1. Nutrition in the Neonate

2. Importance of Nutrition in Early Life
Critical periods in fetal and neonatal life which may result in long lasting effects in adulthood
Examples:
Inverse relationship between Birth weight and mortality from coronary artery disease as adult. Infants < 5.5lbs have 2x risk of cardiac mortality & hypertension vs 8-9lb. Infants >9lb increased cardiovascular risk and obesity.
Breast feeding resulting in lower cholesterol levels and lower systolic blood pressure, and protective against childhood obesity

3. Gastrointestinal Tract in Premature Infant
Intestinal tract elongates 1000x during 5-40 weeks gestation- doubles in length during last 15 weeks to 275 cms at birth.
Fetal swallowing: 450ml/day in 3rd trimester. Fluid includes growth factors. Availability interrupted by premature birth
Gastro-esophageal tone is decreased
Motility is delayed

4. Nutrition Requirements
Growth rate after birth is much slower than in-utero
Undernourished at a vulnerable time
Protein and energy must be provided in appropriate proportion for optimal utilization of each
Nutrient intakes must meet needs for deposition and replacement of ongoing losses
Protein is continuously lost via skin as desquamated cells and as urea
Resting metabolic rate is increased with prematurity, disease states, and low birth weight

5. Neonatal Energy Form of Energy Caloric Expenditure
Resting Metabolic Rate* kcal/kg/day
Activity kcal/kg/day
Cold Stress kcal/kg/day
Nutrition Processing 50 kcal/kg/day
Total kcal/kg/day
Processing indicates excretion, storage, and synthesis.
Resting metabolic rate is increased with prematurity, disease states, and low birth weight
Most sources recommend caloric requirement of kcal/kg/day to balance energy expenditure
Assumption is that postnatal growth should mirror in utero growth of a fetus at the same postconceptual age
Activity accounts for only 10% since infants sleep 80-90% of the time but this can increase with agitation
Ideally the preterm infant should grow the same as the fetus in utero g/kg/day

6. Nutrition Requirements- Carbohydrates
Primary energy substrate for brain metabolism
Hepatic glycogen content is limited
Gluconeogenesis (production of glucose from amino acids and lipid oxidation) is large contributor to glucose production
Glucose regulatory hormones and enzymes are not fully developed
Increased risk for hypoglycemia
Hyperglycemia: exceeding normal glucose turnover rates; stress; relative insulin deficiency; hepatic peripheral insulin resistance
Very preterm infants have poor glycogen stores and decreased substrates for gluconeogenesis, thus are vulnerable to developing hypoglycemia

7. Nutrition Requirements- Lipids
Source of essential Fatty Acids and LCPUFA
Linoleic and linolenic acid comprise cell membranes
LC-PUFA (AA & DHA) important for brain and retinal development
Energy substrate readily utilized by VLBW
Decreases amino acid oxidation and protein breakdown when lipid provides 50% of non-protein calories
Provides greater energy and is isotonic compared to high concentration dextrose
AA: arachidonic acid
DHA: docosahexaenoic acid

8. Benefits of Early Parenteral Nutriton
Provides nutritional support and supplements enteral feedings as the gut is adapts and matures
Greater weight, length, and head circumference percentiles at discharge
Improved long term neurodevelopmental outcome
The nutritional support of extremely low birth weight infants is almost entirely dependent on parenteral nutrition. There is growing evidence that early use of TPN may minimize losses and improve growth outcomes.

9. Indications for TPN Prematurity < 1500 grams
GI anomalies or surgery
Feeding intolerance / ileus
Necrotizing enterocolitis
Cardiac disease
Chronic diarrhea
Pulmonary disease
Severe asphyxia
TPN indicated in all infants for which enteral feeds is contraindicated or delivers < 75% of requirements
ENTERAL is always preferred route of nourishing babies. TRophic feeds promote ongoing maturity of the GI tract, avoid villous atrophy from disuse, and promote release of gut hormones.

10. Benefits of Early Enteral Nutrition
Stimulates gut maturation
Increases gut hormone release
Improves gut motility
Prevents gut atrophy
Decreased release of proinflammatory mediators
Shortens time to achieving full feedings
Decreases length of hospitalization
Does not lead to an increased incidence of NEC

11. Feeding Premature Infants
Birth Weight 500–1250g: Start at mL/kg/d x 3-5 days, then increase by mL/kg/day
Birth Weight 1250g up to gestation 34 6/7 wks: Start at mL/kg/d x 1 day, then Increase by mL/kg/d. Note that nippling babies may be advanced more quickly
Gestation > 35 wks: Treat as full term
For all weights:
Change to 22 kcal/oz at 80 mL/kg/d
Change to 24 kcal/oz at 100 mL/kg/d
Consider making no volume increases on days when caloric density changed
D/C IL at mL/kg/d
D/C HA and DL at 120 mL/kg/d

12. Advantages of Human Milk for VLBW Infants
Quality of protein
Trophic effects on the developing GI tract
Rapid gastric emptying
Human milk Lipase
LCPUFA

13. Nutritional Goals
Provide sufficient energy and nitrogen to prevent catabolism and to achieve positive nitrogen balance
Maintain postnatal growth at normal rate: (15-30 grams/day)
Non protein caloric intake of 60 cal/k/d with an AA intake of gm/k/d can achieve an anabolic state; cal/k/d with same AA concentration can result in nitrogen retention at fetal rate
Essential components are carbohydrates,electrolytes, protein, lipids, vitamins, trace minerals
Ultimate goal is to deliver cal/k/d using dextrose, amino acids and lipids
Initial goal is to provide sufficient energy and nitrogen to prevent catabolism and to achieve a positive nitrogen balance.
Calories provided by CHO and fat.
TPN should provide suffient protein for protein turnover and tissue growth.
Caloric intake of kcal/kg/day approximates energy expenditure---reasonable goal for 1st few days of life.
However, to support normal rates of growth during TPN, kcal/kg/day are required. Most of these calories are supplied by lipid and glucose.
Energy requirements for the sick VLBW infant may be higher.

14. Nutritional Goals Non nitrogen calories: 65kcal/kg/day by 5 days
Combined enteral and parenteral nutrition: kcal/kg/day

15. Calculation of Calories
Calculation of non-nitrogen calories:
Dextrose kcal/gram
20% intralipid kcal/ml
Protein cal/gram
Glucose infusion rate: 6-8mg/kg/min
GIR: x concentration x rate
weight
Most calories are provided by lipid and glucose.

16. TPN: Carbohydrates Carbohydrates Exclusively glucose
With increased glucose concentration, there is increased osmolarity
Should provide 55-65% of total kilocalories
Maximum concentration is 12.5% peripherally
Begin with glucose infusion rate (GIR) of 6 mg/kg/min and gradually advance to mg/kg/min
GIR: x concentration x rate
weight
Glucose is most readily available to the brain.

17. TPN: Protein Goal is to prevent negative energy and nitrogen balance
High rates of protein turnover supply protein synthesis, tissue remodeling, and growth
Early initiation of protein reverses negative nitrogen balance.
Should provide 7-10% of total calories
Failure to provide adequate protein can have a serious impact on the long term outcome of extremely premature infants.

18. TPN: Lipids
Essential fatty acid deficiency avoided with use of gm/kg/day
Provides additional energy
Should provide 30-50% of total calories
Limit to 3 g/kg/day
Infuse over 20 hours
Monitor serum TG levels (accept < 150 mg/dL)

19. Daily Requirements of TPN
Calories kcal/kg or as needed
H ml/kg or as needed
Protein gm/kg
Lipid gm/kg

20. Daily Requirements of lytes, vitamins and minerals
Na mEq/kg
K mEq/kg
Ca mg/kg
Phosphorus mM/kg
Magnesium mEq/kg
Multivitamins ml (40%/kg/day)
Trace elements mL/kg/day
(Copper, zinc, chromium, manganese)
Zinc mcg/kg/day (prematures)
250 mcg/kg/day (term<3mos)
100 mcg/kg/day (term >3mos)
Selenium mcg/kg/day
Carnitine mg/kg/day
Extremely important to provide sufficient Ca/Phos to prevent bone demineralization

21. TPN: Practical Approach
Begin starter TPN in all preemies <1800g
Begin TPN within 24 hours of delivery
Dextrose: Begin with 4-6 mg/kg/min and advance to mg/kg/min.
Amino acids: Begin with 2 gm/kg/day and advance by 1gm/kg daily to max of 4 gm/kg/day.
Lipids: Begin with 0.5 gm/kg/day and advance gradually to max of 3 gm/kg/day.
Assess glucose tolerance.

22. Parenteral Nutrition Weaning
After enteral feeds have been established and tolerated, begin to decrease parenteral nutrition for total fluid ml/k/d.
When enteral feeds reach ~80 ml/k/d, discontinue Intralipids and fortify feeds to 22 cal/oz.
At ~ ml/k/d of enteral intake discontinue parenteral nutrition and central line.

23. Monitoring Monitor daily weights
Monitor head circumference, length weekly
Monitor Lytes, Ca as needed. Monitor phos, Mg, albumin, BUN, Cr, total and direct bili, SGPT, alk phos, triglyceride weekly
Consider: zinc, copper, carnitine, and selenium levels at 2-3 months

24. Complications of TPN Catheter related:
Thrombus (SVC syndrome, chylothorax)
Infection
Extravasation (pleural and pericardial effusions)
Air or fat embolus
Infiltration with tissue injury

25. Complications of TPN Metabolic: Electrolyte imbalance
Hypo-hyperglycemia
Hyperlipidemia
Trace mineral and Vit deficiency
Cholestasis
Osteopenia

26. Etiologies of Inadequate Growth
Actual intake too low
Volume of intake not increased for weight gain
Fore milk feedings
Human milk fortifier not added in correct proportions
Low sodium
Low protein intake
Weaning from incubator too rapidly