Pedram Niknafs, MD
Professor of Pediatrics
Director of Neonatal Services
Afzalipour Medical School
Kerman University of Medical Sciences
Kerman, Iran
Transition to Extrauterine Life
• Redistribution of body water
• Changes in renal function
- renal blood flow and GFR
- sodium balance
- water handling
• The kidney of a premature
infant is unable to maintain
positive water and sodium
balance without large intakes
of fluid and electrolytes.
• Growth
• Increased IWL
• Immature renal function
The Reasons for IWL in
Preterm Infants
• Immaturity of the
cornified layer of the skin
• Body surface/body mass
The Relationship Between
Metabolism and Maintenance Fluids
Route
mL/100 kcal
metabolized energy
• Insensible
40
- Skin
25
- Respiration
15
• Urine
80
• Stool
5
Total for Maintenance
125
Clinical Criteria
to Assess Hydration
• Body weight
(weight loss of 5% to 15% in term and
VLBW infants respectively)
• Skin turgor
• Edema
• Fontanelle
• Oral mucus membranes
Laboratory Criteria
to Assess Hydration
• Urine volume
(1-3 mL/kg/h)
• Serum sodium
• Urine osmolality
(150-400 mOsm/L)
• Urine specific gravity
(1006-1013)
A Practical Method to Calculate
Fluid Requirements (mL/kg/d)
Day
1
2
3
< 1000
100
120
140
1000-1500
80
100
120
> 1500
60
80
100
Adjustments depend on clinical and
biochemical assessment of hydration state.
Usually 120-150 mL/kg/d is adequate to
maintain hydration during the first two weeks.
Fluid Therapy in the
Neonatal Period (mL/kg/d)
Maintenance
phototherapy
Renal concentrating defect
Acute renal failure
Mechanical ventilation
Congestive heart failure
Total
Depending on age and WT
+ 20
- 60 + urine volume
- 70 + urine volume
- 10
- 30
............
Factors That Dramatically
Change the Fluid Requirements
• Critically ill newborn infants
• Environmental stresses:
- radiant warmer
- phototherapy
• Immature organ function
• Transition to extrauterine life
1. Severe prematurity, 100-300%
2. Open warmer bed, 50-100%
3. Forced convection, 30-50%
4. Phototherapy, 30-50%
5. Hyperthermia, 30-50%
6. Tachypnea, 20-30%
1. Humidification in incubator, 50-100%
2. Plastic heat shield in incubator, 30-50%
3. Plastic blanket under radiant warmer,
30-50%
4. Tracheal intubation with
humidification, 20-30%
• Urine output <0.5 mL/kg/h
• Serum sodium 150 mEq/L
• Body weight loss approaches 15% of
birthweight
• Baby is appearing dehydrated (color,
perfusion, turgor, anterior fontanelle)
•
•
•
•
Urine output >4 mL/kg/h
Serum sodium <130 mEq/L
Body gain in the first 3 days of life
Body is edematous with otherwise
adequate hemodynamics (color,
perfusion, heart rate, and blood
pressure)
•Na: 2 mEq/kg/day
•K: 2 mEq/kg/day
•Cl: 4 mEq/kg/day
• Initial Therapy
• Maintenance with restriction
• Liberalization of fluids
Stabilization
• Establish IV access
• Treat shock
• Prevent hypoglycemia
Maintenance with Restriction
• Least volume to prevent dehydration
Liberalization
• Rehydration
• Advance nutrition for growth
Complications of
Excessive Fluid Intake
•
•
•
•
Bronchopulmonary dysplasia
Patent ductus arteriosus
Necrotizing enterocolitis
Intraventricular hemorrhage
BPD
PDA
NEC
IVH
Calculation of Na Deficit
Serum Na
Concentration
(mEq/L)
Calculation of Total
Solute Deficit
(mOsm/kg)
Solute Deficit
(mOsm/kg)
Na Deficit
(mEq/kg)
Isotonic (10%)
140
(0.7 x 280) – (0.6 x 280)
28
14
Hypertonic (10%)
153
(0.7 x 280) – (0.6 x 306)
12
6
Hypotonic (10%)
127
(0.7 x 280) – (0.6 x 254)
44
22
Type of
Dehydration
Avery's: Neonatology, 6th edition, 2005: 793
Total solute deficit is assumed to be half Na.
Although the serum (and ECW) has lost this
amount of Na, only half this amount has
been lost in the environment; the other half
has been lost into the cells in exchange for K,
which in turn has been lost from the body. In
practice, therefore, only half the amount
listed as “Na deficit” should be replaced as
Na, and the other half should be given as K.
Avery's: Neonatology, 6th edition, 2005: 793
Hypernatremia: Therapy
• Increase free water administration to reduce
serum Na no faster than 1 mEq/kg/h.
• Hypernatremia does not necessarily imply
excess total body Na. For example, in the
VLBW infants, hypernatremia in the first 24
hours of life is almost always due to free
water deficits.
Cloherty JP, et al: Manual of neonatal care, 2012: 275
Physician’s Order
FLUIDS
mls/kg/day
…………… mls/day
…………… mls/hour
……………
Physician’s Order
ARTERIAL LINE: 500 mls D5W/Normal saline
Additives: 500 units Heparin
Rate of infusion: 1 ml/hour
Physician’s Order
IV 1: D5W/D10W/Protein solutions
Additives to ……………. mls
KCl ………. % ………. mls (K= 2 mEq/kg/d)
NaCl ………. % ………. mls (Na= 3 mEq/kg/d)
Ca gluconate 10% ………. mls
Rate of infusion …………… mls/hour
Physician’s Order
IV 2: Type: Intralipid 20% …… mls
Additives to ………….. mls
Rate of infusion ………….. mls/hour
Physician’s Order
IV 3:
Type:
Additives to …………… mls
………………………………………
………………………………………
Rate of infusion ……………. mls/h
Physician’s Order
ORAL FLUID INTAKE: EBM 4 mls 2/24
by 2 mls every 2nd feed
IV accordingly