Issue 129 premature infant feeding

PAEDIATRIC

PREMATURE INFANT FEEDING Jacqui Lowdon Paediatric Dietitian, Leeds Children’s Hospital

Jacqui is a Clinical Specialist in Paediatric Cystic Fibrosis at Leeds Children's Hospital. She previously specialised in gastroenterology and cystic fibrosis.

Although her career to date has focused on the acute sector, Jacqui has a great interest in paediatric public health.

Preterm infants are those born before 37 weeks completed gestation.

Preterm birth is the primary cause of neonatal death worldwide and carries lifelong risks to health.1,2 Immaturity-related conditions, such as respiratory and cardiovascular disorders, remain the most common cause of infant deaths in the UK.3 However, a recent publication4 has demonstrated that there has been an increase in survival of very preterm infants in England over 2008-2014 (2008: 88.0%; 2014: 91.3%), with the greatest improvement at 22+0- 23+6 weeks.

The more preterm and smaller an infant is at birth, the more vulnerable they are nutritionally. The primary aim of nutrition support in preterm infants is to achieve growth similar to that of normally growing foetuses of the same gestational age, but there is also strong evidence that early nutrition affects neuro-cognitive outcomes5,6 and motor outcomes, such as the presence or severity of cerebral palsy.7,8 Therefore, everyone involved in providing care for preterm infants, needs to be aware

of the critical importance of good nutrition in both the short and long term.

NUTRITIONAL CONSEQUENCES OF BEING BORN TOO EARLY

Table 1 summarises the nutritional differences between a full term infant and one born at 24 weeks gestation.

Over the first few months, the adequacy of the nutrition provided on the neonatal unit will influence whether the infant will continue to develop.

Table 1: Nutritional differences - full term versus preterm Term infant

Preterm infant

37-40 weeks gestation, where intrauterine environment has been appropriate

24 weeks gestation

Body weight of >2.5kg, doubling within the first year of life

Body weight of around 600g

Skeleton to protect from the physical environment, and by one year of age, supporting the infant

Skeleton inadequately calcified and at high risk of fracture

Musculature sufficiently developed to allow inflation of the lungs, breastfeed and move

Musculature insufficiently developed to inflate lungs

Insulating layer of fat around organs and under skin, also providing protection and an energy reserve

No adipose stores to provide protection, insulation or energy reserves

Sufficient iron stores for first three to four months

No iron stores

Structurally and physiologically mature digestive system to process nutrition

A digestive system whose structure cannot support the transit of food and has not developed adequate enzyme support to digest adequate nutrition

A brain that will co-ordinate processes and communicate its needs

Primitive and underdeveloped brain

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Table 2: Summary of main ESPGHAN recommendations10,15 Nutrient

Recommended intake

Fluid ml/kg/day

135-200

Energy kcal/kg/day

110-135

Protein g/kg/day (depends on infant’s body weight)

Body weight <1kg: 4.0-4.5 Body weight 1-1.8kg: 3.5-4g

Sodium mg/kg/day

69-115

Potassium mg/kg/day

66-132

Calcium mg/kg/day

120-140

Phosphate mg/kg/day

60-90

Vitamin A µg RE/kg/day

400-1,000

Vitamin D*µg/day (not per kg/day)

20-25

Folic acid µg/kg/day

35-100

Iron mg/kg/day

2-3 from 2-6 weeks of age (from 2-4 weeks of age in ELBW infants)

Table 3: Recommended protein to energy ratios as per ESPGHAN guidelines10 Weight

Protein g/100kcal

Protein:energy ratio

1-1.8kg

3.2-3.6g/100kcal

12.8-14.4%

<1kg

3.6-4.1g/100kcal

14.4-16.4%

NUTRITIONAL GUIDELINES

No UK guidelines exist for enteral feeding of preterm infants and so international guidelines are used.9,10,11,15 Table 2 summarises the main ESPGHAN recommendations.10,15 ENERGY REQUIREMENTS

Energy requirements are higher for preterm infants, estimated to be 110-135kcal/kg/day10 as opposed to 96-120kcal/kg/day for term infants.12,15 In cases of intrauterine growth restriction (IUGR), higher requirements are not always necessary, as it will depend on the cause of the IUGR. PROTEIN REQUIREMENTS

Recommended protein for preterm infants:10,15 • Infant body weight 1-1.8kg 3.5-4g/kg/day • Infant body weight <1kg 4-4.5g/kg/day

No benefit has been reported for feeding >4.5g/kg/day.

As well as the level of protein required, attention also needs to be made to the protein to

energy ratio: ‘Synthesis of new tissue is energy intensive and strongly affected by the intake of protein and other nutrients; thus, achieving an adequate energy to protein ratio is as important as providing adequate energy intake.’10,15 This is particularly important if supplements such as a glucose polymer or fat emulsion are added to the feed (Table 3).

AGE-DRIVEN VERSUS INFANT-DRIVEN NUTRITION RECOMMENDATIONS

Despite the availability of these international nutrition recommendations, preterm infants remain vulnerable to suboptimal nutrition. This standard approach of assessing nutrient intakes based on chronological age may make it difficult to identify the origin of nutrient deficits and/or excesses.

A recent publication13 compared the nutrient intakes of preterm infants during the period of weaning from parenteral nutrition (PN) to enteral nutrition (EN), called the transition (TN) phase, and compared the data with those analysed using the standard ‘chronological age’ approach, www.NHDmag.com November 2017 - Issue 129

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THIS IS HUGE After months of coping with the sleepless worry and heartbreaking cries of his cow’s milk allergy, suddenly, a little moment like this doesn’t seem so little after all.

• Proven efficacy – hypoallergenic and has been shown to relieve symptoms1,2 • Proven to be well tolerated – 96% of infants tolerated Similac Alimentum3 • Palm oil and palm olein oil free – supports calcium absorption and bone mineralisation4 SIMILAC ALIMENTUM. FOR BIG LITTLE MOMENTS.

REFERENCES: 1. Sampson HA et al. J Pediatr 1991;118(4): 520-525. 2. Data on file. Abbott Laboratories Ltd., 2013 (Similac Alimentum case studies). 3. Borschel MW and Baggs GE. T O Nutr J 2015;9:1-4. 4. Koo WWK et al. J Am Coll Nutr 2006;25(2):117-122.

IMPORTANT NOTICE: Breastfeeding is best for babies, and is recommended for as long as possible during infancy.

Similac Alimentum is a Food for Special Medical Purposes and should be used under the supervision of a healthcare professional.

Date of preparation: July 2015 RXANI150143

Table 4: High risk infants <27 weeks or <1,000g birthweight Haemodynamically unstable on inotropes Previous NEC or high risk for NEC Recent abdominal surgery Growth restricted infants with absent or reversed end diastolic flow

assessing whether the identification of nutrient deficits and/or excesses can be improved. The nutrition phase analysis approach revealed substantial macronutrient and energy deficits during the TN phase. In particular, deficits were identified as maximal during the EN-dominant TN phase (enteral feeds ≥80ml/kg/d). In contrast, the chronological age analysis approach did not reveal a corresponding pattern of deficit occurrence, but rather intakes that approximated or exceeded recommendations. The authors concluded that actual intakes of nutrients, analysed using a nutrition phase approach to evaluating nutrition support, allowed a more infant-driven rather than age-driven application of nutrition recommendations. This approach highlighted nutrient deficits occurring during the transition phase. Overcoming nutrient deficits in this nutrition phase should be prioritised to improve the nutrition management of preterm infants.

EXPECTED WEIGHT GAIN

Intrauterine growth rate of approximately 15g/ kg/day is the most commonly used and accepted rate of weight gain for preterm infants, although this can be difficult to achieve.9 However, an accelerated weight gain in preterm infants should be avoided, as this has demonstrated detrimental consequences on longterm health, such as cardiovascular disease.14 When monitoring growth, the UK-WHO Growth Charts should be used. When correcting for gestation, the following guidance is accepted: • Gestation ≥37 weeks - no correction • Gestation 32 to 36+6 correct until age 1 year • Gestation 23 to 31+6 correct until age 2 years When calculating requirements, the actual weight should be used. In cases where the actual weight is lower than the birthweight or their highest dry weight, use the birthweight or highest dry weight.

CHOICE OF FEED

Breast milk Breast milk is the feed of choice for preterm infants, with all of its benefits being well documented.

Where fortification is required, expressed breast milk (EBM) should be fortified with a commercial multicomponent breast milk fortifier (BMF) suitable for the preterm infant.

As unfortified BMF cannot meet the needs of preterm infants <1.5kg, it can be commenced in stable preterm infants, usually once 150ml/kg/ day EBM is tolerated. Fortification should then continue until the infant is thriving.

In cases where a supplementary preterm formula is given in addition to EBM and BMF, then the BMF should be stopped once 50% of requirements are given as formula, to prevent an excess of protein.

It is important to carefully consider when to use a BMF in high risk preterm infants. Table 4 lists high risk infants.

PRETERM FORMULA

Preterm infants who are not able to receive breast milk and are <2kg and <35 weeks, should be placed onto a preterm formula.

There are three preterm formula milks available in the UK: • SMA PRO Gold Prem 1 (partially hydrolysed formula) • Nutriprem 1 low birth weight (whole protein formula) • Hydrolysed Nutriprem (extensively hydrolysed formula) Additional vitamin and mineral supplements are not required if the infant is on 150ml/kg/day of a preterm formula.

These formulas should be continued until the infant is thriving, reaching 2.0-2.5kg and/ or discharged. Depending on growth achieved, www.NHDmag.com November 2017 - Issue 129

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PAEDIATRIC a post discharge or term formula can be used on discharge.

Supplements Various supplements of vitamins and minerals will need to be added in depending on the feed used.

If a preterm formula is being given at 150mls/ kg/day, then phosphate, sodium and calcium supplements will only need to be prescribed based on individual assessment.

If a term infant formula is used, then 0.6mls multivitamin drops, an iron supplement and folic acid (only until term) will need to be prescribed, with phosphate, sodium and calcium supplements based on individual assessment.

Infants fed on unfortified EBM will require 0.6mls multivitamin drops, an iron supplement and folic acid (only until term), with phosphate, sodium and calcium supplements based on individual assessment.

For those infants fed on EBM with a suitable BMF, depending on which BMF is used, they will require an iron supplement with phosphate, sodium and calcium supplements based on individual assessment.

POST-DISCHARGE NUTRITION

If breastfed on discharge, then this should be encouraged post-discharge, with added supplements. Multivitamin drops (0.6ml) will always be required until first birthday. Most also require iron (1ml) until six months of age.

If formula-fed and poor growth, a nutrientenriched post-discharge formula (NEPDF) such as Nutriprem 2 or SMA PRO Gold Prem 2 is recommended. Each infant will need to be individually assessed, as some may require this until six months corrected age. Once the NEPDF has been stopped, a term formula should be used until 12 to 18 months corrected age, depending on the nutritional adequacy of the complementary diet.

CONCLUSION

Unlike respiratory, cardiac or neurological disease, nutritional morbidity can often be hidden. Today, many preterm infants have minimal respiratory or neurological morbidity, but good nutritional status is essential for every baby, and the longterm adverse effects that poor nutritional care might cause needs to be highlighted. Nutritional management should start as soon as the infant is born, continuing during the post-discharge period to help achieve optimal outcomes.

References 1 Lawn JE, Cousens S, Zupan J for the Lancet Neonatal Survival Steering Team. 4 million neonatal deaths: When? Where? Why? Lancet 2005; 365: 891-900 2 Saigal S, Doyle LW. An overview of mortality and sequelae of preterm birth from infancy to adulthood. Lancet 2008; 371: 261-9.doi:10.1016/ S0140-6736(08)60136-1 3 Childhood mortality in England and Wales: 2015. Office for National Statistics. www.ons.gov.uk/peoplepopulationandcommunity/ birthsdeathsandmarriages/deaths/bulletins/childhoodinfantandperinatalmortalityinenglandandwales/2015. Accessed 7th October 2017 4 Shalini Santhakumaran, Yevgeniy Statnikov, Daniel Gray, Cheryl Battersby, Deborah Ashby, Neena Modi, on behalf of the Medicines for Neonates Investigator Group. Survival of very preterm infants admitted to neonatal care in England 2008-2014: time trends and regional variation. BMJ June 2017. Downloaded from http://fn.bmj.com/7th October 2017 5 Cooke RWI. Are there critical periods for brain growth in children born preterm? Arch Dis Child: Fetal Neonatal Ed 2006; 91 (1): 17-20 6 Isaacs EB, Gadian DG, Sabatini S et al. The effect of early human diet on caudate volumes and IQ. Pediatr Res 2008; 63 (3): 308-14 7 Lucas A, Morley R, Cole TJ. Randomised trial of early diet in preterm babies and later intelligence quotient. BMJ 1998; 317 (7171): 1481-87 8 Dabydeen L, Thomas JE, Aston TJ, Hartley H, Sinha SK, Eyre JA. High-energy and -protein diet increases brain and corticospinal tract growth in term and preterm infants after perinatal brain injury. Pediatrics 2008; 121 (1): 148-56 9 Tsang RC, Lucas A, Uauy R, Zlotkin S. Nutritional needs of the preterm infant: scientific basis and practical guidelines. Baltimore: 2006, Williams & Wilkins 10 Agostoni C, Buonocore G, Carnielli VP, De Curtis M, Darmaun D, Decsi T, Domellรถf M, Embleton ND, Fusch C, Genzel-Boroviczeny O, Goulet O, Kalhan SC, Kolacek S, Koletzko B, Lapillonne A, Mihatsch W, Moreno L, Neu J, Poindexter B, Puntis J, Putet G, Rigo J, Riskin A, Salle B, Sauer P, Shamir R, Szajewska H, Thureen P, Turck D, van Goudoever JB, Ziegler EE. Enteral Nutrition Supply for Preterm Infants: Commentary from the European Society for Paediatric Gastroenterology, Hepatology and Nutrition Committee. (ESPGHAN). JPGN 2010; 50: 1-9 11 Koletzko B, Poindexter B, Uauy R. Nutritional Care of Preterm Infants. Scientific Basis and Practical Guidelines. Karger 2014.

12 Scientific Advisory Committee on Nutrition. Dietary Reference Values for Energy. SACN, London, 2011.

13 Brennan A, Fenton S, Murphy B, Kiely M. A Missing Link in the Nutrition Management of Preterm Infants. Journal of Parenteral and Enteral Nutrition. March 21, 2017. https://doi.org/10.1177/0148607116686289 Accessed 7th October 2017.

14 Singhal A, Cole TJ, Fewtrell M, Lucas A. Breast milk feeding and lipoprotein profile in adolescents born preterm follow-up of a prospective randomised study. Lancet 2004; 363: 1571-1578 Transition Phase Nutrition Recommendations 15 GOSH guideline: Nutrition: enteral nutrition for the preterm infant at www.gosh.nhs.uk/health-professionals/clinical-guidelines/ nutrition-enteral-nutrition-preterm-infant

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