Perioperative Metabolic Care of the Term and Preterm Infant

This chapter discusses perioperative fluid and electrolyte therapy and enteral and parenteral nutrition for the full-term and premature neonate. The immaturity of the neonatal renal system and hypothalamic-pituitary-adrenal (HPA) axis and the postnatal development of these systems significantly affect fluid and electrolyte homoeostasis during infancy. Premature infants are deficient in endogenous nutrient stores as fetal accretion of calcium, phosphorus, carbohydrate, fat and protein predominantly occurs during the third trimester. Consequently, extremely low birth weight (ELBW) infants (<1,000 g) and infants with intrauterine growth restriction (IUGR) are at greater risk for hypoglycaemia during early postnatal life than are full-term neonates. Metabolic stress associated with sepsis, cardiorespiratory disease and surgery may further imbalance glucose homoeostasis leading to large swings in glucose.