Basic principles and practical steps in the management of fluid balance in the newborn.

The fluid management of newborn babies can pose many problems. This article discusses the factors that affect fluid balance in the newborn infant, both term and preterm, and the special circumstances of the surgical neonate. The main determinants of management are: (1) an estimation of transepidermal water losses; (2) an awareness of glomerular filtration rate and how this is influenced by age, respiratory distress and medical intervention; and (3) knowledge of tubular function and its maturation and the processes of postnatal adaptation. This knowledge and appropriate monitoring are the mainstay of management of neonatal fluid balance.