Fluid , electrolyte and nutritional requirements for

neonates

Presented by : Maram Mobara

FEN Management in Neonates

One of the essentials of neonatal care

Many babies in NICU need IV fluids

They all don’t need the same IV fluids (either in quantity or composition)

• the body is composed mainly of water

• body water in early embryo represent 97% of body weight

• premature infants body water represent 80-90% of their weight

• newborn infant 77%

• adult 60%

Things to consider: Normal changes in TBW, ECF

So, All babies are born with an excess of TBW, mainly ECF, which needs to be removed

ECF in infant is 40%of body weightin adult 20%

as the child grows,, there is muscle growth and cellular growth ,, more water shifts from ECF to ICF compartment

infant has less reserve of body fluid ,, more likely to develop fluid volume deficits

the infant needs more water due to ;1.large body surface area2.immature kidneys which cannot

concentrate urine effectively high UOP

Things to consider: Insensible water loss (IWL)

“Insensible” water loss is water loss that is not obvious through skin (2/3) or

respiratory tract(1/3)• depends on gestational age (more preterm: more IWL)• depends on postnatal age (skin thickens with age: older is better --> less IWL)• also consider losses of other fluids: Stool (diarrhea/ostomy), NG/OG drainage, CSF (ventricular drainage), etc

Management of F&EManagement of F&E

Goal:Goal: Allow Allow initial loss of ECFinitial loss of ECF over first over first week week (as reflected by wt loss),(as reflected by wt loss), while while maintaining normal maintaining normal intravascular intravascular volume and tonicity (as reflected by volume and tonicity (as reflected by HR, UOP, lytes, pH).HR, UOP, lytes, pH).

Subsequently, maintain water and Subsequently, maintain water and electrolyte balance, including electrolyte balance, including requirements for body growth.requirements for body growth.

Individualize approachIndividualize approach

TFI = Maintenance requirements (IWL+Urine+Stool water) + growth

In the first few days, IWL is the largest component

Urine: 60 cc/kg/dayStool: 5-10 cc/kg/dayGrowth: 20-25 cc/kg/day (since wt gain is 70% water)

Management of F&E (contd.)Management of F&E (contd.)

Guidelines for fluid and electrolyte therapyGuidelines for fluid and electrolyte therapy

Fluid rate ml/kg/d

electrolyte meq/kg/d

Term infant 1st day 2nd &3rd 4th

Dextrose10% 60-80 +10-20 +20

Sodium - 2-4* 2-4*

Potassium - 1-2 * 2-4*

60-80ml/kg/day will provide 6-7 mg/kg/min of glucose

Factors modifying fluid requirement:

•Maturity --> Mature skin --> reduces IWL•Elevated temperature (body/environment)--> increases IWL•Humidity: Higher humidity --> decreases IWL up to 30% (over skin and over respiratory mucosa)•Skin breakdown, skin defects (e.g. omphalocele)--> increases IWL (proportional to area)

•Radiant warmer --> increases IWL by 50% •Plastic Heat Shield --> reduces IWL by 10-30%•Phototherapy --> increases IWL by 50%

Monitoring of fluid and electrolyte status;should be done daily for

1.body weight; loss >20%of birth weight during first week of life = uncompensated IWL , < 2% for first 4-5 days = excessive fluid administration

2.serum level of ; hematocrit, Na+,K+, BUN, creatinine, osmolarity, acidosis and base deficit,, if increased may indicate inadequate fluid tx

3.fluid input, output; UOP <1ml/kg/hr may indicate need to increase fluid intake,,, >3ml/kg/hr may indicate overhydration

4.general appearance and vital signs; hypotension, poor perfusion, poor pulses all are signs of inadequate fluid intake

Common electrolyte problems :

Sodium:

Hyponatremia (<127mEq/L)Hypernatremia (>145 mEq/L)

Potassium:

Hypokalemia (<3.5 mEq/dL)Hyperkalemia (> 5.5 mEq/dl)

Calcium:Hypocalcemia (total<7 mg/dL; i<4)

Hypercalcemia (total>11mg/dL; i>5)

Hyponatremia : < 127mEq/lHyponatremia : < 127mEq/l

Sodium levels often reflect fluid status rather than sodium intake

ECF Excess Excess I VF, CHF, Sepsis, Paralysis

Restrict fluids

ECF Normal Excess I VF, SI ADH, Pain, Opiates

Restrict fluids

ECF Deficit Diuretics, NEC (third spacing)

I ncrease sodium intake

Management :

If baby have seizure:

Emergency

1. hypertonic saline solution (3% sodium chloride )

2.Calculate deficit , give half over 12-24 hour

3.Rapid correction result in brain damage

If due to volume over load : fluid restriction, decrease maintenance by 20 ml/kg/d

If due to inadequate sodium intake:

• check formula

1.equation: desired level – (sodium value*weight*0.6(

2.Give for 12-24 hour

Hypernatremia: > 145 mEq/l

•Hypernatremia is usually due to excessive IWL in first few days in VLBW

infants

•Increase fluid intake and decrease IWL.

•Rarely due to excessive hypertonic fluids

•Decrease sodium intake

•Potassium is mostly intracellular: blood levels do not usually indicate total-body potassium

• pH affects K+: 0.1 pH change=>0.3-0.6 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

PotassiumPotassium

Hypokalemia : < 3.5 mEq/dl

arrhythmia ( Diuretics / digitalis ?)

how much receiving by maintenance ?

Diarrhea ? NGT tube output ?

Ileus Repeat measurement

Renal K+ ( Barrter’s syndrome)Blood gas level

X-rayECG

Tx the cause , slow correction over 24 hr , decrease dose once reach high normal level

Hyperkalemia: > 5.5 mEq/dl

•How was the specimen collected ?

•How much is infant receiving ?

•ECG changes ?

•BUN & creatinine ? UOP?

•Blood gases ? Acidosis cause k+ to move out of the cell

•Tissue necrosis ,NEC (x-ray)

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)

kayexalate, potassium exchange resin 1g/kg/dose po/rectally (slow action)

Dialysis/ Exchange transfusion

Metabolic alkalosis caused by electrolyte loss, specifically chloride,

occur with prolonged gastric suction or vomiting and is easily corrected by

replacement of the appropriate electrolyte

So look for electrolyte loss espcially chloride and potassium and correct deficiet

If due to prolonged suction , IV fluid transfusion with ½ normal saline + 20 meq kcl

Metabolic acidosis is usually the result of poor tissue perfusion and lactic

acidosis. treat the underlying cause of the poor perfusion and by temporarily administering buffers, such as sodium

bicarbonate, which is usually done when the pH falls below 7.3. use this formula

to give the dose:NaHCO3 (mmol) = base excess x body

weight (kg)/3

Hypocalcemia: total<7 mg/dL; i<4

Normal physiology:

3rd trimester Ca from mother

1-2 days of life drop to 7.5 (loss of source, calcitonin)

3rd day normal ca level (gradual increase in PTH)

In ECF has 3 forms : bound to albumin / anions

ionized 50% : impo. for coagulation, enzymes, cell membrane, neuromuscular excitability

Clinically

( DOESN’T correlate with severity)• no symptoms• Lethargy, Poor feeding, Vomiting, Abdominal distension• Cyanosis, stridor• Seizures• Apnea• Tetany and signs of nerve irritability, Chvostek sign, carpopedal spasm, Trousseau sign• Prematurity, birth asphyxia• ECG, prolonged QTc (>0.4 s), a prolonged ST segment, and T wave abnormalities may be observed

Causes of hypocalcemiaCauses of hypocalcemia

Early neonatal hypocalcemia (48-72 h)

•Prematurity:. •Birth asphyxia: renal insuff. ,

metabolic acidosis,decreased PTH •Diabetes mellitus in the mother :

increased req. by macrosomic baby

Late neonatal hypocalcemia (3-7 d)

•Exogenous phosphate load: feeding with phosphate-rich

formula or cow's milk. •Magnesium deficiency

•Transient hypoparathyroidism of newborn

•Hypoparathyroidism due to other causes

Management

•Screen high risk group (4 mg/kg/d of 10% calcium gluconate)

•symptomatic patient :Bolus Calcium gluconate (10% solution) is given IV at 1-2 ml/kg (100 mg/kg) slowly . Maintenance therapy is given at 200 mg/kg/day IV and increased as needed to maintain serum calcium level

at 7 to 8 mg/dl.

•Should be diluted with 5% dextrose, under cardiac monitor ( bradyarrhythmia) in NICU

•Look for the cause :•Mg :HypoCa may not respond to calcium therapy if

hypoMg is not corrected (by 0.2ml/kg of 50 % solution )

•low serum albumin concentration and abnormal pH •Serum electrolytes and glucose (exclude)

•Phosphorus•PTH

HYPOGLYCEMIA

Blood sugar level < 40mg/dl ----- 2.2mmol

Send for lab result

Is infant symptomatic? apnea, hypotonic, cyanosis, seizures, lethargy, temp. instability

How much is infant receiving? Normal requirement 6mg/kg/hr

Possible causes:

Premature ( decrease glycogen stores), IUGR

Diabetic mother( b cell hyperplasia), Beckwith W. syndrome, tumors

Sepsis

Hypothermia

Asphyxia

Endocrine disorders

Plan

Maintain NORMOglycemia

Send for baseline glucose level

Asymptomatic w glucocheck < 25 mg/dl

IV access

Give glucose 6mg/kg/hr

Check every 30 min

Increase gradually until NORMO

Bolus # in asymptomatic (rebound hyper)

Glucocheck 20-40mg/dl

Feeding w D5W

Check every 30 min

If stays low start infusion 6mg/kg/hr

Symptomatic patient :

Baseline serum level

Infusion of2-4 ml/kg of 10% glucose solution over 2-3min

Continuous infusion at rate of 6-8ml/kg/min

Check every 30 min

Until 40 mg/dl serum glucose level

Maintain normoglycemia

Goals: Normal growth and development

Nutrient requirements: Energy Carbohydrate Water Minerals Protein Vitamins Fat Trace elements

Nutritional requirements in the neonates :

Calories : 50-60 kcal/kg/day to maintain weight

100-120 kcal/kg/day to gain weight

Carbohydrates: 11-15g/kg/d (40-50% of total calories)

Proteins: 2.25-4 g/kg/d (7-15% of total calories)

Fats: 4-6g/kg/d (< 50% of total calories)

Vitamins: requirements are not clearly established. Vitamin supplementation depends on the formula needed.

Energy needs:

depend upon age, weight, maturation, caloric intake, growth rate, activity, thermal environment, and nature of feeds.

•Stressed and sick infants need more energy (e.g. sepsis, surgery)

• Parenteral nutrition need less energy (less fecal loss of nutrients, no loss for absorption): 70-90 Cal/kg/day + 2.4-2.8 g/kg/day Protein adequate for growth

•Count non-protein calories only! Protein to be preferred used for growth, not

energy•65% from carbohydrates, 35% from

lipids ideal

How to be organized ?

To calculate a neonate’s F,E,& N:First calculate the amount of fluid (Water)

plan how to give it: Parenteral (IV) or Enteral (OG/PO)

calculate the amount of energy required

Decide how to provide the energy: amount and nature of carbohydrates and lipids

Provide proteins, vitamins, trace elements

Carbohydrate

IV: Dextrose 3.4 Cal/g = 34 Cal/100 cc of D10W.

Tiny babies are less able to tolerate dextrose.

If blood levels >150-180 mg/dL, glucosuria=> osmotic diuresis, dehydration

Insulin can control hyperglycemia

Hyper- or hypo-glycemia => early sign of sepsis

Avoid Dextrose>12.5% through peripheral IV

Carbohydrate (cont.)

Enteral: Human milk 20 Cal/oz formula = 67 Cal/100 cc

Lactose is carbohydrate in human milk and term formula.

Soy and lactose free formula have sucrose, maltodextrins and glucose polymers

Preterm formula has 50% lactose and 50% glucose polymers (lactase level lower in premies, but glycosidases active)

FatParenteral:

20% Intralipid (made from Soybean) better than 10%

High caloric density

Start low, go slow (0.5-3 g/kg/day)

Avoid higher amounts in sepsis, jaundice, severe lung disease

Maintain triglyceride levels of < 150 mg/dL. Decrease infusion if >200-300 mg/dL

Fat (cont.)

Enteral:Approximately 50% of the calories are derived from fat. >60% may lead to ketosis.

Medium-chain triglycerides (MCT) are absorbed directly. Preterm formula have more MCT for this reason.

At least 3% of the total energy should be supplied as EFA

Proteins: 2.25-4 g/kg/d (7-15% of total calories)

Restrict in stressed infants or infants with cholestasis to 1.5 g/kg/day Very high protein intakes (>5-6 g/kg/day) may be dangerous

Minerals (other than Na,K, Cl)

Calcium & Phosphorus:Third trimester Ca accretion (120-150mg/kg/day) and PO4 (75-85 mg/kg/day) is more than available in human milk. Hence, HMF is essential. Premie formula has sufficient Ca/PO4.

Magnesium: sufficient in human milk & formula

Iron: Feed Fe-fortified formula. Start Fe in breast feed infants at 4 months of age, and in premies once full feeds are reached.

Vitamins

Fat soluble vitamins: A, D, E, K

Water soluble vitamins: Vitamins B1,B2, B6, B12, Biotin, Niacin, Pantothenate, Folic acid, Vitamin C

All neonates should get vit K at birth

Term neonates: No vitamin supplement required, except perhaps vit D

Preterm: Start vitamin supplements once full feeds established if on human milk without HMF. No need if on human milk with HMF, or preterm infant formula.

Trace elements

Zinc, Copper, Selenium, Chromium, manganese, Molybdenum, Iodine

Most preterm formulas contain sufficient amounts

Fluoride supplementation not required in neonatal period

Postoperative Feeding : Neonates have most difficulty in feeding

the work of feeding accounts for most of a neonate caloric expenditure, and a stressed neonate tires easily

For this reason, gavage or gastrostomy tube feedings are generally employed for the early stages of postoperative feeding in neonates.

evidence that the bowel is beginning to function is the disappearance of the bilious green color of the gastric aspirate and the decrease in the volume of the aspirate from the nasogastric or gastrostomy tube.

Important points to consider

Cont.

Always start with small volumes of rehydration fluid.

If these are tolerated, the feedings are increased gradually until the nutritional goals for the patient have been reached.

Infants tolerate increases in volume more than increases in osmolarity. Accordingly, it is often best to start with diluted formulas (three-quarter-strength, half-strength, or quarter-strength

In infants, whenever possible, oral feedings or oral stimulation should accompany tube feedings.

Abdominal Wall Defects

The exposure of bowel results in greater insensible loss of fluid and heat

It is crucial to place children with gastroschisis in a warm environment and to protect the bowel (by the help of a plastic bowel bag).

Intravenous access should be established immediately, and resuscitation should be initiated before any surgical intervention

I.V. line should be placed in the upper extremities or the neck

Surgical cases associated with F,E&N problems

Intestinal Obstruction

These patients usually present with choking or vomiting

They may show signs of severe dehydration with metabolic alkalosis (hypochloremic, hypokalemic )

the maintenance requirements and third-space losses ,can be replaced with 5% dextrose in 0.25 normal saline with supplemental potassium chloride at 3 mEq/kg/24 hr.

Consider TPN

Surgical cases associated with F,E&N problems

Diaphragmatic Hernia

acute respiratory distress and hemodynamic instability

Babies will require immediate resuscitation, correction of acidosis, and, in most cases, endotracheal intubation.

Surgical cases associated with F,E&N problems

Thank you

References •Neonatology a Lange clinical manual,3rd edition,Gomella T. et.al,Appleton& Lange.

•Neonatology pathophysiology and management of the newborn, 5th ed,Gordon B.et.al.Lippincott Williams & Wilkins.

•Arnold G. Coran, M.D., F.A.C.S., Professor, Division of Pediatric Surgery, Department of Surgery, University of Michigan Medical School, Surgeon-in-Chief, Section of Pediatric Surgery Department of Surgery, C. S. Mott Children's Hospital,ACS Surgery.  2000; ©2000 WebMD Inc.