This document discusses fluid calculation and homeostasis in neonates. It notes that water and electrolyte balance is vital but different in neonates compared to older children and adults due to rapid developmental changes. It outlines the physiology of total body water, intracellular water, and extracellular water. It also discusses changes that occur at birth and how to assess hydration status in neonates through monitoring things like urine output, weight, physical exam findings and lab tests. Maintaining appropriate fluid and electrolyte balance is important for health in preterm infants.

1. FLUID CALCULATION IN
NEONATES
Mrs. Arifa T N
First year M.Sc Nursing, MIMS CON

2. Introduction
 Water and electrolytes are vital components of the
body at any age. The laws that regulate fluid and
electrolyte balance in the newborn are the same as
those that control this process in children and adults
 the newborn’s body water distribution is both
quantitatively and qualitatively different
 Furthermore, rapid changes occur at the time of
birth, and sick newborns pose additional challenges.
Consequently, water and electrolyte homeostasis is
of vital importance and special care is required to
maintain an appropriate balance, especially in very-
low-birth-weight (VLBW) infants.

3. Water
 Physiology.
 Water is the main component of the human body. It
is distributed both inside and outside the cells:
Therefore a practical simplification is to classify total
body water (TBW) as,
 intracellular water (ICW) and
 extracellularwater (ECW).
 ICW is the total amount of water in all the body’s
cells.
 ECW is the total amount of water outside the cells; it
comprises the water in the interstitial space and in
the intravascular space (plasma).

4. In each compartment, a main solute acts to keep water
in the compartment:
 The volume of the intracellular compartment is
maintained mainly by potassium salts and is
regulated by the Na-K cellular pump.
 The volume of the extracellular compartment is
maintained mainly by sodium salts and is regulated
by the kidneys.
 In the extracellular space, the volume of the
intravascular compartment is maintained main

5. Changes in Water distribution

8. Postnatal Adaptation
 Fluid management is easier if one remembers a few
simpleprinciples:
(1) to separate water from sodium requirements;
(2) to keep maintenance fluids separate from fluids
given to correct electrolyte abnormalities;
(3) to recognize the pattern of neonatal diuresis.
 Monitoring a newborn’s urine output(UOP) can help
to individualize fluid requirements

10.  Appropriate administration of fluid is important,
because both excessive fluid restriction and fluid
overload lead to clinical consequences.
 Excessive fluid restriction may lead to dehydration,
hyperosmolality, hypoglycemia, and
hyperbilirubinemia.
 In preterm infants, high volumes of parenteral fluids
have been associated with a higher incidence of
PDA, BPD, and necrotizing enterocolitis.

11.  It is important to realize that the occurrence of BPD
has been correlated with fluid volume administered
during the first 4 days of life.
 Maintaining the fluid and electrolyte balance,
therefore, is extremely important in preterm infants.
Close monitoring of clinical hydration, body weight,
UOP, and the serum sodium concentration should
allow the best possible decisions on fluid
administration

12. Assessment and Evaluation in Fluid and
Electrolyte Therapy
 The estimation of a patient’s fluid and nutritional
needs depends on the infant’s age and weight and
the disease process involved
 Fluid needs can be calculated using body weight,
body surface area, or caloric expenditure
 Caloric expenditure is an easy method in which the
infant’s caloric needs are calculated, and fluid and
electrolyte requirements are related to it.

13.  To begin these calculations, it must be
remembered that 1 kcal is the amount of heat
needed to raise 1 L of water 1°C.
 Caloric expenditures up to 10 kg = 100 cal/kg/24
hr.
 For example, a 1,700-g infant would expend 170
calories in 24 hours, whereas a 460-g infant would
expend 46 calories in 24 hours.
 This can be expressed as
Energy intake=
energy stored + Energy expended
+ Energy excreted

14.  Caloric expenditures can be modified by an increase
or decrease in body temperature and by specific
disease states.
 Caloric expenditure can be used to determine water
needs, because for every 100 calories metabolized,
100 mL of fluid is needed
 Water needs are determined by calculating IWL from
the skin and pulmonary system and actual losses
from the urine, stool, and sweat

16.  Fluids usually are calculated on a daily basis, taking
into consideration past losses, projected losses, and
maintenance requirements.
 Electrolyte requirements usually are calculated on
the basis of 100 calories metabolized:
 Sodium: 2 to 3 mEq/100 cal/24 hr (2–3 mEq/kg/d)
 Potassium: 1 to 2 mEq/100 cal/24 hr (1–2 mEq/kg/d)
 Standard IV solutions containing a predetermined
amount of sodium are routinely used in neonatal
intensive care units (e.g., 5% dextrose in 0.45%
NaCl) with potassium chloride and other electrolytes
or minerals added as indicated

17.  Caloric requirements cannot be met solely by the IV
solutions commonly used in NICUs (i.e., 5% or 10%
dextrose).
 These solutions are relatively low in calories, as
there are only 4 calories per gram of
glucosecarbohydrate).
 The number of calories in IV solutions is calculated
on a percent solution and based on grams per 100
mL. Therefore 5% dextrose in water (D5W) contains
5 g of dextrose per 100 mL of fluid, 10% dextrose in
water (D10W) contains 10 g/100 ml, and so on. To
carry this calculation further, D5W and D10W IV
solutions contain 20 and 40 calories, respectively
(D5W = 5 g/100 mL at 4 cal/g = 20 cal).

18.  An essential test of the infant’s response to IV
glucose therapy can easily be done at the bedside
with a urine dipstick and a few drops of urine
 Determination of the specific gravity is another
essential bedside test that requires only a few drops
of urine. The specific gravity, which normally is
between 1.008 and 1.012, is an early indicator of
hydration status.
 Fluid intake and output should be strictly monitored
to ensure adequate hydration

19.  UOP is monitored and calculated hourly over a 24-
hour period. It should be no less than 1 mL/kg/hr/d.
For example, for a 2-kg infant:
 UOP = 240 mL/24 hr = 10 mL/2 kg = 5 mL/kg/hr
 Weight is an important indicator of overall fluid
status. Infants are usually weighed daily

20.  The physical examination can reveal changes in the
infant’s fluid status and should be used in
conjunction with laboratory data to plan interventions
in fluid and electrolyte therapy.
 Color: Pink and well perfused, rather than pale and
mottled (indicates dehydration)
 Skin turgor: Good turgor, rather than “tenting”
(indicates dehydration) or edematous and shiny
(indicates fluid overload)
 Activity: Active with good tone, rather than lethargic
and hypotonic (indicates dehydration or
overhydration)
 Mucous membranes: Pink and moist, rather than
dry and gray (indicates dehydration)

21.  Fontanelles: Soft and flat, rather than depressed
(indicates dehydration) or tense and full (may
indicate overhydration)
 Vital signs: Heart rate, rhythm, blood pressure and
temperature within normal range for gestational age
 UOP: Normal (e.g., ~1 cc/kg/hr), rather than
excessive (indicates overhydration), diminished, or
absent (indicating dehydration)

22. Thank you