. Heat Production Controlled by posterior hypothalamus
Heat production can occur in three ways:
Increased metabolic rate from exercising, increased thyroid gland activity, or fever (10% for every degree)
Shivering (skeletal muscle contraction)
Nonshivering thermogenesis in newborns from metabolizing vascular brown tissue

9. Factors Affecting Temperature
Age
Exercise
Hormones
Circadian rhythm (Figure 32-2)
Stress
Environment
Nutritional status
Drugs, anesthesia
Alcohol, cigarettes
Hot and cold liquids
Illness/disease

10. Temperature Terms Pyrexia, febrile (elevated temperature)
Afebrile (absence of fever)
Hyperthermia (heat exhaustion, heat stroke)
Hypothermia (frostbite)
Antipyretic (against fever)
FUO (fever of unknown origin)

11. Anatomy of a Fever Pyrogens cause body temp to rise
Hypothalamus responds by raising the set point from 98.6 to a new level.
Body responds by heat-producing actions like chills and shivering.
When new set point is reached, temperature plateaus and body stops producing heat
Temp starts dropping d/t immune system, antipyretics, and/or antibiotics
Body responds by sweating, flushing to lose heat

12. Fever Patterns
Sustained—continuously elevated above normal with very little fluctuation
Remittent—continuously elevated above normal with spikes
Intermittent—fever spikes with returns to normal (<24h)
Relapsing—fever spikes with returns to normal (>24h)

13. Fever S/S Headache Hot, dry skin Flushed skin “Glassy” eyes Thirst
Malaise
Delirium

14. Fever Can Be Good! Important body defense Enhances immune system
Stimulates WBC production
Suppresses bacterial growth
Stimulates interferon which fights viruses
However, very high (>102.2) or prolonged fevers can be dangerous d/t stress on body

15. When Temperature Goes Awry
Hypothermia—prolonged exposure to cold overwhelms body’s ability to produce heat. May be mild, moderate, or severe and can lead to frostbite (frozen cells)
Hyperthermia—prolonged exposure to heat causes hypothalamus to lose ability to regulate temp. Can lead to heat exhaustion & heatstroke.

16. Symptoms of Abnormal Temps
Hypothermia
Temps <86 to 96.8
Falling VS
Shivering
Memory loss
Depression
Poor judgment
Cyanosis
Cardiac dysrhythmias
Unconsciousness
Hyperthermia
Temps up to 113
Low BP, high P
Diaphoresis?
Confusion
Delirium
Excess thirst
Nausea
Muscle cramps
Unconsciousness

17. Nursing Actions for Hyperthermia
Maintain optimum fluid volume status (po or IV) 3 L/d
Administer antipyretics and antibiotics if appropriate
Cooling blanket or cool wet towels
Irrigations of stomach or bowel
Rest
Light cover
Oscillating fans
Dry linens and clothing
Control environmental temp

18. Nursing Actions for Hypothermia
Remove wet clothes
Wrap in blankets; keep head and neck covered and warm
Lie next to warm person under blankets
Drink hot liquids if conscious
Avoid alcohol and caffeine