Anemia of Prematurity - Portal Neonatal

Fluid, Electrolyte, and Nutrition Management of
the Newborn
Last Updated: July 22, 2002
Synonyms and related keywords: enteral nutrition, neonatal fluids, neonatal electrolytes,
neonatal nutrition, FEN, FEN management in newborns, parenteral nutrition, total parenteral
nutrition, TPN
AUTHOR INFORMATION Section 1 of 11
Author: Namasivayam Ambalavanan, MD, Clinical Assistant Professor, Department of
Pediatrics, Division of Neonatology, University of Alabama at Birmingham
Namasivayam Ambalavanan, MD, is a member of the following medical societies: American
Academy of Pediatrics, Medical Association of the State of Alabama, and Southern Society for
Pediatric Research
Editor(s): Scott MacGilvray, MD, Associate Professor, Department of Pediatrics, Pitt County
Memorial Hospital; Robert Konop, PharmD, Director, Clinical Account Management, Ancillary
Care Management; Brian S Carter, MD, Associate Director, Associate Professor, Department
of Pediatrics, Division of Neonatology, Vanderbilt University Medical Center and Gateway
Medical Center; Carol L Wagner, MD, Associate Professor, Department of Pediatrics, Division
of Neonatology, Medical University of South Carolina; and Neil N Finer, MD, Director, Division
of Neonatology, Professor, Department of Pediatrics, University of California at San Diego
INTRODUCTION Section 2 of 11
This article describes important principles and specific methods of fluid, electrolyte, and nutrition
(FEN) management in newborns, particularly infants requiring special attention, including
premature, very low birth weight (VLBW), and extremely low birth weight (ELBW) neonates. FEN
management in the context of acid-base disorders (eg, acidosis, alkalosis, metabolic, respiratory,
mixed disorders), hypercalcemia, magnesium disorders, metabolic disorders, and complications
of total parenteral nutrition (TPN) are not discussed in this article.
FEN management is important because most infants in a neonatal intensive care unit (NICU)
require IV fluids. If inappropriate fluids are administered, serious morbidity can result from fluid
and electrolyte imbalances.
FLUID AND ELECTROLYTE PRINCIPLES Section 3 of 11
The principles of fluid and electrolyte balancing include the following points:
• Total body water (TBW) equals intracellular fluid (ICF) plus extracellular fluid (ECF).
• ECF equals ICF (plasma and lymph in the vessels) plus interstitial fluid (between cells).
• Characteristics of fluid changes
o Neonates are born with an excess of TBW, primarily ECF, which needs to be
removed.
o Adult bodies are 60% water (20% ECF, 40% ICF).
o Term neonate bodies are 75% water (40% ECF, 35% ICF), and term neonates
usually lose 5-10% of their weight in the first week.
o Preterm neonates have more water (at 23 weeks' gestation, 90% water
composed of 60% ECF and 30% ICF), and they may lose 5-15% of their weight
in the first week.