III. FLUID, ELECTROLYTE & NUTIRTION MANAGEMENT

IN THE NEONATAL ICU

  • Standard IV Fluid Orders
  • Guidelines for Initiation and Advancement of Parenteral Nutrition in the NICU
  • Starter TPN Information
  • TPN Macro/Micronutrient Needs
  • Lab Monitoring Guidelines for Parenteral Nutrition
oEnteral Feeding Guidelines
  • TPN Weaning, Enteral Nutrition Initiation & Advancement
  • Milk/formula Feeding Options
  • Milk & Formula Selection
  • Lab Monitoring Guidelines for Enteral Nutrition
oAssessing Growth in the NICU
  • Nutrition Therapies for Common NICU Disorders
  • Vitamin and Fe Supplementation Guidelines
  • References

STANDARD FLUID ORDERS

(all fluids should be ordered daily)

UAC fluids: ½ NS with 0.25 units of heparin/mL @ 0.8 ml/hr (minimum rate)

*If an infant is hypernatremic, consider changing to D5W with 0.25 units heparin/mL @ 0.8 mL/hr. (Note: it is difficult to obtain accurate glucose measurements from UAC line if D5W infusing).

Peripheral arterial line fluids: ½ NS with 1 unit heparin/mL and 12 mg Papaverine/100 ml at 0.8 mL/hr.

On admission use starter TPN if infant will be NPO more than 24 hours.

  • Starter TPN contains D10W with 3 grams of amino acids/kg and 0.54 mEq/kg of calcium.
  • Run the starter TPN at the patient’s weight in kg x 1.5
  • For example: 500 grams = 0.75 ml/hr
  • Provides a GIR of 2.5 mg/kg/min
  • Piggyback D10W or D12.5W to make up the remainder of the needed fluids.
  • On day of life #2, when TPN is being ordered, remember to discontinue the starter TPN and the piggyback fluids.

Standard pre-op and post-op IVF for infants with normal hydration and electrolyte balance: D10W ¼ NS @ ~100-120 ml/kg/day.

If TPN/maintenance fluids will be running at a rate >2 mL/hr, omit the heparin.

As a general rule, for the first week of life use the infant’s birth weight for all fluid calculations. On day of life #8 begin using the infant’s daily weight. During rounds and sign-outs, specify what weight is being used for calculations.

GUIDELINES FOR INITIATION AND ADVANCEMENT OF PARENTERAL NUTRITION IN THE NICU

Introduction:

Early aggressive nutrition in premature infants has been shown to improve growth outcomes, neurodevelopment and resistance to infection. Timely intervention with TPN begins with the provision of glucose as soon as possible after birth, amino acids within 12 hours and intravenous lipids within 24 hours.

Goal:

  • To minimize the interruption of nutrient delivery and prevent catabolism, especially in premature infants with limited nutritional reserves.
  • Aggressive use of amino acids to prevent “metabolic shock” that would trigger endogenous glucose production and catabolism. Amino acids stimulate insulin secretion to improve glucose tolerance.
  • To attempt to achieve intrauterine growth and nutrient accretion rates in preterm infants.
  • To optimize nutritional status to help both term and preterm infants resist the effects of trauma and disease and improve overall morbidity rates and responses to medical and surgical therapy.
  • To define minimal and maximal acceptable intakes.

This document and the following best practices are based on a review of current literature, recommended evidence-based better practices and recently revised advisable intakes on protein and energy for pre-term and term infants. Please see a list of reviews, studies and references at the end of the document to support the following recommendations.

STARTER TPN

Rationale: Newborn infants who do not receive protein have negative nitrogen balance and lose up to 1% of their protein stores daily. Catabolism is a particular problem of the very low birth weight infant who may have minimal nutritional reserves. Additionally, recent studies have indicated that when there is a shortage of amino acids, insulin levels fall, resulting in hyperglycemia and hyperkalemia. Parenteral intakes of 1.5 grams/kg/day of protein appear to be sufficient to prevent catabolism in newborn infants, and to maintain normal serum glucose and potassium levels.

Target Patient:

Newly admitted patients <1500 grams

Newly admitted patients 1500-1800 grams who are NPO for 24 hours

Term infants NPO >1-2 days or complex surgical patients.

Recipe:

Central & Peripheral Lines: D10W (Dextrose 10g/100mL) + 8.25 g/100mL Neonatal amino acids + 1.5 mEq/100mL Calcium Gluconate

Procedure:

Run @ 1.5 mL/kg/hour

For example: Birth weight of 500 grams = run at 0.75 ml/hr

This volume provides 36 ml/kg/day of fluid, a GIR of 2.5 mg/kg/min, 3 g/kg/day of protein and 0.54 mEq/kg/day calcium

Order Writing for Starter TPN:

  • On admission, 7 days a week, 24 hours per day for target patients
  • A TPN order is not needed
  • Check glucose 4 hours after starting
  • Another maintenance fluid will always need to be ordered to maintain an adequate glucose infusion rate and fluid intake
  • Start regular TPN the next scheduled interval and order 3 – 3.5 grams of amino acids per kg per day (2.5-3 g/kg/day for term infants).
  • Do not discontinue the starter TPN if the baby is hyperglycemic or hyperkalemic as it may make the situation worse. Consider changing the piggyback maintenance fluids to decrease the dextrose delivery.
  • You cannot adjust the contents of Starter TPN

TPN Macronutrients:

Initiation and Advancement Guidelines

Initiation / Advancement / Goal
Premature Infant < 32 weeks, < 1000 grams / Dextrose (GIR) / 4 – 6 mg/kg/min / 1 – 2 mg/kg/min / ≤ 12 mg/kg/min c
Amino Acids / 3 – 3.5 g/kg/d e / 0.5 - 1g/kg/d / 4 g/kg/d
Lipids / 1 g/kg/d / 0.5 - 1g/kg/d / 3-3.5 g/kg/d d
a Non-Protein Calories / 40 -50 kcals/kg/d b / 60 – 70 kcals/kg/d / 85 – 95 kcals/kg/d
Total Calories / 50 – 60 kcals/kg/d / 70 – 80 kcals/kg/d / 90-100 kcals/kg/d
Premature Infant < 32 – 36 weeks, > 1000 grams DOL: 0 / Dextrose / 4 – 6 mg/kg/min / 1 – 2 mg/kg/min / ≤ 12 mg/kg/min c
Amino Acids / 3 – 3.5 g/kg/d e / 3.5 g/kg/d
Lipids / 1 g/kg/d / 0.5 - 1g/kg/d / 3 g/kg/d d
a Non-Protein Calories / 40 -50 kcals/kg/d b / 60 – 70 kcals/kg/d / 85 – 95 kcals/kg/d
Total Calories / 50 – 60 kcals/kg/d / 70 – 80 kcals/kg/d / 90-100 kcals/kg/d
Term Infant, > 37 weeks / Dextrose / 6 – 8 mg/kg/min / 2 – 3 mg/kg/min / ≤ 12 mg/kg/min c
Amino Acids / 2 – 3 g/kg/d e / 0.5 - 1g/kg/d / 2.5 – 3 g/kg/d
Lipids / 2 g/kg/d / 0.5 - 1g/kg/d / 2.5 – 3 g/kg/d d
a Non-Protein Calories / 40 – 50 kcals/kg/d b / 50 – 60 kcals/kg/d / 70 – 80 kcals/kg/d
Total Calories / 50 – 60 kcals/kg/d / 60 – 70 kcals/kg/d / 80 – 90 kcals/kg/d

a Goal is to supply ~25 calories per gram of protein. Use a combination of glucose and lipid as the energy source. Non-protein calories are used to calculate energy needs in the NICU. Feeding summaries do not include protein calories from TPN.

b Minimum calorie and amino acid intake for “zero balance” (i.e. not catabolic) can be achieved with 40 - 50 kcals/kg/day (basal metabolic energy needs) and 1.5 g/kg/d protein. Note: a GIR of 6 - 8 mg/kg/min with 1 g/kg lipids will provide ~40 - 50 non-protein kcal/k/d in ELBW infants.

c Do not exceed the maximal oxidative glucose capacity of 12.5 mg/kg/min or 18 g/kg/d of carbohydrate (for cholestatic jaundice keep around 15 g/kg/d of carbohydrate).

Usual maximum concentration: 12.5% peripheral route, 25% central route.

d Fluid restricted (≤150 ml/kg/d), growth compromised patients limited by peripheral access may require lipid infusion as high as 4 g/kg/d. However, this should not routinely be the end goal of intravenous lipids.

*To prevent essential fatty acid deficiency, provide a minimum of 0.5 g/kg/d of intravenous lipids.

e There is no evidence that gradually increasing amino acid intake improves “tolerance” to amino acids. Order 3 – 3.5 g/kg/d amino acids with the first regular TPN following starter TPN.

f Use starter TPN for term infants made NPO for >1-2 days or complex surgical patients

TPN Guidelines: Micronutrients, etc.

  • Order TPN daily by 14:00 to ensure delivery by 20:00
  • Determine total daily fluids and subtract out other IV fluids, supplemental enteral nutrition and IV fat emulsion volume to determine TPN fluid volume.
  • Cycled TPN should be tapered unless a dextrose solution is running while the TPN is off. Consider checking a serum glucose concentration 1 hour after the TPN is off to ensure cycled TPN rate is tolerated.

Macronutrients (Protein, Dextrose and Lipids)

Dextrose:Maximum concentration peripherally = 12%; Central 25%

Maintain glucose infusion rate (GIR) 12 mg/kg/min for optimal glucose utilization

GIR (mg/kg/min) = (% dextrose X rate in mL/hr ÷ 6 ÷ (wt in kg))

Protein:Begin with 3 g/kg/day and advance to goal of 3.5-4 g/kg/day

Never begin with < 3g/kg/day since this is the amount delivered in Starter TPN

Lipids:0.5-1 g/kg/day is needed to prevent essential fatty acid deficiency (can develop within 72 hours after birth)

Advance lipids by 0.5-1 g/kg/day to maximum of 3-3.5 g/kg/day

Consider serum triglyceride level if infused greater than 0.15 g/kg/hr (0.75 mL/kg/hr), or if the patient is septic

Consider decreasing lipids if serum triglyceride is greater than 200 mg/dL or Direct Bili is > 2 mg/dL

Calcium & Phosphorus

● Ideal ratio of Calcium (mEq): Phosphorus (mMol) is 2-2.5:1 for best absorption of both nutrients

● Mineral wasting can be caused by a Ca:Phos ratio less than 1.6 mEq:1 mmol

● Always attempt to maximize these nutrients for premature infants if able

Goal: 3 mEq/kg/day Calcium and 1.5 mmol/kg/day Phosphorus (MAX= 4mEq/kg Calcium & 2 mmol/kg Phos)

● If unable to reach goals due to precipitation, consider the addition of cysteine to the TPN solution to increase the solubility

Phosphorus is given as NaPhos or KPhos- you will not be able to meet phosphorus goal if there are insufficient amounts of these nutrients in the TPN

Electrolytes, Vitamins, Minerals & Trace Elements

Sodium/Potassium: Adjust amounts in TPN based on lab values
Magnesium: Consider exogenous maternal tocolytic as a source in the initial days of TPN
Magnesium depletion may precipitate refractory hypokalemia and hypocalcemia
Standard Multivitamins: 2 mL/kg/day (maximum dose of 5 mL/day) of Pediatric MVI
Pediatric MVI contains 40 mcg/mL of Vitamin K
If Vitamin K is ordered, it will be in addition to the standard multivitamin dose
Standard Trace Elements (in 0.2mL/kg):
Pediatric / < 3 kg / 3-6 kg
20 mcg/kg Copper / 20 mcg/kg Copper / 20 mcg/kg Copper
6 mcg/kg Manganese / 1 mcg/kg Manganese / 1 mcg/kg Manganese
0.2 mcg/kg Chromium / 0.2 mcg/kg Chromium / 0.2 mcg/kg Chromium
100 mcg/kg Zinc / 400 mcg/kg Zinc / 250 mcg/kg Zinc
Omit the manganese and chromium in TPN solutions if an infant has severe hepatic disease (e.g. Direct Bili >2mg/dL) or is on long-term TPN Continue to provide standard copper for these patients and monitor blood concentrations if there is a concern for toxicity
Consider a decreased dose or elimination of chromium and selenium (see below) with severe renal disease
Consider extra Zinc if increased ostomy output, diarrhea or significant NG suction

Other Additives:

Cysteine: If unable to meet calcium and phosphorus goals due to precipitation in the TPN, consider adding 30 mg of . cysteine per gram of protein in the TPN. This reduces the pH and increases the solubility of calcium/phos.

Monitor acid/base balance if added.

Carnitine: For optimal lipid utilization, consider adding 5-10 mg/kg/day in patients on TPN greater than 2-4 weeks.

Do not add until lipids are initiated. Discontinue when lipids are not given.

Iron Dextran: Only consider in patients greater than 2 months of age on chronic TPN and unable to provide enteral iron

Selenium: Consider in patients maintained on TPN for 1 month or with severe GI issues. Do not give selenium if N

creatinine level is >1. Normal dose = 1.5-4.5 mcg/kg/day; max 30 mcg/day.

LAB MONITORING GUIDELINES FOR PARENTERAL NUTRITION IN THE NICU

< 1 week of TPN / >1 week of TPN
and clinically stable
Electrolytes** / Daily / 2x/week
Ca, Mg, Phos / 2x/week / 1x/week
Glucose / Daily / Every other day
BUN/Cr / Daily-2x/week / 1-2x/week
Bilirubin (T/D) / 2x/week / 1x/week
Triglycerides / As lipids advance / 1x/week
Prealbumin / ---- / Every other week if unable to maximize protein in TPN
Alk Phos / ---- / Every other week if inadequate calcium/phos in TPN
AST/ALT / ---- / 1x/month
  • This assumes that TPN remains relatively unchanged the first week. With changes, some labs may need to be checked more frequently. Labs may also need to be checked more frequently for ELBW or clinically unstable infants.
  • Serum electrolytes should be monitored at least daily on infants whose IV fluid intake exceeds 40% of total intake.
  • Magnesium may need to be checked in high risk infants with chronic gastrointestinal losses and infants born to mothers on high dose Magnesium Sulfate to suppress labor.

Rationale for monitoring patient groups on parenteral nutrition:

  • Electrolyte abnormalities are the most common metabolic complication in infants on IV fluids.
  • Premature infants are at risk for hyper and hyponatremia when establishing baseline fluid and electrolyte needs.
  • Indirect bilirubin is used to determine need for phototherapy and/or exchange transfusions.
  • Hyperkalemia is frequent in VLBW infants.
  • BUN and creatinine help to evaluate renal function, hydration and protein status.
  • Micropreemies (birth weights <700 grams) and IUGR infants are at increased risk for altered electrolytes.
  • Infants receiving parenteral nutrition for >2 weeks are at risk for cholestatic jaundice.
  • Infants receiving parenteral nutrition for >2 weeks are at risk for developing metabolic bone disease.

ENTERAL NUTRITION GUIDELINES

Enteral nutrition is the preferred method of nutrient delivery for all infants in the NICU. The goal is to initiate enteral feeds within a few days of birth. These feeds, known as trophic feeds or minimal enteral nutrition, will continue for a few days before advancing to aid in GI priming and help avoid feeding intolerance and necrotizing enterocolitis. For premature infants, hemodynamic instability often times delays these feeds, and parenteral nutrition must be initiated first and continued as a supplement until full enteral feedings can be tolerated.*See the following page for TPN weaning and enteral nutrition initiation and advancement guidelines

The majority of nutrient storage occurs in the third trimester, especially fat and glycogen stores, iron reserves and calcium and phosphorus deposits. The goal of enteral nutrition in the NICU is to attempt to achieve nutrient accretion rates similar to those infants would receive in utero.

While breast milk is the preferred feeding for all infants in the NICU, it lacks sufficient amounts of vital nutrients that premature infants need for adequate growth and development. Human milk fortifier (HMF) is added to breast milk to increase the overall energy, protein, calcium, phosphorus and electrolyte content. Premature formulas are also available for premature infants when breast milk is not available and contains similar nutrient profiles to that of fortified breast milk.

Contraindications to starting enteral feeds:

  • Any condition associated with decreased gut blood flow
  • Asphyxia, hypoxemia, hypotension, concomitant use of indomethacin/ibuprofen
  • Diastolic intestinal blood flow “steal” secondary to a PDA
  • Sepsis and/or significant clinical instability
  • High pressor support

Benefits of Trophic Feeds:

  • Stimulates GI tract, promotes GI maturation and improves GI motility
  • Reduces intestinal permeability
  • Faster transition to full enteral feeds (less TPN)
  • Improved mineral absorption and glucose tolerance

Route:

  • NG or OG, usually through a soft, indwelling tube.
  • Breast/bottle attempts may begin once the infant is showing active feeding cues, which develop around 33-34 weeks.

Enteral Nutrient Requirements

Preterm / Term
Energy (kcal/kg/day) / 120-130 / 100-110
Protein (g/kg/day) / 3.5-4.5 / 2-3
Calcium / 100-220 mg/kg/day / 210 mg/day
Phosphorus / 60-140 mg/kg/day / 100 mg/day
Iron (mg/kg/day) / 2-4 / None needed if iron-containing solids are introduced at 4-6 months of age

TPN Weaning Schedule

For VLBW Infants

Enteral Feeding Volume

(mL/kg/day) / NPO / 20 / 40 / 60 / 80
** / 100
** / 120 / 140
Concentration of
Breast Milk/Formula
(kcal/oz) / 20 / 20 / 20 / 20/24 / 20/24 / 24 / 24
TPN GIR* (mg/kg/min) / 6-12 / 6-12 / 6-12 / 6-10 / 6-8 / 6-8 / TPN is typically D/C’d once infants are @ 120 ml/kg/day. Use IVFs to meet fluid needs.
Do not give Starter TPN if feeds are fortified- this leads to excessive protein intake.
TPN Protein (g/kg) / 3.5-4 / 3.5 / 3.5 / 3 / 2.5 / 2.5/2
TPN Lipids (g/kg) / 3-3.5 / 3 / 3 / 2.5 / 2 / 1.5
TPN Calcium/Phos
(mEq/mmol) / 3/1.5 / 3/1.5 / 3/1.5 / 2.5/1.3 / 2/1 / 2/1
TPN Total kcals/kg/day / 90-100 / 90-100 / 70 / 65 / 50/40 / 40/25

*GIR will vary based on glucose levels. The GIR should be adjusted as needed to meet overall energy goals of 90-100 kcal/kg/day (TPN only) & 100-110 kcal/kg/day (TPN + enteral feeds)

**Fortify feeds to 24 kcal/oz. once the infant is tolerating 80-100 ml/kg/day enterally

Enteral Nutrition Feeding Initiation & Advancement

Birth Weight (g) / Initiation Rate (ml/kg/day)
*Continue for
3-5 days / Frequency / Advancement Rate* (mL/kg/day) / Goal Volume (ml/kg/day) / Type of Feeding
<750 / 10-20 / Q2H or less / 20 / 150 / Breast milk**
751-1250 / 20 / Q2H / 20 / 150 / Breast Milk**
1251-1500 / 20-30 / Q3H / 20-40 / 150 / Breast Milk**
1501-2000 / 20-40 / Q3H / 20-40 / 150 / MBM or Preterm Formula
2001-2500 / 30-50 or ad lib with cues / Q3H / 30-50 / 150-180 / MBM or Transitional formula (Neosure/Enfacare)
>2500 / 50 or ad lib with cues / Q3H if scheduled / 50 / 180 / MBM or Term Formula

*Advancement rates will vary based on tolerance.

** Breast milk, either Mother’s own or donor milk (with consent), should be the first feeding for all infants born <1500 grams. Preterm formula would only be given to these infants if the mother refuses to provide her own milk and does not consent to the use of donor milk.

MILK/FORMULA OPTIONS IN THE NICU

Breast milk should be the first feeding for all infants in the NICU, unless contraindicated due to medication use or infections.

Contraindiations to using breast milk:

  • Infants with galactosemia or some inborn errors of protein metabolism
  • Mothers with herpes simplex lesions on the breast; with active, untreated tuberculosis, or who are HIV-positive
  • Mothers receiving radioactive isotopes, chemotherapeutic agents, and certain medications
  • Mothers using drugs of abuse

Donor Breast Milk

  • Donor breast milk (DBM) is available for all infants born <1500 grams and <34 weeks in our NICU. The goal is to avoid the use of formula in these infants. DBM allows us to start enteric feeds as soon as the infant is medically ready, even if the mother’s milk has not come in. It can also be used to supplement feeds if a mother has a low milk supply.
  • DBM is continued until the infant reaches 34 weeks and 1500 grams. At this time, the infant would transition to a premature formula.
  • Consent must be obtained before administering DBM.

Human Milk Fortifiers: Used to fortify breast milk for infants born <2kg & <35weeks

  • Similac HMF & Enfamil HMF (contain bovine proteins)
  • Prolacta
  • This is the only human milk-based HMF. Infants with a birth weight <1250 grams qualify for the use of Prolacta only after 2 failed attempts at the use of powdered HMF. Never order Prolacta without a discussion with the MD and dietitian.

Premature Formula: For infants born <2kg & <35 weeks if the mother does not provide her own milk or does not consent to the use of donor milk if the infant is <1500g and/or <34 weeks

  • Similac Special Care (SCF): 20 kcal/oz, 24 kcal/oz. High Protein & 30 kcal/oz.
  • Enfamil Premature Formula: 24 kcal/oz.

Transitional Formula: Used at discharge or for late-preterm infants

  • Neosure & Enfacare
  • These formulas have a nutrient profile that is between premature formula and term formula. When made as directed on the can, it will make 22 kcal/oz. formula and provide higher amounts of protein, calcium and phosphorus.

Term Formula: For infants >36weeks and >2500g when breast milk is not available