Nutrition in the Neonate

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* 50 kcal/kg/day Activity 15 kcal/kg/day Cold Stress 10 kcal/kg/day Nutrition Processing 50 kcal/kg/day Total 120 kcal/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

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

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

9. Indications for TPN • Prematurity < 1500 grams • GI anomalies or surgery • Feeding intolerance / ileus • Necrotizing enterocolitis • Cardiac disease • Chronic diarrhea • Pulmonary disease • Severe asphyxia

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 10-20 mL/kg/d x 3-5 days, then increase by 10-20 mL/kg/day • Birth Weight 1250g up to gestation 34 6/7 wks: Start at 20-30 mL/kg/d x 1 day, then Increase by 20-30 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 100-120 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 2.5-3 gm/k/d can achieve an anabolic state; 80-85 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 100-110 cal/k/d using dextrose, amino acids and lipids

14. Nutritional Goals Non nitrogen calories: • 65kcal/kg/day by 5 days • 90-110 kcal/kg/day by 7 days • Combined enteral and parenteral nutrition: 100-130kcal/kg/day

15. Calculation of Calories Calculation of non-nitrogen calories: • Dextrose 3.4kcal/gram • 20% intralipid 2kcal/ml • Protein 4 cal/gram

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 10-12 mg/kg/min GIR: 0.167 x concentration x rate weight

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

18. TPN: Lipids • Essential fatty acid deficiency avoided with use of 0.5-1 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 90-110kcal/kg or as needed H20 125-150 ml/kg or as needed Protein 2.5-4 gm/kg Lipid 2.4 gm/kg

20. Daily Requirements of lytes, vitamins and minerals Na 3-4 mEq/kg K 2-3 mEq/kg Ca 50-100mg/kg Phosphorus 1-1.5 mM/kg Magnesium 0.5-1mEq/kg Multivitamins 10ml (40%/kg/day) Trace elements 1mL/kg/day (Copper, zinc, chromium, manganese) Zinc 400mcg/kg/day (prematures) 250 mcg/kg/day (term<3mos) 100 mcg/kg/day (term >3mos) Selenium 1-2 mcg/kg/day Carnitine 10mg/kg/day

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 10-12 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.

22. Parenteral Nutrition Weaning • After enteral feeds have been established and tolerated, begin to decrease parenteral nutrition for total fluid 120-150 ml/k/d. • When enteral feeds reach ~80 ml/k/d, discontinue Intralipids and fortify feeds to 22 cal/oz. • At ~100 -120 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