1. History of Thermoregulation
Incubation traced as far back as the Egyptians
Napoleon brought back to Parisian zoos
1800’s used for premature infants
1907 started use of temperature control

6. Basal Metabolic Rate
Human body produces heat as by-product of metabolism

7. Neutral Thermal Environment
Narrow range of environmental temperature
Infant is not required to adjust heat production above natural resting levels
Minimal oxygen consumption
Ultimate goal

8. Shivering and Sweating
Adults - Shivering is heat production from voluntary and involuntary rhythmic muscle activity. Sweating decreases heat by vasodilation and evaporation.
Neonates - Unable to produce heat by shivering. Infants < 30 weeks cannot sweat, and have 1/3 the response > 32 weeks.

9. Non-shivering Thermogenesis Brown Fat Metabolism
Brown Fat is Found:
Around the great vessels
Adrenal glands
Kidneys
Axillas
Nape of neck
Between the scapulas

10. Brown Fat Metabolism
Most important means of heat production in neonates
Present at weeks gestation & increases until weeks postnatal
Comprises 2.7% of total body weight in term infant
Cannot be replenished

11. Heat Transfer
Conduction
Radiation
Convection
Evaporation

12. Conduction Transfer of heat between solid objects in direct contact
Cold scale, circumcision board, mattress
Chemically activated warmers, heated water mattresses, skin-to-skin
> on metals, < on cloth

13. Convection
Transfer of heat to the air moving across and around the body
Varies based on temperature gradient, body surface exposed and speed of air movement

14. Evaporation Heat loss by conversion of liquid into vapor
Mainly transepidermal water loss (insensible)
As relative humidity  the water loss 
 with tachypnea, activity, radiant warmers and phototherapy
 as skin thickens and is less permeable

15. Radiation
Transfer of heat between solid objects that are not in direct contact
Surrounding walls and windows, including isolette walls
Accounts for 64% of the total dry heat loss in premature infants

16. Hypothermia
Short-term : Hypoglycemia, hypoxia, metabolic acidosis (metabolism of brown fat), anaerobic metabolism
Long-term : Impaired weight gain, RDS, heart failure, depletion of energy sources
At risk : Premature infants, small for gestational age, infants stressed due to sepsis, RDS, asphyxia

17. Hyperthermia
Causes : Overheating, phototherapy, sepsis, CNS disorders, dehydration, maternal fever

18. RCNIC Guidelines Core temperature 36.2 - 37.5°C
Axillary temperature °C
Abdominal skin temp °C
Temperature probes on abdomen or flanks
Use hats & socks

19. Radiant Warmer Reflective covers on temperature probes
Warm in non-servo (air-control) at maximum heat before admission
Servo control (patient control) with skin temp set at 36.5 °C

20. Isolettes Servo control for < 1250 grams
Non-servo control >1250 grams
Avoid obstructing airflow

22. True Story
When the transport team in Denver started fixed wing air transport, they had difficulty keeping infants warm.
First trip: Full-term, preheated 37 °C incubator.

23. Second Transport Added 50 % humidity Increased incubator to 38 °C
Minimized time portholes were open
Preheated diapers and blankets

24. Third Transport
Heated airplane cabin to 35 °C (95 °F)