Anemia of Prematurity - Portal Neonatal

Clinical evaluation
• Weight factors
o Sudden changes in an infant's weight do not necessarily correlate with changes
in intravascular volume. An infant's weight rises significantly for a number of
reasons while intravascular volume has decreased. Examples include the longterm
use of paralytic agents and peritonitis, both of which can lead to increased
interstitial fluid volume and increased body weight but decreased intravascular
volume.
o While growth charts are valuable in following growth parameters and nutritional
status over time, they play little role in the daily management of fluid and
electrolyte balances.
• Skin and mucosa manifestations: Altered skin turgor, a sunken anterior fontanelle (AF),
and dry mucous membranes are not sensitive indicators of dehydration in babies.
Remembering that premature infants have poorly keratinized skin that leads to a marked
elevation in IWL is important.
• Cardiovascular signs
o Tachycardia can result either from too much ECF (as can be seen in congestive
heart failure [CHF]) or from too little ECF (as can be seen in hypovolemia).
o Although delayed capillary refill occurs in low cardiac output states, it also can
be seen in infants with peripheral vasoconstriction resulting from cold stress.
o Hepatomegaly can occur in neonates with ECF excess, especially in CHF.
o As a result of an infant's compensatory mechanisms, blood pressure (BP)
readings usually are normal, with mild or moderate hypovolemia. With severe
hypovolemia, hypotension is present almost invariably.
Laboratory evaluation
Depending on the clinical situation and the suspected etiology of fluid and electrolyte
derangements, some or all of the following tests may be warranted:
• Serum electrolyte, urea nitrogen, creatinine, and plasma osmolarity levels: Keep in mind
that over the first 12-24 hours, results of these tests may still reflect maternal values.
• Accurate total urine output and total fluid intake
• Urine electrolytes and specific gravity: If the infant is being treated with diuretics, such as
furosemide, results of these tests are difficult to interpret.
• Calculation of the fractional urinary excretion of sodium in relation to creatinine (FENa)
• Blood gas analysis: Metabolic acidosis may be a marker of inadequate tissue perfusion.
FLUID AND ELECTROLYTE MANAGEMENT Section 5 of 11
Management goals
FE management is a balancing act between intake and output. Primary goals are to maintain the
appropriate ECF volume, ECF and ICF osmolality, and ionic concentrations.
Allow the initial loss of ECF over the first week, as reflected by weight loss, while maintaining normal
intravascular volume and tonicity, as reflected by heart rate, urine output, and electrolyte and pH
values. Subsequently, maintain water and electrolytes while supplying requirements for body
growth. Individualize the approach rather than relying on a cookbook formula.