Thermoregulation

Thermoregulation basics

Core temperature is a balance between heat produced by
the body and heat loss to the surrounding environment.

The normal average temperature of an individual is 37+/-0.5
C.

Body temperature regulation is by the hypothalamus and
gets maintained by a variety of autonomic mechanisms. The
hypothalamus receives input from central and peripheral
thermal receptors

Hyperpyrexia (fever) assessment

- Vasodilatation = skin flushing & warmth
- Increased metabolic rate = thirst, ↑HR, ↑RR
- Fatigue, malaise, irritability, anorexia

Febrile seizures

- Due to rapid temperature increase > 39°C
- No evidence of CNS infection / disease
- Highest incidence less than 5 years
- Antipyretics will not prevent a febrile seizure!!

Hyperpyrexia

Identify if caregivers have used any prior
interventions to control fever

Identify learning needs regarding non-
pharmacological and pharmacological
interventions to control fever.

Identify learning needs related to indications to
seek healthcare provider evaluation vs home
management.

Identify contributing factors to fever than can
be eliminated:
- Heavy clothing, blankets, elevated room
temperature etc.

Hyperpyrexia interventions nonpharmacologic

Have child wear minimum clothing
Reduce room temperature
Apply cool, moist compresses to the skin
- Prevent shivering!
Cuddle / provide emotional support
Reassess Temperature 30 minutes after antipyretic
Monitor VS & Fluid Balance

Hyperpyrexia interventions pharmacological

Treatment is not always indicated
NO ASPIRIN = Reye’s Syndrome
Common Antipyretics & Dosing:
- Acetaminophen 10-15mg / kg / every 4-6 hours
PO / Rectal
- Ibuprofen** 5-10mg / kg / every 6-8 hours PO
** children > 6 months

Hyperpyrexia interventions when to seek emergency treatment

- Child is less than 2 months old
- Current chronic disease (Diabetes, CHF, Heart
Conditions, Immunosuppression / HIV / Sickle Cell)

Hyperpyrexia interventions call your doctor if…

- Fever for > 24hours without obvious cause
- Fever > 3 days
- Burning pain with urination
- History of febrile seizures
- Fever returned after 24 hour absence

Hypothermia

An involuntary drop in body temperature below 35C.
Etiology: Body loses more heat than it absorbs or creates, leaving
the body unable to generate sufficient heat to maintain
homeostasis and proper bodily function

Newborns at a greatest risk of heat loss

• A large surface area-to-body mass ratio
• Decreased subcutaneous fat
• Greater body water content
• Immature skin leading to increased evaporative water and heat losses
• Poorly developed metabolic mechanism for responding to thermal stress (e.g. no shivering)
• Altered skin blood-flow (e.g. peripheral cyanosis)

Most cooling of the newborn occurs immediately after birth.
During the first 10 to 20 minutes, the newborn may lose enough
heat for the body temperature to fall by 2-4°C if appropriate
measures are not taken.

Hypothermia patho

In response to increased cold stress, the hypothalamus will work to raise its metabolic heat production through a variety of mechanisms.
- Initial muscle tone and basal metabolic rate increase, which can double heat production.
- Shivering can also increase the heat production rate 2 to 5 times from baseline.
- Increase in thyroid activity, catecholamines, and adrenal response.
- Vasoconstriction of peripheral vessels
- Increased metabolism, ventilation, and cardiac output

Heat loss mechanisms

Radiation

Conduction

Convection

Evaporation

Radiation

Occurs when electromagnetic energy transfers between each other.

Conduction

Occurs when the heat gets transferred between two objects that are in contact with one another.

Convection

occurs when air molecules move past an object.

Evaporation

endothermic reaction that causes a liquid to form a gas.

Hypothermia assessment newborns

- Acrocyanosis and cool, mottled, or pale skin
- Hypoglycemia
- Bradycardia
- Tachypnea, restlessness, followed by shallow and irregular respirations
- Respiratory distress, apnea, hypoxemia, metabolic acidosis
- Decreased activity, lethargy, hypotonia
- Feeble cry, poor feeding

Hypothermia plan & intervention

Prepare to implement the “warm chain”, a set of
interlinked procedures to be performed at birth and during
the next few hours and days after birth in order to minimize
heat loss in all newborns:
1. Warm delivery room (at least 25°C & free from the drafts from
open windows, doors, or fans.)
2. Immediate drying after birth with a warm towel or cloth
3. Skin-to-skin contact with the mother
4. Initiate breastfeeding as soon as possible, preferably within 1 hour after birth
5. Postpone weighing and bathing at least 6-8 hours after birth
6. Dress newborn in appropriate clothing/blanket
7. Keep mother and newborn together 24 hours a day (rooming-in), in a warm room (at least 25°C)
8. Provide warm transportation (clothing, cap, & blanket)

Acetaminophen

10-15 mg/kg 4-6 hours

Ibuprofen

5-10 mg/kg 6-8 hours