R1v: Discuss temperature regulation specific to the neonate
Definition:
Neonate = birth to 28 days
Infant = 28 days to 1 year
Thermoregulation = the tight control of core body temperature despite fluctuating ambient temperatures
Mechanisms for Neonatal Temperature Regulation
In the TMZ body temperature is maintained by changing position and alterations in skin blood flow
Heat Balance in the Neonate – differs cf adults due to:
- Heat Production
- BMR twice that of adults
- Therefore, must lose more heat to maintain body temp
- Heat Loss
- Smaller heat capacity → total mass of neonate is smaller, therefore total body heat energy is less.
- Insulation minimal (thin subcut tissue)
- Large SA:Vol → rapid heat loss, but also significant heat transfer to neonate in warming
- Evaporation → high evaporative loses bc of increased skin perm
- Insensible losses (especially with higher RR)
- Limited ability to control personal environment
Cold Stress in Neonates: Increased Symp NS stimulation = increase O2 & glucose consumption, Increased PVR, Increase R-to-L shunt, decreased peripheral perfusion & metabolic acidosis
Cold Responses
- VC = limited
- Shivering = not well developed
- Behavioural = crying, change in position (much less effective cf adults)
- Non Shivering Thermogenesis
- Increased amount of brown fat (6% of total body wt of neonate)
- Brown fat cells release Thermogenin
- Uncouples oxidative phosphorelation = release of heat
Warm Responses
- VD = limited
- Sweating = limited capacity
- Behaviour – crysing
Therefore, in a heat gaining environment, infants can only really dissipate heat via Insensible Losses → puts them at great risk of Hyperthermia