SURGICAL RESPONSE OF NEWBORNS

Surgical Response of Newborns : The endocrine and metabolic response to surgical stress in newborns (Newborns) is characterized by catabolic metabolism. An initial elevation in cathecolamines, cortisol and endorphins upon stimulation by noxious stimuli occurs; a defense mechanism of the organism to mobilize stored energy reserves, form new ones and start cellular catabolism.

Cortisol circadian responsiveness during the first week of life is diminished, due to inmaturation of the adrenal gland. Cortisol is responsible for protein breakdown, release of gluconeogenic amino acids from muscle, and fat lipolysis with release of fatty acids. Glucagon secretion is increased. Plasma insulin increase is a reflex to the hyperglycemic effect, although a resistance to its anabolic function is present.

During surgical stress Newborns release glucose, fatty acids, ketone bodies, and amino acids; necessary to meet body energy needs in time of increase metabolic demands. Early postoperative parenteral nutrition can result in significant rate of weight gain due to solid tissue and water accumulation.

Factors correlating with a prolonged catabolic response during surgery are: the degree of neuroendocrinological maturation, duration of operation, amount of blood loss, type of surgical procedure, extent of surgical trauma, and associated conditions (hypothermia, prematurity, etc.).

They could be detrimental due to the Newborns limited reserves of nutrients, the high metabolic demands impose by growth, organ maturation and adaptation after birth. Anesthetics such as halothane and fentanyl can suppress such response in Newborns