Thermoregulation

Thermoregulate

Process of maintaining core body temperature at a near constant value

Hypothalamus maintains body's what with temperature?

Maintains body homeostasis with temperature control

What else does the hypothalamus do?

-BP

-hunger

-thirst

-mood

-sex drive

-sleep

Afebrile

without fever

Febrile

-oral temperature 99.6 F (37.6 C) and above

-rectal temperature 100.4 F (38) and above

Fever

Abnormal elevation of temperature

Cause of fever

infection or inflammation

Release of which hormones when a fever is spiked

Release of prostaglandin E2 and pyrogens

What does the release of prostaglandin E2 and pyrogen raise?

Raises hypothalamic set point

What is the set point of hypothalamic?

Set point typical at normal range unless hormones prostaglandin E2 and pyrogens are release which results in a higher set point

Hyperthermia

elevation of temp not typically caused by change in hypothalamic set point

What causes hyperthermia?

environment and drug induced

Hypothermia

decreased temp below normal not caused by change in hypothalamic set point

What causes hypothermia?

environment and drugs that cause vasodilation

Normothermia

Normal body temperature

Pyrexia

Fever

Hyperpyrexia

temp 104 F (41 C) and greater

Factors Affecting Thermoregulation

-circadian rhythm

-activity

-age related

-environment

Radiation

the diffusion or dissemination of heat by electromagnetic waves

Example of radiating heat

infected knee

Conduction

The transfer of heat to another object during direct contact

Example of conducting heat

ice pack

Convection

the dissemination of heat by motion between areas of unequal density

Example of convection of heat

fan

Evaporation

the conversion of a liquid to vapor

example of evaporation

sweating

Cognitive state of hyperthermia

-confusion

-agitation

-impaired cognition

-coma

-hallucination

-seizures

-loss of appetite

Cognitive state of hypothermia

-coma

-confusion

-poor concentration

-loss of consciousness

-hallucinations

Hyperthermia temperatures

101 F to 104 F (38.3 C to 41 C)

Hyperthermia Vital Signs

-increased BP

-RR increased

-HR increased

Hypothermia Temperatures

Mild: 95 - 90 degrees (32.2 to 35 C)

Moderate: 90 - 82 degrees (28-32 C)

Severe: beloe 82 degrees (28 and below C)

Vital Signs for Hypothermia

-Increased RR

-Decreased BP

-Bradycardia

Who are at risk for hypothermia and hyperthermia?

Infants and elderly

Population at risk for hyperthermia

-Poor socioecoomic status

-Homelessness

-Older adults

-young children

-chronic illnesses

-strenuous activity

-hot environment

-outdoor workers

Population at risk for hypothermia

-diabetes

-hypothyroidism

-chronic disease

-malnutrition

-obesity

-cardio disease

-COPD

-Alcoholism

-perioperative patients

Medically Induced hyperthermia

Targeted for some applications in oncology

Medically induced hypothermia

-HIE (hypoxic ischemic encephalopathy)

-to protect brain after cardiac arrest minimizes brain damage and injury

What does the hypothalamus fail to do when hyperthermia occurs?

Fails to stop heat production or/and promote heat loss

What does the hypothalamus trigger when hypothermia occurs?

Triggers shivering, vasoconstriction, and increased metabolic activity to generate and conserve heat

Illness/Injury from Hyperthermia

-heat stroke

-heat rash

-heat cramps

-heat exhaustion

-dizzy

-weakness

-nausea

-thirsty

-confusion

-organ failure

-flush

-dry mouth

-losing fluid

-electrolyte balance

Injury/Illness from hypothermia

-shivering

-frostbite

-poor motor skills

-tissue falls off

-necrosis

-numbness

-confusion

-coma

-cardiac arrest

-impaired circulation

Clinical findings for hyperthermia

-vasodilation

-seizures

-body is attempting to lose heat by increasing blood flow to the skin

-warm skin, rosy cheeks

-decreased urine output

Clinical findings for hypothermia

-peripheral vasoconstriction

-conserving heat by increasing blood flow to our core and less blood flow to our extremities

Cardiovascular in hyperthermia

-decreased cardiac output

-higher heart rate

-dehydration

-less blood being pumped

Cardiovascular in mild hypothermia

minimal changes, tachycardia

Cardiovascular in moderate hypothermia

slow HR, Reduced CO

Cardiovascular in severe hypothermia

Bradycardia, Cardia arrest, hypotension

Treatment of hyperthermia

-reduced temp ASAP

-38 C or higher take clothes off

-40 C or is acute and an emergency

Treatment of hypothermia

-rewarm ASAP but SLOWLY

-passive rewarm (warm blankets, warmers over bed)

-active rewarm (bair hugger, warmed IV fluids {slowly})