Anemia of Prematurity - Portal Neonatal

• Characteristics of insensible water loss
o Insensible water loss (IWL) is water loss that is not readily measured, and IWL is
water lost via evaporation through the skin (two thirds) or respiratory tract (one
third).
o IWL depends on gestational age; the earlier the gestational age of the preterm
infant, the greater the IWL.
o The magnitude of IWL also depends on the postnatal age. Since skin thickens
with age, the IWL decreases as neonates age.
o All other measurable sources of fluid and electrolyte losses need to be
considered as well. Sources include stool (eg, diarrhea and ostomy), nasogastric
(NG) or orogastric (OG) drainage, and cerebrospinal fluid (CSF), including
ventricular drainage.
• Renal function changes: Neonates have a decreased capacity to concentrate or dilute
urine in response to changes in intravascular fluid status, and they are at risk for
dehydration or fluid overload. The normal maturation of renal function that occurs with
increasing gestational and postnatal age also plays a role in determining fluid
requirements.
ASSESSING FLUID AND ELECTROLYTE STATUS Section 4 of 11
A number of conditions can impact neonatal renal function adversely. The presence of several of
these can be suspected on the basis of information found in the prenatal and neonatal history.
Maternal history
• A newborn's fluid and electrolyte (FE) status partially reflects the mother's FE status. For
example, excessive administration of oxytocin or hypotonic intravenous fluid (IVF) to the
mother can cause hyponatremia in the neonate at birth.
• Placental dysfunction (eg, from hypertension in pregnancy) can affect intrauterine growth
adversely. Infants who are growth retarded at birth (