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Thermoregulation in Low Birth Weight (LBW)

Thermoregulation in Low Birth Weight (LBW)

The role of hypothalamus

Body temperature is almost entirely governed by the neural mechanisms, and almost all of this mechanism occurs through the center of the temperature setting located in the hypothalamus.

In newborns central regulator of body temperature is not functioning properly, making it easy to decrease body temperature, especially for cold environments.


Thermostat or temperature regulation maintained because of the balance between the heat lost through the environment, and heat production. Both of these processes activities regulated by the central nervous system, namely the hypothalamus.

With the principle of the heat balance of the newborn will try to stabilize the body temperature of the factors causing the loss of heat due to the environment.

At birth, the baby has a change of intra-uterine environment that is warm to extra uterine environment that is relatively cooler. This causes a decrease in body temperature of 2-3 ° C, especially heat loss due to evaporation of amniotic fluid in the baby's skin is not dried quickly. These conditions will spur the body to cool that would cause the response metabolism and heat production.

Heat setting in newborns related to metabolism and the use of oxygen.

In certain environments the maximum temperature limit, the use of oxygen and metabolism is minimal, therefore the body temperature must be maintained for the heat balance.
Term infants in a state without clothes can withstand ambient temperatures of about 32-34 ° C. While the limit in adults 26-28 oC. Therefore, normal newborns require a warmer environment temperature and the temperature of the environment must be properly maintained.

In newborn infants less subcutaneous fat and epidermis is thinner than in adults. The blood vessels in the baby very easily influenced by temperature changes in the environment and all this under the influence of the hypothalamus as a central regulator of temperature.

Fluidity on the baby's body to decrease the surface area so that it will accelerate the loss of heat. It is influenced baby body length, body surface comparison with the weight of the baby's age, all of which may affect the normal temperature limits. In infants with low birth weight (LBW) adipose tissue decreased slightly and flexibility, so that it requires a temperature hotter environments to achieve a normal temperature.
If the ambient temperature falls below the low temperature, the baby will respond by increasing oxygen and increase metabolism so it will increase heat production.

If the baby is in place that is open to cold environments can lead to exhaustion of glycogen reserves and cause acidosis.

Heat roduction or thermogenesis

In the open and cool environment of newborns require the addition of heat.

Babies have a physiological mechanism to increase heat production is affected due to: increased metabolic rate, muscle activity and chemical thermogenesis:

1. Basal Metabolic Rate

Basal metabolic rate is the amount of energy used by the body for absolute rest and waking state.
In newborns, body movement, shivering is an important mechanism for producing heat. Shivering movement occurs when the skin receptors decreases in cold ambient temperatures, and these conditions will be forwarded to the central nervous system that will stimulate the sympathetic nervous system to use brown fat reserves, which is the main source of heat to cope with cold stress.
The release of norepinephrine by the adrenal glands and local nerve ends in brown fat that cause triglycerides can be metabolized into glycerol and fatty acids. This fatty acid oxidation increases heat production. If the supply runs out, the brown fat metabolism response to cold state will be reduced.
Oxidation of fatty acids in infants depends on the availability of oxygen, glucose, Adenosine Tri Phosphate (ATP) and the baby's ability to transform into heat.
Baby's ability to produce heat to change the pathological state such as hypoxia, acidosis, and hypoglycemia.

2. Muscle Activity

Shivering is a form of muscle activity due to cold temperatures. Heat production occurs through an increase in metabolic rate and muscle activity. If the baby does not shiver, mean metabolic rate in infants is enough.

3. Chemical Thermogenesis

Due to the release of norephineprin and ephineprin by sympathetic nerve stimulation.

Pediatric Nurses