1. Fluids and Electrolyte Management in Neonates
AHMED BAMAGA
MBBS
KAUH

2. FE Management in NB Essentials of life: Essentials of neonatal care:
Food (Nutrition)
Water (Fluid/electrolyte)
Shelter (environment control - temperature etc)
Essentials of neonatal care:
Fluid, electrolyte, nutrition management (All babies)
Control of environment (All babies)
Respiratory /CVS/CNS management (some babies)
Infection management (some babies)

3. Why is FE management important?
Many babies in NICU need IV fluids
They all don’t need the same IV fluids (either in quantity or composition)
If wrong fluids are given, NB kidneys are not well equipped to handle them
Serious morbidity can result from fluid and electrolyte imbalance

4. Fluids and Electrolytes
Priniciples:
Total body water (TBW) = Intracellular fluid (ICF) + Extracellular fluid (ECF)
Extracellular fluid (ECF) = Intravascular fluid (in vessels : plasma, lymph - IVF) + Interstitial fluid (between cells - IF)
Goals:
Maintain appropriate ECF volume,
Maintain appropriate ECF and ICF osmolality and ionic concentrations

5. Things to consider: Normal changes in TBW, ECF
All babies are born with an excess of TBW, mainly ECF, which needs to be removed
Adults are 60% water (20% ECF, 40% ICF)
Term neonates are 75% water (40% ECF, 35% ICF) : lose 5-10 % of weight in first week
Preterm neonates have more water (24 wks: 85%, 60% ECF, 25% ICF): lose 5-15% of weight in first week

6. Things to consider: Normal changes in Renal Function
Neonates are not able to concentrate or dilute urine as well as adults - at risk for dehydration or fluid overload
Solute conc in urine ranges mOsm/L in terms, in PT
Renal function matures with increasing:
gestational age & postnatal age

7. Things to consider: “Insensible” water loss (IWL)
IWL  not obvious: Skin (2/3) or Resp tract (1/3). Depends on:
gestational age (more PT: more IWL)
postnatal age (skin thickens with age)
also consider losses of other fluids: Stool (diarrhea/ostomy), NG/OG drainage, CSF (ventricular drainage).
SWL  that seen = urine+stool

8. “Insensible” water loss (IWL)
Birth wt
IWL(ml/Kg/D)
<1000gm
100 gm 60
>1500 20

9. Factors raising IWL So more fluids required Raised RR
High body/ambient temp = 30%/C
Warmers/PT  incr IWL 50%
Incr activity/crying
Skin loss, trauma, omphalocele, neural tube defects

10. Factors reducing IWL Incubators / humidified inspired gases
Plexiglass heat shield
Transparent plastic barriers – do not interfere in warmer functions  reduce water loss 30%

11. Assessment of FE status
History: baby’s F&E status partially reflects mom’s F&E status (Excessive use of oxytocin, hypotonic IV fluid  hyponatremia)
Physical Examination:
Weight: reflects TBW but not intravascular volume (eg. Long term paralysis and peritonitis  incr BW and incr IF but decreased intravascular volume.
Moral : a puffy baby may or may not have adequate fluid where it counts  in his blood vessels)

12. Weight loss
Term  1-2%/D total 10% loss
PT  2-3%/D total 15% loss
This is due to loss of ECW and needs no replacement

13. Assessment of FE status Physical examination (Contd)
Skin/Mucosa: Altered skin turgor, sunken AF, dry mucosa, edema etc are not sensitive indicators in babies
Cardiovascular:
Tachycardia  too much (ECF excess in CHF) or too little ECF (hypovolemia)
Delayed capillary refill  low cardiac output
Hepatomegaly can occur with ECF excess
BP changes very late
Urine output

14. Assessment of FE status Lab evaluation
Serum electrolytes and plasma osmolarity
Urine electrolytes, specific gravity (not very useful if the baby is on diuretics - lasix etc), FENa
Blood urea, serum creatinine (values in the first few days reflect mom’s values, not baby’s)
ABG (low pH and bicarb may indicate poor perfusion)

15. Management of F&E
Goal: Allow initial loss of ECT over first week (as reflected by wt loss), while maintaining normal intravascular volume and tonicity (as reflected by HR, UOP, lytes, pH). Subsequently, maintain water and electrolyte balance, including requirements for body growth.
Individualize approach (no “cook book” is good enough!)

16. Management of F&E - D1 Term
Req.= Urine + IWL – Wt loss
On IV fluids  solute load 15mOsm/Kg
With urine osmolality 300, urine=50ml/Kg
IWL = 20ml/kg
Wt loss = 10gm/Kg
Req.= – 10 = 60ml/Kg
PT  more IWL

17. Guidelines for FE Birth wt Fluid Day1 Day2 onwards 1500+ 10D 60 75
Add 15ml/D
1000 – 1500 80 95
<1000
5-10D + Na/K
100
115

18. Let there be lytes! Electrolyte requirements:
For the first 1-3 days, sodium, potassium, or chloride are not generally required
Later in the first week, needs are 1-2 mEq/kg/day (1 L of NS = 150+ mEq; 150 cc/kg/day of 1/4 NS = 5.9 mEq/kg/day which is too much)
After the first week, during growth, needs are 2-3 or even 4 mEq/kg/day

19. F&E in common neonatal conditions
RDS: Adequate but not too much fluid. Excess leads to hyponatremia, risk of BPD. Too little leads to hypernatremia, dehydration
BPD: Need more calories but fluids are usually restricted: hence the need for “rocket fuel”. If diuretics are used, w/f ‘lyte problems. May need extra calcium.
PDA: Avoid fluid overload. Keep at 120ml/Kg. If indocin is used, monitor urine output.

20. F&E in common neonatal conditions
Asphyxia: May have renal injury or SIADH. Restrict fluids initially, avoid potassium. May need fluid challenge if cause of oliguria is not clear.
NEC: Need more fluids. May go into shock. Give 200ml/Kg
ARF:Give 400ml/sq m/D + urine output

21. Common ‘lyte problems Sodium: Hypo (<130 mEq/L; worry if <125)
Hyper (>150 mEq/L; worry if >150)
Potassium:
Hypo (<3.5 mEq/L; worry if <3.0)
Hyper > 6 mEq/L (non-hemolyzed)
(worry if >6.5 or if ECG changes )
Calcium:
Hypo (total<7 mg/dL; ion<4)
Hyper (total>11; ion>5)

22. Hyponatremia
Sodium levels often reflect fluid status rather than sodium intake

23. Hypernatremia
Hypernatremia is usually due to excessive IWL in first few days in VLBW infants (micropremies). Increase fluid intake and decrease IWL.
Rarely due to excessive hypertonic fluids (sod bicarb in babies with PPHN). Decrease sodium intake.

24. Potassium stuff
Potassium is mostly intracellular: blood levels do not usually indicate total-body potassium
pH affects K+: 0.1 pH change=> K+ change (More acid, more K; less acid, less K)
ECG affected by both HypoK and HyperK:
Hypok:flat T, prolonged QT, U waves
HyperK: peaked T waves, widened QRS, bradycardia, tachycardia, SVT, V tach, V fib

25. Hypo- and Hyper-K Hypokalemia: Hyperkalemia:
Leads to arrhythmias, ileus, lethargy
Due to chronic diuretic use, NG drainage
Treat by giving more potassium slowly
Hyperkalemia:
Increased K release from cells following IVH, asphyxia, trauma, IV hemolysis
Decreased K excretion with renal failure, CAH
Medication error very common

26. Management of Hyperkalemia
Stop all fluids with potassium
Calcium gluconate 1-2 cc/kg (10%) IV
Sodium bicarbonate 1-2 mEq/kg IV
Glucose-insulin combination
Lasix (increases excretion over hours)
Kayexelate 1 g/kg PR (not with sorbitol! Not to give PO for premies!)
Dialysis/ Exchange transfusion

27. Calcium
At birth, levels are mg/dL. Drop normally over 1-2 days to in term babies.
Hypocalcemia:
Early onset (first 3 days):Premies, IDM, Asphyxia If asymptomatic, >6.5: Wait it out. Supplement calcium if <6.5
Late onset (usually end of first week)”High Phosphate” type: Hypoparathyroidism, maternal anticonvulsants, vit. D deficiency etc. Reduce renal phosphate load

28. Monitoring fluid therapy
Wt loss 1% /d ( loss > 2% /d = dehydration / gain > 1% /d = overhydration)
Urine : 1-3ml/kg/hr (< 1: dehydration , > 4 : overhydration / diuresis)
Na : mEq/L / K : 4-5 mEq/ L
Osmolality : mosm/L
Urine sp.gr. :
Blood glucose: mg/dl

29. Common fluid problems
Oliguria : UOP< 1cc/kg/hr. Prerenal, Renal, or Postrenal causes. Most normal term babies pee by hrs. Don’t wait that long in sick l’il babies! Check Baby, urine, FBP. Try fluid challenge, then lasix. Get USG if no response
Dehydration: Wt loss, oliguria+, urine sp. gravity > Correct deficits, then maintenance + ongoing losses
Fluid overload: Wt gain, often hyponatremia. Fluid+ sodium restriction

30. Thank you