F LUIDS, E LECTROLYTES, AND N UTRITION FOR THE N EONATE : Melissa Nelson, MD Neonatal-Perinatal Fellow Yale-New Haven Hospital.

FLUIDS, ELECTROLYTES, AND NUTRITION FOR THE NEONATE:Melissa Nelson, MD

Neonatal-Perinatal Fellow

Yale-New Haven Hospital

LECTURE OBJECTIVES:

Understand principles of fluid balance in neonates and appropriate postnatal fluid management

Learn concepts of electrolyte balance in neonates

Recognize signs and symptoms of certain electrolyte abnormalities and learn how to treat them

Learn about neonatal nutritional requirements and feeding methods

PRINCIPLES OF FLUID BALANCE:

TBW = ICF + ECF ECF = Intravascular + Interstitial

http://akramania.byethost11.com/OHCM/16%20-%20Clinical%20Chemistry.htm

TOTAL BODY WATER COMPOSITION:

Adult TBW = 60% (40% ICF + 20% ECF) Full-term TBW = 75% (35% ICF + 40% ECF) Pre-term TBW = 90% (30% ICF + 60% ECF)* Excess TBW esp. ECF at birth, hence diuresis within 1st week of

life (up to 10% in FT, up to 15% in pre-term)

http://www.revivenaturally.com/dr-yoshitaka-ohno-md-phd/maintaining-intracellular-hydration-water.html

SENSIBLE VS. INSENSIBLE WATER LOSS:

Sensible water loss (SWL): Easily measured Urine, stool, NG/OG output, CSF

Insensible water loss (IWL): Not readily measured Evaporation from skin (66%) or respiratory tract (33%) IWL greater in lower GA (immature skin) Factors that increase: Immature skin, fever, radiant

warmers, phototherapy, skin defects/breakdown Factors that decrease: Mature skin, humidity, heat shields

RENAL FUNCTION IN NEONATES: Decreased capacity to concentrate or dilute

urine in response to intravascular fluid status Risk dehydration or fluid overload

http://www.yalemedicalgroup.org/stw/Page.asp?PageID=STW028984

Adults: FENa < 1%

vs.

Term infants: FENa < 1%(except transient increase during diuretic phase)

vs.

Pre-term infants: FENa 5-6%

ASSESSING FLUID STATUS: Factors that can affect fluid status:

Maternal history: Neonate’s status reflects mother’s

Neonatal history (ie. In utero hypoxemia associated with ATN and hypervolemia)

Clinical evaluation: weight changes, UOP, IWL factors (humidity, phototherapy, ventilation, etc.), vital signs, perfusion

Laboratory evaluation: serum electrolytes, BUN/Cr

FEN MANAGEMENT: Goals:

Maintain ICF and ECF volumes and osmolalities Allowing diuresis within 1st week of life

Maintain appropriate electrolyte concentrations

Provide adequate nutrition for growth

TOTAL FLUID REQUIREMENTS: Total fluids = Maintenance + Growth

Maintenance = SWL + IWL

http://www.champ-sportsline.de/en/nutrients-active-ingredients/fluids.html

STARTING POINTS AND ADVANCEMENT:

Starting Points:BW < 1250g: TF = 80 - 100BW 1250-1750g: TF = 60 - 80BW > 1750g: TF = 60

Advancement Example: ELBW infant Start DOL 1 with TF = 100 Adjust daily to maintain wt loss within 10% BW DOL 2 with TF ~100-120 DOL 3-4 with TF ~120-130 DOL 4-5 with TF ~130-140 Goal TF ~140-150

FLUID ISSUES ASSOCIATED WITH COMMON NEONATAL CONDITIONS:

Issues requiring fluid restriction: RDS: Excessive fluid can lead to fluid overload and

increased risk of BPD BPD: Excessive fluid can worsen therefore treated

with diuretics to reduce pulmonary edema PDA: Volume overload can open ductus and

worsen respiratory status HIE: Associated with ATN and/or SIADH and can

lead to subsequent volume overload

COMMON FLUID PROBLEMS:

Hypervolemia/volume overload

Hypovolemia/dehydration

Oliguria: UOP < 1 mL/kg/hrPre-renal, Renal, Post-renal

ELECTROLYTE REQUIREMENTS: First 24h of life: No electrolytes (except Ca)

Ca especially important for preterm infants

At 24h of life: Na: 1-3 mEq/kg/day K: 1-2 mEq/kg/day

At 1 week of life: Na: 3-5 mEq/kg/day K: 2-3 mEq/kg/day

* Extremely pre-term infants with metabolic acidosis (loss of bicarb in urine) may benefit from sodium acetate

** Electrolyte requirements vary based on medications, etc.

COMMON ELECTROLYTE ABNORMALITIES:

Hypo/hypernatremia

Hypo/hyperkalemia

Hypocalcemia Hypermagnesemia

http://www.coconutwaterlife.com/electrolytes

SODIUM ABNORMALITIES:

Hyponatremia: Na < 130 mEq/L Causes: Usually due to excess free water but can

be increased Na losses/inadequate Na intake Signs/sx: lethargy, seizures, coma Tx: Restrict fluids and/or Na supplements

Hypernatremia: Na > 150 mEq/L Causes: Usually due to high water losses, rarely

excess intake Signs/sx: lethargy, seizures, coma Tx: Increase fluids and/or restrict Na

POTASSIUM ABNORMALITIES:

Hypokalemia: K < 3.5 mEq/L Causes: Diuretics, NG losses Signs/sx: EKG changes (flat T waves, prolonged QT,

U waves), arrhythmias, ileus, lethargy Tx: Slowly correct IV or orally

Hyperkalemia: K > 6 mEq/L Causes: Iatrogenic, severe acidosis, ARF, RBC

breakdown s/p transfusion, CAH Signs/sx: EKG changes (peaked T waves, wide QRS,

brady/tachycardia, SVT, V Tach, V fib), arrhythmias, death

Tx: D/C all K, Ca gluconate, sodium bicarbonate, albuterol, insulin + glucose, lasix, kayexalate, dialysis/exchange

* Most K is intracellular, thus serum levels might not accurately depict total body stores

** pH affects K levels: Acidosis drives K out of cell vs. Alkalosis pushes K into cell

CALCIUM ABNORMALITIES:

Hypocalcemia: Ca < 7 mg/dL (iCa < 1) Causes: Prematurity, IUGR, IDM, HIE,

hypoparathyroidism, Vitamin D deficiency Signs/sx: Asymptomatic, jitteriness, irritability,

seizures Tx: Observation, repletion (Ca gluconate), or

supplementation

Hypercalcemia: Ca > 11mg/dL (iCa > 5) Rare in neonates Usually associated with preterm fortifiers (HMF)

* Important to follow Ca levels as well as Phos and Alk Phos levels

~every 2 weeks once on full feeds to screen for osteopenia

MAGNESIUM ABNORMALITIES:

Hypermagnesemia: Mg > 2.3 mEq/L Causes: Maternal treatment with magnesium for

PEC or tocolysis Signs/sx: Respiratory depression, apnea, hypotonia,

decreased GI motility Tx: Self-limited, resolves within a few days

PRINCIPLES OF NUTRITION: Nutrient requirements:

Carbohydrates Protein Fat Water Minerals and trace elements Vitamins

ENERGY REQUIREMENTS: Depend on:

GA Postnatal age Weight Route of intake (less calories if parenteral) Growth rate Activity level Thermal environment Medical problems

Ideally energy from: 65% carbohydrate + 35% lipid

Protein building block for growth

ENERGY REQUIREMENTS:

Typical needs: 100-120 cal/kg/day for growth Term = 100 vs. Preterm = 120 cal/kg/day Many need more! (ie. BPD or CHD might need 160-180)

“Healthy” enterally fed premie: 125 cal/kg/dayResting energy expenditure: 50 cal/kg/dayActivity level (minimal): 5 cal/kg/dayOccasional cold stress: 10 cal/kg/dayStool loss (10-15% of intake): 15 cal/kg/dayGrowth (4.5 cal/g of growth): 45 cal/kg/day

METHODS OF PROVIDING NUTRITION:

Total Parenteral Nutrition (TPN):Peripheral vs. Central

Combination Parenteral/Enteral Nutrition:Advancing feeds but still giving TPN

Total Enteral Nutrition:Per oral route (PO) (ie. Bottle/breast)Per gavage route (PG) (ie. NG/OG on

pump)Chronic feeding tube feeds (ie. G-tube)

TOTAL PARENTERAL NUTRITION: Goal: Provide energy and nutrients to promote growth

when unable to adequately feed by enteral means

Calculations typically based on birth weight for first week of life, then use actual weight thereafter

Must account for: Total fluid volume (mL/kg/day) Total daily caloric requirements (cal/kg/day) Dextrose concentration and glucose infusion rate

(mg/kg/min) Protein (g/kg/day) Lipid (g/kg/day) Electrolytes, trace elements, minerals, vitamins

STARTING POINTS AND ADVANCEMENT:Variable: Starting Point: Advancement: Goal:

Dextrose & Glucose Infusion Rate:

Initial GIR: 6-8

(Usually start D10)

1-2/day depending on glucose levels

Typical max ~14-15

Protein (g/kg/day): 3 0.5-1/day <1500g/32 wks :4

>1500g/32 wks: 3

Lipid (g/kg/day): < 1000g: 0.5

1000-2000g: 1-2

>2000g: 2-3

*Start at 24-30h life

0.5-1/day

1-2/day

1-2/day

3

*Check TG levels prn @ 2-3g

Vitamins: MVI for neonatal/peds

Minerals: “Electrolyte-free” except Ca for first few days

-Start Na at ~2 days-Start K once voiding & serum K<3.5-Ca, Mg, Phos, Cl, Acetate

Trace Elements: Zn, Cu, Mn, Cr, Mo, I

OFF-HOURS TPN FOR PREMIES BW < 1750G:

Goal: Provide protein and calcium within first 24h of life (when can’t order regular TPN yet)

Rationale: ELBW infants lose >1% of protein stores daily, must provide protein to balance loss

Run at 50 mL/kg/day

Components: Dextrose 10% Protein (60 g/L): 3g/kg/day Calcium (4 mEq/L) Minimal electrolytes Heparin

TYPES OF ENTERAL NUTRITION:

Breast milk is the best milk!Lactation counselors can help NBSCU momsDonor breast milk an option for some premies

Variety of formulas available:Term (20 cal): Good Start, Enfamil, SimilacLate Pre-term/Transitional (22cal): Enfacare,

NeosurePre-term (24 cal): Similac Special Care

Supplements to increase calories, etc.:HMF (protein, Ca), Neosure powder, MCT oil

TYPES OF ENTERAL NUTRITION: Specialty formulas available:

Lactose Intolerance/Galactosemia: Soy varieties

Feeding Intolerance: GentleEase, Similac sensitive

Semi-Elemental: Alimentum, Nutramigen, Pregestimil

Elemental: Neocate, ElecareRenal disease: Similac PM 60/40Chylothorax: Enfaport

INITIATION OF ENTERAL FEEDING: Preterm < 1250g:

Goal to start preterm feedings within first 12 hours of life

Start with non-nutritive feeds q4h: Low volume (usually 10-15 mL/kg/day) Acclimate the GI tract to feeds Stimulate gut hormone secretion Promote GI tract maturation

Preterm 1250-1750g: Start within first 12 hours of life with ~20 mL/kg/day

(ie. 4-5 mL/kg/feed q2-3h) Preterm > 1750g or Fullterm:

If stable, start feeds within first 6 hours of life q3-4h May consider ad lib feeds

ADVANCEMENT OF ENTERAL FEEDING:

Goal: Advance slowly to reach full enteral feeds within ~2 weeks of life

Advance daily as tolerated per feeding protocol (~10-20 mL/kg/day for premies)

Monitor for symptoms of intolerance: Abdominal distension Vomiting Bilious aspirates/residuals

ADVANCEMENT OF ENTERAL FEEDING:Feeding Day (Volume – mL/kg/d)

< 0.550g 0.551-0.650g

0.651-0.750g

0.751-0.850g

0.851-0.950g

0.951-1.050g

1.051-1.150g

1.151-1.250g

1

(~12)

1.0 mL q4h

1.2 mL q4h

1.4 mL q4h

1.6 mL q4h

1.8 mL q4h

2.0 mL q4h

2.2 mL q4h

2.4 mL q4h

2

(~24)

2.0 mL q4h

2.4 mL q4h

2.8 mL q4h

3.2 mL q4h

3.6 mL q4h

4.0 mL q4h

4.4 mL q4h

4.8 mL q4h

3

(~36)

1.5 mL q2h

1.8 mL q2h

2.1 mL q2h

2.4 mL q2h

2.7 mL q2h

3.0 mL q2h

3.3 mL q2h

3.6 mL q2h

4

(~48)

2.0 mL q2h

2.4 mL q2h

2.8 mL q2h

3.2 mL q2h

3.6 mL q2h

4.0 mL q2h

4.4 mL q2h

4.8 mL q2h

5

(~60)

2.5 mL q2h

3.0 mL q2h

3.5 mL q2h

4.0 mL q2h

4.5 mL q2h

5.0 mL q2h

5.5 mL q2h

6.0 mL q2h

6

(~72)

3.0 mL q2h

4.0 mL q2h

4.0 mL q2h

5.0 mL q2h

5.0 mL q2h

6.0 mL q2h

6.0 mL q2h

7.0 mL q2h

•After Feeding Day 6: increase 1 mL/feed q24h for 2-3 days and then increase 1 mL/feed q12h until full enteral feeds

•Adapted from Y-NHH NBSCU guidelines

ADVANCEMENT OF ENTERAL FEEDING: As enteral feedings increase, amount of

parenteral feedings decrease Write TPN for NPO rate in case feeds

stoppedDecrease lipid rate accordingly (ie.

Decrease to 50% once at ½ full feeds, etc.)

Fortify feeds with HMF once infant receiving 100 mL/kg/day of human milkFirst fortify to 22 cal then to 24 cal

Consider further increase in calories overtime from to 27 or 30 cal formula +/- MCT depending on growth curves

TRANSITION FROM PG TO PO FEEDING:

Infant must: Weight > 1000 grams and corrected GA > 32 wks Clinically stable with full strength feeds Developmental cues of readiness (suck/swallow)

Advancement: Start with trial of po once daily Then twice daily Then every few/every other feed (PG/PG/PO, PO/PG,

PO/PO/PG) Then all po (PO Ad Lib with minimum, PO Ad Lib)

* Some infants 32-34 weeks might not be ready for all po, consider alternating po/pg feeds

ADDITIONAL NUTRITIONAL CONSIDERATIONS:

Iron fortification: Prevent Fe-deficient anemia Fe supplement given to breast-fed term/pre-term infants Some formula-fed might need if insufficient volume

Vitamin supplementation: Polyvisol for term/pre-term breast-fed infants once full

feeds

Vitamin D supplementation: Term/pre-term breast-fed infants need 400 IU daily Supplement amount depends on feeding method/amount

PREP BOARD REVIEW QUESTION #1:

Item 34 (2011):

A mother in your pediatric practice recently delivered a 28 weeks’ gestation infant who is in the NICU. She exclusively breastfed her previous child who was born at 36 weeks’ gestation. She is concerned that something is wrong with her milk for this infant because it is being combined with HMF. You reassure her that fortification helps to meet the additional needs of her preterm infant.

Of the following, the MOST important role of such fortification is to:

A. augment the immunologic properties of human milk

B. boost the carbohydrate content of human milk

C. decrease the osmolality of human milk

D. enhance the absorption of iron from human milk

E. increase the protein content of human milk

PREP BOARD REVIEW QUESTION #1:

Answer: E. increase the protein content of human milk

Preterm infants need more protein. Preterm 3-4 g/kg/day Term 1.5-2 g/kg/day

HMF provides extra protein to be added to breast milk.

PREP BOARD REVIEW QUESTION #2:Item 226 (2010):

A 30 weeks’ gestation very low-birthweight (VLBW) 1,400-g infant has respiratory distress syndrome (RDS). He is receiving assisted ventilation following administration of 3 doses of surfactant. On his second postnatal day, his mother asks if she can breastfeed her infant. You explain that he will not be able to breastfeed until he is extubated and able to suckle. She asks whether she should pump her breast milk.

Of the following, the BEST response is that expressed human milk feedings:

A. are contraindicated in VLBW infants who have RDS

B. are too difficult for VLBW infants to digest

C. can be fed by NG tube

D. have no net benefit for VLBW infants once frozen

E. have too much protein for VLBW infants

PREP BOARD REVIEW QUESTION #2:

Answer: B. are too difficult for VLBW infants to digest

Breast milk is the best milk! NG feeds can be given when babies cannot

yet tolerate po feeds.

PREP BOARD REVIEW QUESTION #3:Item 50 (2011):

A 27 weeks’ gestation preterm male infant who weighs 900g is delivered at a community hospital by emergent cesarean section. After intubation in the delivery room, he is taken to the nursery for stabilization, including umbilical venous line placement, prior to transfer to a tertiary care center.

Of the following, the MOST appropriate initial solution for parenteral administration would include:

A. 5% dextrose

B. 5% dextrose and 0.2% sodium chloride

C. 10% dextrose

D. 10% dextrose and 0.2% sodium chloride

E. 0.9% sodium chloride

PREP BOARD REVIEW QUESTION #3:

Answer: C. 10% dextrose

Preterm babies are at risk of hypoglycemia and need to have careful blood glucose monitoring.

Initial parenteral fluids typically include 10% dextrose solutions.

Infants do not need sodium administration within the first few days of life.

PREP BOARD REVIEW QUESTION #4:Item 174 (2011):

A 4-month-old male infant presents with abdominal distension, vomiting, and poor weight gain. His temperature is 37.3°C, heart rate is 110 beats/min, respiratory rate is 32 breaths/min, and blood pressure is 96/56 mm Hg. On physical examination, you note abdominal distension, with a palpable mass above the pubic symphysis. Results of laboratory tests include:

Na 136, K 7.2, Cl 110, Bicarb 16, BUN 25, Cr 1.3, Ca 9.5, Mg 1.8, P 5.5

Of the following, the next BEST step in the management of this patient’s electrolyte abnormality is administration of:

A. intravenous calcium gluconate

B. intravenous dextrose and insulin

C. nebulized albuterol

D. oral furosemide

E. oral sodium polystyrene sulfonate

PREP BOARD REVIEW QUESTION #4: Answer: A. intravenous calcium gluconate

All treatment options are correct but first-line approach to decrease K level rapidly is Ca gluconate. (See NBSCU algorithm)

The infant has abdominal distension, FTT, palpable suprapubic mass, hyperkalemia, azotemia, and normal anion gap metabolic acidosis.

Diagnosis is likely obstructive uropathy (posterior urethral valves) with Type IV RTA and hyperkalemia.

References:

Fanaroff and Martin’s Neonatal-Perinatal Medicine: Diseases of the Fetus and Infant

Ambalavanan, N et al. Fluid, Electrolyte, and Nutrition Management of the Newborn. emedicine.com, Last updated June 29, 2010.

Yale-New Haven Hospital NBSCU Guidelines:

- Basic Concepts: Fluid, Electrolyte, and Nutritional Management of Preterm Infants (June 2009)

- Basic Concepts: Total Parenteral Nutrition in the Newborn (June 2009)

- Breastfeeding Initiation and Advancement (April 2006)

- Feeding Intolerance Assessment (April 2006)

- Oral Feedings Initiation and Advancement (April 2006)

- Iron Supplementation (September 2011)

- Vitamin D Supplementation (October 2011)

- Nutrient Contents: Preterm Formulas, Fortified Human Milk Admixtures (June 2008)

PREP Self-Assessment Pediatrics Review and Education Program, AAP, 2009-2011