Neonatal and Infant Nutrition Dr Russell Peek Paediatric HST Core Training Day Gloucester, 4th October 2007
Introduction • What does ‘nutrition’ mean to you?
The OED definition Nutrition (noun) • the process of taking in and assimilating nutrients. • the branch of science concerned with this process. DERIVATIVES nutritional adj. nutritionist noun. ORIGIN Latin, from nutrire ‘nourish’.
Textbook answer • Nelson’s Textbook of Paediatrics • achievement of satisfactory growth and avoidance of deficiency states.
Aims • To explore the knowledge base behind key competencies in nutrition for paediatricians • Reference: A Framework of Competences for Core Higher Specialist Training in Paediatrics (RCPCH, 2005.)
Objectives • By the end of this morning, you will • understand the effects of fetal growth restriction on short- and long-term health • understand the principles and importance of nutrition in the neonatal period including assessment of nutritional status • be able to make appropriate recommendations to address feeding problems and faltering growth
Fetal nutrition • Parenteral (mostly!) • Stores are laid late in gestation • At 28 weeks, a fetus has: • 20% of term calcium and phosphorus stores • 20% of term fat stores • About a quarter of term glycogen stores
Adaptation to nutrition after birth • Gut adaptation is regulated by • Endocrine factors • Intraluminal factors • Breast milk hormones and growth factors • Bacteria
Feeding the term infant • Breast feeding achieves • Nutrition • Immunological and antimicrobial protection • Passage of breast milk hormones and growth factors • Provision of digestive enzymes • Facilitation of mother-infant bonding
Supplementing breast milk • Should be unnecessary, but • Vitamin K levels are low • Vitamin D levels are low in areas of little sunlight • Iron levels are low (but very well absorbed)
Artificial Feeds • Term formulas are broadly similar • May be whey or casein based • International agreed standards for constituents
Artificial feeding • Practical considerations for making up feeds • Water softeners increase sodium content • Repeated or prolonged boiling can increase sodium content of water • Bottled water can contain high levels of carbon dioxide, sodium, nitrate and fluoride.
Monitoring feeding • Maternal sensation of engorgement and emptying • Frequency of feeding • Wet nappies • Stools • Jaundice • Weight
Support for breast feeding mothers • Midwife • Infant feeding specialist • Breast feeding support groups • National Childbirth Trust
From little acorns… • The obstetric team ask you to talk to a mother who is being induced at 31 weeks gestation as she is ‘small for dates’. • What further information would you like?
Mrs Oak • 28 year old primigravida • 5’2, 80kg • Smokes 5 cigarettes daily • Concerns about growth from 20 weeks • Latest ‘dopplers’ show absent EDF • Proteinuria and hypertension
In groups, plan your chat • How will you counsel the family? • Consider particularly: • Risks of preterm delivery vs risk of continuing pregnancy • Short term risks • Approach to feeding • Long term outcome
Short term risks of IUGR • Obstetric • Intrauterine death • Intrapartum asphyxia
Short term risks of IUGR • Paediatric • Hypoglycaemia • Necrotising enterocolitis • Increased risk of problems of prematurity • (hypothermia) • (polycythaemia)
NEC and IUGR • Case-control study (n=74) • at 30-36 weeks GA, birth weight <10th centile is a significant risk factor • OR 6 (1.3-26)1 • Observational study (n= 69) • At 30-36 weeks 71% of cases were <10th centile2 • 1 Beeby and Jeffrey. 1991, ADC:67:432-5 • 2 McDonnell and Wilkinson. Sem Neonatol 1997
NEC and IUGR: Why? • Pathogenesis of NEC requires • enteral feeding • gut ischaemia • bacterial infection • Abnormal gut blood flow recognised in IUGR • Ischaemic damage or reperfusion injury?
Abnormal dopplers and NEC • In 9 of 14 studies, AREDF led to an increased risk of NEC • OR 2.13 (95%CI 1.49 to 3.03) • Dorling J, Kempley S, Leaf A. Feeding growth restricted preterm infants with abnormal antenatal Doppler results. Arch. Dis. Child. Fetal Neonatal Ed. 2005; 90: F359-F363
So how to feed? • Delay start? • Use non-nutritive feeds? • Increase slowly? • Use friendly bacteria?
Cochrane review: early vs late feeding • 72 babies in 2 studies • Early feeders had • Fewer days parenteral nutrition • Fewer investigations for sepsis • No difference in • NEC • Weight gain
Cochrane review: rapid vs slow increase • 369 babies in 3 studies • Rapid: 20 to 35 ml/kg/day • Slow: 10 to 20 ml/kg/day • Rapid group: • reached full enteral feeds and regained birthweight faster • No difference in NEC rate or length of stay
Cochrane review: minimal enteral nutrition • 380 babies in 8 studies • 12 to 24 ml/kg/day for 5 to 10 days • MEN group • Faster to full enteral feeds • Shorter length of stay • No difference in NEC
Probiotics for preventing NEC • Systematic review of 1393 VLBW infants treated with a variety of organisms • Reduced risk of • NEC (RR 0·36, 95% CI 0·20–0·65) • Death (RR 0·47, 0·30–0·73) • Achieved full feeds faster • No difference in rates of sepsis • Deschpande et al, Lancet 2007
Feeding small or preterm infants: Choices • Human milk • Mother’s own • Banked donor milk • Fortified • Artificial • Term formula • Preterm formula • Parenteral Nutrition
Parenteral Nutrition • If an infant can’t, won’t or shouldn’t be fed enterally • What’s in the bag? • Fluid • Carbohydrate • Protein • Fat • Minerals and Trace Elements
Energy • Requirements • Basal metabolic rate • Physical activity • Specific dynamic action of food • Thermoregulation • Growth
Energy • Requirements kcal/kg/day • Basal metabolic rate 40 • Physical activity 4+ • Specific dynamic action of food (10%) • Thermoregulation variable • Growth 70 (To match in-utero growth of 15g/kg/day)
Protein • With glucose infusion alone, infants lose 1-2% of endogenous protein stores daily • 1g/kg/day gives protein balance • 2.5 to 3.5g/kg/day allows accretion • nb energy requirement • Safe to start soon after birth
Fat • Energy source • Essential fatty acid source (intralipid) • Cell uptake and utilisation of free fatty acids is deficient in preterm infants • Start at max 1g/kg/day, increasing gradually to 3g/kg/day (less if septic)
Benefits of PN • Earlier, faster weight gain • Avoidance of problems associated with enteral feeds
Risks of PN • Line associated sepsis • Line related complications (eg thrombosis) • Hyperammonaemia • Hyperchloraemic acidosis • Cholestatic jaundice • Trace element deficiency
Human milk advantages • Protection from NEC • Improved host defences • Protection from allergy and eczema • Faster tolerance of full enteral feeds • Better developmental and intellectual outcome
Human milk shortcomings if preterm • Human milk may not provide enough • Protein • Energy • Sodium • Calcium, phosphorus and magnesium • Trace elements (Fe, Cu, Zn) • Vitamins (B2,B6,Folic acid, C,D,E,K)
Breast milk fortifiers • Improved • short term growth • nutrient retention • bone mineralisation • Concerns • trend towards increased NEC
Term vs preterm formulas • Term formulas do not provide for preterm protein, calcium, sodium and phosphate requirements, even at high volumes • Term formula (vs preterm formula) fed infants • Grow more slowly • Have lower developmental score and IQ at follow up
Feeding preterm infants: aim “To provide nutrient intakes that permit the rate of postnatal growth and the composition of weight gain to approximate that of a normal fetus of the same gestational age, without producing metabolic stress” American Academy of Pediatrics Committee on Nutrition