This document discusses fluid and electrolyte management in newborns. It covers physiological aspects like changes in body water and electrolyte composition during development. It also discusses factors that affect insensible water loss in newborns like maturity, respiratory distress, and environment. The principles of fluid therapy include estimating fluid and electrolyte deficits, calculating replacement and maintenance needs, administering IV fluids, and monitoring the newborn. Specific clinical conditions that require special management like prematurity, respiratory distress, and diarrhea are also covered.

1. FLUID AND ELECTROLYTE
MANAGEMENT
IN
NEWBORN
By
Dr B VIKRAM SIMHA
Guide: Dr SANJAY CHATTREE

2. AIM :
to allow successful transition from the aquatic
environment of the uterus into the arid extra-uterine milieu
in the first days of life and
to replace losses of water and electrolytes so as to
maintain normal balance of these essential substances.

3. PHYSIOLOGICAL ASPECTS:
Urine osmolarity range : 50mmol/L to 600mmol/L (Preterm) and
800mmol/L(Term)
Acceptable Range : 300-400 mmol/L  2-3ml/Kg/Hr of UOP
Neonatal Kidney has limited capacity both to excrete and conserve
Sodium-so Na+ Supplementation required.
Newborn kidney has a limited capacity to excrete excess water and
sodium.
So overload of fluid or sodium in the 1st week of life  morbidities
like PDA, NEC and BPD
TERM
800
PRETERM
600

4. BODY COMPOSITION
CHANGES IN BODY WATER
SOLUTE DISTRIBUTION
WATER LOSS
NEUROENDOCRINE CONTROL

5. BODY COMPOSITION
CHANGES IN BODY WATER

6. 94% of Body WT
at 3RD MONTH OF GESTATION
78% at TERM
↑RENAL FUNCTION
ATRIAL NATRIURETIC PEPTIDE
TBW & ECW :
Preterm > Term
SGA > AGAPOST NATAL ECW CONTRACTION
ECW ↓ ICW ↑
ICW > ECW by 3 months of life

7. CHANGES IN BODY WATER AND ELECTROLYTE COMPOSITION
DURING INTRAUTERINE AND EARLY POSTNATAL LIFE
Gestational Age (Weeks)
Component 24 28 32 36 40 1 to 4Weeks
After Term
Birth
Total body water (%) 86 84 82 80 78 74
Extracellular water (%) 59 56 52 48 44 41
Intracellular water (%) 27 28 30 32 34 33
Sodium (mEq/kg) 99 91 85 80 77 73
Potassium (mEq/kg) 40 41 40 41 41 42
Chloride (mEq/kg) 70 67 62 56 51 48

8. Changes in body water during gestation and infancy
3rd
month

9. Distribution of body water in a term newborn infant

10. BODY COMPOSITION
CHANGES IN BODY WATER
SOLUTE DISTRIBUTION
WATER LOSS
NEUROENDOCRINE CONTROL

11. Ion distribution in the blood plasma, which represents extracellular
fluid, and in the intracellular fluid compartment.
ECF:
Plasma – Non plasma
(interstitial)
= PROTEINS

12. BODY COMPOSITION
CHANGES IN BODY WATER
SOLUTE DISTRIBUTION
WATER LOSS
NEUROENDOCRINE CONTROL

13. WATER LOSS
SENSIBLE INSENSIBLE
Kidney GIT Skin
70%
Respiratory
Tract
30%

14. PHYSIOLOGICAL WEIGHT LOSS:
Salt and Water Diuresis (48-72 hrs)
Fluid Shift ICF  ECF
Weight Loss
ECF: Preterm > Term Weight Loss : Preterm (15%) > Term (10%)

15. INSENSIBLE WATER LOSS:
Insensible Water Loss according to
Birth Weight on Day 5
BIRTH WEIGHT IWL (ml/Kg/day)
<1000 gm 60-80
1000-1500 gm 40-60
>1500 gm 20

16. FACTORS AFFECTING INSENSIBLE WATER LOSS IN
NEWBORN INFANTS
Factor Effect On Insensible Water Loss (Iwl)
Level of matuqity
Inveqsely pqopoqtional to biqth weight
and gestational age
Respiqatoqy distqess (hypeqpnea)
Respiqatoqy IWL incqeases with qising
minute ventilation when
dqy aiq is being
bqeathed
Enviqonmental tempeqatuqe above
neutqal theqmal zone Incqeased in
pqopoqtion to incqement in tempeqatuqe
Elevated body tempeqatuqe
Incqeased by up to 300%
Skin bqeakdown oq injuqy Incqeased by
unceqtain magnitude
Congenital skin defect
(e.g.,gastqoschisis, omphalocele,

17. FACTORS AFFECTING INSENSIBLE WATER LOSS IN
NEWBORN INFANTS
Factor Effect On Insensible Water Loss (Iwl)
High ambient oq inspiqed humidity Reduced
by 30% when ambient vapoq pqessuqe Is
incqeased by 200%
Plastic heat shield Reduced by 30%
to 70%
Plastic blanket oq chambeq Reduced
by 30% to 70%
Semipeqmeable membqane Reduced by
50%
Topical agents Reduced by 50%

18. INSENSIBLE WATER LOSS:
PREVENTION > CURE (REPLACEMENT)
IWL  PRETERM>TERM
Reasons : Immaturity of Skin Barrier
Respiratory Distress
greater skin blood flow
larger body water
*ESSENTIAL FATTY ACID DEFICIENCY
MEASURES : INCUBATOR HUMIDIFICATION SYSTEMS
PLEXIGLASS HEAT SHIELDS
THIN BARRIERS OF SARAN
THIN PLASTIC BLANKETS
SEMIPERMEABLE MEMBRANES
WATER PROOF TOPICAL AGENTS

19. BODY COMPOSITION
CHANGES IN BODY WATER
SOLUTE DISTRIBUTION
WATER LOSS
NEUROENDOCRINE CONTROL

20. NEUROENDOCRINE CONTROL:
Pituitary : ADH & ACTH
Adrenal : Aldosterone
activators : RAS, ACTH, Na + ,K+
 but poor response of TUBULES
Parathyroid : PTH (↑)
vs  Ca2+
Thyroid : Calcitonin (↓)
ANF : Na+ and H2O excretion  Postnatal Diuresis

21. PRINCIPLES OF THERAPY:
Estimate
Calculate
Administer
Monitor
Replacement of Deficits
Maintenance
Replacement of
ongoing losses

22. Estimate
FLUID ELECTROLYTE
½ CATIONS(¼ SODIUM
+ ¼ POTASSIUM)
½ ANIONS
Dehydration
Isotonic Na+= 130-150
Hypertonic  Na+= >150
Hypotonic  Na+= <130
***From clinical
symptoms and
signs
E.g.
1.Severe acute diarrhea – isotonic
2.High IWL – hypernatremic
3.Inadequate salt loss replacement
– hypotonic.

23. Calculate
Replacement Maintenance
Rapid correction
Exception : Hypertonic Dehydration
Na+ correction over 24 hrs
K+ correction over 48-72 hrs.
Ongoing losses
Vomiting / Diarrhea/ RTA

24. DEFICIT – REPLACEMENT:
 Dehydration:
Moderate (10%) to Severe(15%)
correction over 24hrs
N/2 ½ in 8hrs + ½ in 16 hrs
+
Maintenance in 24 hrs
(N/5 + 10% D @ 100ml/Kg/day)
 Shock:
Stat NS @ 10-20 ml/Kg in 1-2 hrs
↓
Correction  ½ in 8hrs + ½ in 16 hrs
+
Maintenance

25. Type of
Dehydration
Serum
Sodium
Concentration
(mEq/L)
Calculation of
Total Solute Deficit
(mOsm/kg)a
Solute
Deficit
(mOsm/kg)
Sodium
Deficit
(mEq/kg)
b
Isotonic
(10%)
140 (0.7 ×280)–(0.6× 280) 28 14
Hypertonic
(10%)
153 (0.7 ×280)–(0.6× 306) 12 6
Hypotonic
(10%)
127 (0.7 ×280)–(0.6× 254) 44 22
a Total solute deficit = (TBWe × solutee - (TBWo × soluteo), where subscripts e and o indicate
expected and observed, respectively.
TBW e =0.7 L/kg; TBW o = 0.7 - 0.1 = 0.6 L/kg; solutee 140 × 2 = 280 mOsm/L, assuming total
solute concentration in body water is twice the sodium concentration in serum;
Solute o = observed serum sodium × 2.
b Total solute deficit is assumed to be half sodium. Although the serum (and ECW) has lost this
amount of sodium, only half this amount has been lost to the environment; the other half has
been lost into the cells in exchange for potassium, which in turn has been lost from the body.
In practice, therefore, only half the amount listed as “sodium deficit” should be replaced
as sodium, and the other half should be given as potassium. TBW, total body water.
ECW, extracellular water.
TABLE 21-5 CALCULATION OF SODIUM DEFICIT

26. GUIDELINES FOR FLUID THERAPY: TERM
Birth Weight Day 1 Day 2 to Day 7 Day 7
>1500 gm 60 (+15-20) 150
1000-1500 gm 80 (+10-15) 150
Day 1 : Solutes Excreted  15 mmol/Kg/day
Acceptable Urine Osmolarity  300mmol/L
 Minimum UOP required  50ml/Kg/day
+ IWL 20ml/Kg/day
--------------------------------
Total 60-70ml/Kg/day
10% D @ 4-6mg/Kg/min
Day 2 : Solute load increased + Fecal Losses + Growth Requirement
 +15-20ml/Kg/day
 + Na+, K+ after 48 hrs
Day 7 : 150-160 ml/Kg/day
DAILY FLUID REQUIREMENTS DURING 1ST WEEK OF LIFE (ml/Kg/day)

27. GUIDELINES FOR FLUID THERAPY: PRETERM
Day 1 : UOP PRETERM = TERM
but ACCORDING TO BODY WEIGHT THE LOSS IS PRETERM > TERM
so fluid req. PT > TERM
 80ml/Kg/day
10% D @ 4-6mg/Kg/min
Day 2 :  +10-15ml/Kg/day
 + Na+, K+ after 48 hrs
Day 7 : 150-160 ml/Kg/day
+Na+ supplementation @ 3-5 mEq/Kg upto 32-34 corrected weeks

28. 1.Birth weight : Term  1-3% per Day / 5-10% first week
Preterm2-3% per Day / 15-20% first week
Increased loss  fluid correction
Decreased loss  fluid restriction
2.Clinical Examination : signs unreliable
10% dehydration-signs of dehydration
15% dehydration-shock
3.Serum Biochemistry : Na+ & plasma osmolarity
Normal 135-145mmol/L
Na+
HypernatremiaHyponatremia
Weight: + - + -
Disturbance : H2O excess Sodium
Depletion
Salt and H2O
overload
Dehydration
Treatment: Fluid Restriction Sodium
Replacement
Salt andFluid
Restriction
Fluid correction
(48 hrs)
Monitor:

29. 4.Urine Parameters :
Acceptable Range:
Output  1-3ml/Kg/hr
Specific Gravity  1.005-1.012 (by Dipstick or Refractometer)
Osmolarity  100-400 mOsm/L (Freezing point osmometer)
5.Blood Gas : Poor perfusion and Shock  Metabolic Acidosis
6.Fractional Excretion of Na+: assess Renal Tubular Function
limited value in Preterm (immaturity)
7.Serum Creatinine, BUN : assess Renal Function
exponential fall in Serum Creat ( excretion of Maternal )
serial samples – better indicator  Renal failure
Monitor:

30. LABORATORY GUIDELINES:
IV FLUIDS:
ELECTROLYTES:
↑ ↓
> 3% per day or
> 20% cumulative
Weight loss < 1% per day or
< 5% cumulative
> 145 mEq/L Serum Na+ < 130 mEq/L
> 1.020/
> 400 mOsm/L
Urine
Specific Gravity/
Osmolarity
< 1.005/
< 100 mOsm/L
< 1 ml/Kg/hr UOP > 3ml/Kg/hr
ELECTROLYTE RECOMMENDATION
Na+ After 48 hrs
@ 2-3 mEq/Kg/dayK+
Ca2+ For first 3 days in high risk
conditions
@ 4 ml (40 mg)/Kg/day
Dextrose
10%
5%
@ 4-6 mg/Kg/min
If ≥1250 gm
If <1250 gm
EONH:
-> Premature(<32wks)
-> Preeclampsia
->IDM
->Perinatal Asphyxia (Apgar<4 @ 1 min)
-> Maternal Hyper PTH
->IUGR
->Iatrogenic alkalosis

31. SPECIFIC CLINICAL CONDITIONS:
1.Extreme Prematurity : < 28 wks
<1000 Kg
- large IWL upto 1-2 wks till Stratum Corneum matures
- ↓ requirement by ↓ing loss
- 5% D ; electrolyte free on day 1
- Na+ K+ supplementation after 48 hrs
2. RDS :
RDS hypoxia  ACIDOSIS  ↓ RENAL FUNCTION
+VE PRESSURE VENTILATION  ↑ ALDOSTERONE & ADH H2O Retention 
Symptomatic PDA.
3. Perinatal Asphyxia & Brain injury:  SIADH
↓
HYPONATREMIA
=> FLUID RESTRICTION (2/3RD Maintenance till Na+  normal)
Renal Parenchymal Injury  ATNOliguric or Anuric RF
↓ FLUID(only replace IWL & Metabolic Requirement) @ 40ml/Kg or 400ml/m2
At RECOVERY --Na+ K+ losses –to be calculated n replaced
4. Diarrhea :
 of FLUID DEFICIT over 24 hrs
 Ongoing losses @ 6-8 hrs

32. FLUID RESTRICTION:
Cochrane meta-analysis:
Restricted fluid therapy
Greater Wt loss + dehydration ↓ incidence of PDA, NEC & DEATH

33. Water
(mL)
Sodium
(mEq)
Potassium
(mEq)
Deficit 300 21 21
Maintenance 300 6 6
Ongoing losses 0 0 0
Total 600 27 27
Total/kg 200 9 9
a Water deficit: 0.10 × 3 kg.
b Electrolyte deficits calculated as in Table 21-5 (14 mEq/kg × 3 kg
divided between sodium and potassium).
c Potassium deficit should be replaced slowly over 48 to 72 hours.
d Maintenance water requirement assumed to be 100 mL/kg/day.
TABLE 21-7 CALCULATION OF FLUID AND ELECTROLYTE INTAKE FOR
A 3-KG INFANT WITH 10% ISOTONIC DEHYDRATION