This article will provide an outline of the common conditions seen on a special care baby unit and will discuss the variety of nutritional solutions, based on the latest Tsang guidelines.

Common special care situations and their nutritional solutions:

The Preterm Infant

Preterm infants have limited stores of many nutrients at birth; this is because these are predominantly built up during the third trimester of pregnancy. Energy and protein requirements of the preterm infant are higher than those of the term infant, but vary according to the baby`s birth weight and gestational age. Fluid management can also be complicated due to high transdermal losses and fluid overload due to renal immaturity.

It is thus generally accepted that infants weighing ≤1500g at birth will require some parenteral nutrition whilst enteral nutrition is being established. It can take up to a month to establish full enteral nutrition¹.

A summary and comparison of the nutritional requirements of a term and preterm infant are listed in the table below:

Table 1 - Estimated Nutritional Requirements:

	Term Infant	Preterm Infant (Tsang et al.)2
Fluid (ml)	150ml/kg/d	160-220ml/kg/d
Energy (kcal)	100-115kcal/kg/d	110-150kcal/kg/d
Protein (g)	2.1g/kg/d (RNI)	2-4g/kg/d
Folic Acid (µg)	40µg/d (EAR)	25-50µg/kg/d
Vitamin C	15mg/d (EAR)	18-24mg/kg/d
Vit A (µg)	250µg/d (EAR)	210-450µg/kg/d
Vit D (µg)	8.5µg/d (RNI)	5-10µg/kg/d
Vit E (mg)	2.2mg/d

EAR-Estimated Average Requirements
RNI-Recommended Nutrient Intake

It is well known that breastmilk is the ideal and optimal source of nutrition for term-babies³. However, the special needs of the preterm infant must be considered in order to provide adequate nutrition to meet their needs and to encourage appropriate growth and development. Human milk can meet the nutritional needs of the preterm infant if given in adequate volumes and if it is tolerated². Maternal expressed breastmilk (MEBM) remains undoubtedly the milk of choice for enteral feeds. Besides the numerous known advantages, maternal preterm milk has also been shown to contain higher levels of a variety of nutrients than term milk². If optimal growth is not being achieved on full volumes of breastmilk, a commercially produced human milk fortifier can be added to the breastmilk to bring the total composition closer to that of preterm requirements³. It has been shown that multi-component fortification of human milk is associated with short-term improvements in weight gain, length and head growth⁴.

Breastmilk fortifiers, containing protein, carbohydrate, vitamins and minerals are commercially available and can easily be added to maternal or donor breastmilk before feeding. e.g Cow & Gate Nutriprem Breastmilk Fortifier. If a mother decides to stop breastfeeding, lactation fails or a mother needs to supplement breastfeeding, donor breastmilk or an appropriate, nutritionally complete preterm infant formula can be used.

Preterm infant formulae are available and are specifically formulated to meet the increased requirements of the preterm infant. e.g Cow & Gate Nutriprem 1, Aptamil Preterm.

All mothers should be encouraged to breastfeed on demand on discharge, but if this is not possible a nutrient enriched post-discharge formula (NEPDF), Cow & Gate Nutriprem 2 is also available. It is indicated when the infant reaches 2.5kg or is near discharge and can be continued until six months corrected age or until catch-up growth is achieved.

Necrotising Enterocolitis (NEC) is a serious inflammatory disease of the bowel occurring predominantly in preterm infants. It is managed with extended periods of total parenteral nutrition and gut rest and if necessary gastrointestinal surgery. In non-surgical NEC the period of bowel rest is 3-10 days depending on severity of disease².

Following NEC and a period on total parenteral nutrition enteral feeding is commenced slowly and cautiously, e.g. 15ml/kg/d² compared to the estimated average intakes of 160-220ml/kg/d. Maternal breastmilk and then donor breastmilk are again the first choice. If breastmilk is shown to not be tolerated and the infant is subsequently failing to thrive, has diarrhoea, large stoma losses or other signs of malabsorbtion, an extensively hydrolysed, preferably MCT-rich, formula is indicated. e.g. Cow & Gate Pepti Junior, Mead Johnson Pregestimil. If the above symptoms persist on an extensively hydrolysed formula, an amino acid based formula may be tolerated e.g Nutricia Neocate.

Short Bowel Syndrome (SBS)
SBS is a collection of disorders where a loss of intestinal length has occurred that compromises the ability to digest and absorb nutrients³. Symptoms of SBS usually occur when >75% of the small intestine has been resected³. Bowel resection can be secondary to various conditions such as NEC, Gastroschisis, malrotation and intestinal atresias. Parenteral nutrition is required to provide adequate nutrition for growth until full enteral feeding is tolerated. A combination of enteral and parenteral nutrition is usually necessary until the gut has adapted.

There is little evidence and research on the ideal nutrient mix for enteral formula if breastmilk is not tolerated. Some centres use elemental diets but this is based on personal experience and very old studies^2,3. In short bowel syndrome, the volume of enteral feeds tolerated is dependent on the length of small bowel remaining and the presence or absence of the ileo-caecal valve^2,3.

Maternal breastmilk is the enteral feed of choice and then donor breastmilk if maternal milk is not available. If these are not tolerated, an extensively hydrolysed formula e.g. Cow & Gate Pepti Junior or an amino acid based formula e.g. Nutricia Neocate would be indicated. Modular feeds are also used; they allow flexibility and enable different components of the diet to be manipulated individually.

Congenital Heart Disease (CHD) is commonly associated with malnutrition and growth retardation³.

Some of the factors that contribute to failure to thrive include increased total energy expenditure, sub-optimal intake, vomiting and frequent infections. In addition, infants with congenital cardiac defects have an increased risk of GOR, NEC and other disorders that can contribute to malnutrition³.

Breastmilk is the feed of choice for infants with congenital heart disease (CHD). Adequate growth in these infants requires an estimated intake of 150kcal/kg/d, which is the upper level of recommendations^2,5. Fortification of breastmilk should be considered early on to help meet the raised requirements and compensate for fluid restrictions often in place.

When breastmilk is not available an infant formula with a high nutrient density is suggested e.g. SMA High Energy, Nutricia Infatrini. Further fortification of the high energy formula with a carbohydrate/fat supplement is an option if adequate weight gain is not achieved on the high energy formula e.g. SHS Duocal³. If full feeds cannot be managed orally due to fatigue, anorexia or satiety, smaller feeds can be given at more regular intervals, or nasogastric feeding can be an option.

Chronic Lung Disease
Preterm infants are at risk of chronic lung disease possibly as a result of ventilation or oxygen toxicity. Failure to thrive is a major side effect of lung disease, as it results in increased energy expenditure, sub-optimal intake, metabolic disturbances and decreased gastrointestinal absorption².

Meeting raised nutritional requirements is often further complicated by fluid restrictions to manage pulmonary oedema. Breastmilk is the feed of choice for infants with Chronic Lung Disease. Due to the fact that their energy and protein requirements are significantly raised, breastmilk can be fortified with infant formula powders or breastmilk fortifier if weight gain is inadequate². Increased protein intake is important as it aids lean muscle growth and thus lung growth and development. A nutrient dense formula is usually the formula of choice for theses babies to help meet raised requirements e.g. SMA High Energy, Nutricia Infatrini².

Below is a table showing the breakdown of the nutritional composition of breastmilk and the alternatives discussed above.

Per 100ml	Term breastmilk6	Cow & Gate Nutriprem 1	Preterm breastmilk with 2 x 2.1g sachets Cow & Gate Nutriprem BMF7	Cow & Gate Nutriprem 2	Cow & Gate Pepti-Junior	Nutricia Neocate	Nutricia Infatrini	Cow & Gate first infant milk from newborn
Energy (kcal)	69	80	85	75	66	70	100	66
Protein (g)	1.3	2.5	2.6	2	1.8	1.9	2.6	1.3
Carbohydrate (g)	7.2	7.6	10	7.5	6.8	7.9	10.3	7.3
Fat (g)	4.1	4.4	4	4.1	3.5	3.4	5.4	3.5
Added MCT oil (%)	X	X	X	X	50	4	X	X
Sodium (mg)	15	50	50	28	18	17.6	25	17
Potassium (mg)	58	82	100	77	65	61.7	93	63
Calcium (mg)	34	120	87	94	42	68.5	80	50
Iron (mg)	0.07	1.4	0.09	1.2	0.8	1	1	0.53
Zinc (mg)	0.3	0.9	0.8	0.9	0.7	0.7	0.9	0.5
Vitamin A (µg RE)	58	180	130	100	52	77.6	81	55
Vitamin D (µg)	Trace	3	5	1.7	1.3	1.2	1.7	1.2
Vitamin E (mg α-TE)	0.34	3	2.6	2.1	1.1	0.5	1.2	1
Vitamin K (µg)	NS	6	6.3	5.9	4.7	3.1	6.7	4.5
Folic Acid (µg)	5.0	28	53.1	20	8.9	5.6	15	12
Osmolality (mOsmol/kg H20)	NS	360	NA	340	210	360	350	340

Figures correct at time of publishing, please check manufacturers data cards for latest information.
NS-not specified
NA-not currently available

Weaning on special care
Governmental guidelines recommending weaning at 6 months are not necessarily applicable for all babies on special care units.

Signs that an infant is ready to commence weaning include showing interest in other people eating, putting things into their mouth, seeming less satisfied with milk alone and being able to support their own head ^{3, 8}.

Weaning a premature baby is recommended between 5 and 7 months from the date of birth (i.e. non corrected age). The suggested upper limit to start weaning is 7 months post delivery^{3, 8}. Once weaning has started it is suggested that it progresses as per government guidelines.

Infants for whom it is not physically possible to wean within the suggested time period should have a programme of positive oral stimulation instituted wherever possible. The involvement of a specialist Speech and Language Therapist is desirable to promote this³

Conclusion
Nutrition plays a very important role in all cases on a Special Care Unit. Maternal breastmilk is always the first choice due to its many beneficial components. Babies on special care often have specific nutritional requirements and their feeds need to be modified accordingly. Breastmilk can be given in larger volumes or be fortified to provide the extra nutrition. If neither maternal or donor breastmilk are available, a variety of specialised infant formulae can also be used to aid provision of optimal nutrition, growth and development.

Click here for more information on the Cow & Gate Nutriprem range or to download a copy of our Specialist Infant Milks leaflet If parents would like information on feeding thier preterm baby why not tell them to visit the Cow & Gate website hereClick here to view the latest research on preterm infant milk formulas

References:

1. Mihatsch W, et al. Prebiotic oligosaccharides reduce stool viscosity and accelerate gastrointestinal transport in preterm infants. Acta Paediatr 2006; 95: 843-848.
   
2. Tsang R et al. Nutrition of the Preterm Infant, 2nd Edition. Cininnati: Digital Educational Publishing, Inc, 2005
3. Shaw, V Lawson, M. Clinical Paediatric Dietetics, 3rd Edition. Oxford: Blackwell Publishing, 2007.
4. Kuschel CA, Harding JE. Multicomponent fortified human milk for promoting growth in preterm infants. Cochrane Database of Systematic Reviews 2004, Issue 1.
5. Barton J et al. Energy expenditure in Congenital Heart Disease. Arch Dis Child, 1994; 70: 5-9.
6. Food Standards Agency. McCance and Widdowson`s The Composition of Foods, 6th Summary Edition. Cambridge: Royal Society of Chemistry, 2002.
7. Wharton BA. Nutrition and Feeding of Preterm Infants. Oxford: Blackwell Scientific Publications, 1987.
8. BLISS- The premature baby charity. Weaning your Premature Baby, 4th Edition. London: BLISS, 2007.