Fluid and Electrolyte Therapy in the Very Low-birthweight Neonate

Abstract

The transition from fetal to neonatal life is associated with major changes in water and electrolyte homeostasis. Fluid and electrolyte management is particularly challenging for very preterm neonates in whom water loss is large, highly variable, and, in large part, not subject to feedback control. In addition, preterm neonates’ kidneys have a more limited ability to compensate for water and electrolyte imbalances than term neonates. Insensible water loss is a much larger component of the total water requirement in extremely preterm infants than in term infants. The weight loss seen in preterm infants during the first postnatal week results, in large part, from an abrupt and absolute decrease in total body water volume, and hyperkalemia is a common finding in the first 24 to 72 hours after birth. Fluid and electrolyte adaptation in most very low-birthweight newborns generally occurs in three phases, and awareness of the changes associated with each phase can aid clinicians in determining appropriate adjustments in fluid and electrolyte therapy.