Chapter 9. Feeds and growth
Feeding and adequate growth are vital to both the preterm and term infant. After birth, the infant undergoes many changes, not only in gut structure but also in gut function and metabolism. Premature infants are slow to establish effective peristalsis and suck and swallow reflexes may be some weeks or even months before becoming strong enough to allow full oral feeding. An infant who has required prolonged ventilation may become orally defensive and in the worst cases may not tolerate any oral feeding and require long-term nasogastric tube feeding. In addition the preterm gastrointestinal tract appears to be particularly vulnerable to ischaemic damage, and necrotising enterocolitis may occur in up to 8% of neonatal admissions. 1 It is not surprising that studies have documented a degree of postnatal growth failure in the majority of infants born prematurely. For those born extremely prematurely growth failure may be prolonged and severe and final stature may be affected.
It is now clear that nutrition and growth, both as a fetus and in the early weeks of postnatal life, may have major implications on long-term health. The concept of programming suggests that cardiovascular and cerebrovascular disease as well as insulin resistance and diabetes may have an early origin in some individuals and there is a small amount of evidence to suggest that premature infants may be more vulnerable to this early programming than are other, more mature infants. Infants who are born small for gestational age are at risk of developing later risk factors for cardiovascular disease, such as high blood pressure. Promotion of postnatal growth was thought to ameliorate these effects, but there is now evidence in human infants and other animals born prematurely that promotion of growth by increased postnatal nutrition increases later cardiovascular risk. It would therefore seem crucial that while preterm and small for gestation age infants should be fed appropriately, they should not be ‘over fed’ in the neonatal period. 2
Once enteral feeding has been established, the most common problem seen on a day-to-day basis is gastro-oesophageal reflux. A recent paper documented that 25% of all extremely low birth weight (<1 kg) infants are discharged home from the neonatal unit on treatment for reflux. 3 The diagnosis and management of reflux remains a subject of considerable debate with a relative lack of strong consistent evidence.
This chapter aims to cover the common problems described above as well as other topics such as nutritional supplementation.
QUESTION 1
i) A baby is reviewed in clinic and his mother describes episodes of vomiting post feeds and says that he seems uncomfortable. She has tried positioning the baby after feeds but feels this has not made any difference. A friend has said that her baby has gastro-oesophageal reflux and she has been extensively reviewing this subject on the internet. She would like you to discuss the pros and cons of the following investigations for GOR.
a. pH probe
b. Oesophageal manometry
c. Oesophageal impedance
d. Fluoroscopy
e. Endoscopy
f. Chiropractice
g. Empiric therapy.
ii) Mother elects to have empiric treatment. Which of the following treatments would you suggest?
a. Cisapride
b. Gaviscon
c. Gripe water
d. Antacids
e. Thickeners
f. Hydrolysed formula milk
g. Erythromycin
h. Ranitidine
i. Metoclopramide
j. Omeprazole
k. Domperidone
l. Buscopan (hyoscine butylbromide)
m. Coleif
n. Infacol.
QUESTION 2
Match the following milks and ingredients/uses
| Infatrini | Milk protein, soy and lactose free |
| Nutramigen | Gluten free |
| Neocate | Gluten, sucrose and lactose free |
| Infasoy | Disaccharide/whole protein intolerance with medium-chain triglycerides |
| Peptijunior | Lactose intolerance, galactosaemia |
QUESTION 3
Which of the following statements about iron and its supplementation are correct?
i) Maternal iron deficiency affects 30–50% of pregnancies
iii) Maternal smoking can cause perinatal iron deficiency
iv) Maternal diabetes can cause perinatal iron deficiency
v) Iron supplementation prevents early anaemia
vi) Can lead to an increased risk of infection
vii) Should be given at the same time as calcium and phosphorus supplements
viii) Can be started safely at about 4–6 weeks of life
ix) Is only needed in infants fed formula milk
x) Supplements should be started immediately after birth
xi) Iron deficiency can lead to problems with neurodevelopment which are reversed once treatment is started.
QUESTION 4
Which of the following are risk factors for NEC?
i) Early feeds
ii) Indomethacin
iii) Blood transfusion
iv) Fortified feeds
v) Thickened feeds
vi) H2 receptor antagonists.
QUESTION 5
Which of the following statements concerning feeds and feed supplements are correct?
i) All preterm formula fed infants should receive folic acid
ii) Infants with haemolytic anaemia should always receive folate supplementation
iii) Human milk contains sufficient vitamin A for the preterm infant
iv) Vitamin A supplementation is associated with a reduction in the incidence of chronic lung disease
v) All preterm infants should receive a minimum of 1000 IU vitamin D a day to prevent rickets
vi) Vitamin supplementation should be increased in hepatic failure
vii) Rickets can be prevented by adequate vitamin D supplementation
viii) Increasing calcium intake is usually helpful when there is evidence of poor bone mineralisation
ix) Nucleotide supplementation of formula milk may enhance growth in preterm infants
x) Human milk does not contain nucleotides
xi) Beta-carotene supplementation is of proven benefit in preterm babies
xiii) Vitamin E supplementation is useful in the prevention of haemolytic anaemia, ROP, BPD and IVH
xiv) Vitamin C levels in preterm infants are normally satisfactory and supplementation is not recommended
xv) The vitamin content of breast milk is affected by maternal diet.
QUESTION 6
You have admitted a baby to the neonatal unit who is 30 weeks gestation. The baby requires no respiratory support and her blood glucose is stable. The mother wants to breast feed and the practice on your unit is to give bolus feeds.
The mother wants to know why the baby cannot be fed continuously as she has heard about necrotising enterocolitis and is worried her baby may develop it if the baby is fed by bolus feeds. What do you tell her?
QUESTION 7
You review a 4-month-old baby in clinic who you have been treating for reflux with thickened feeds and erythromycin. The mother has been researching on the internet and thinks her child may actually be allergic to cows’ milk but then talks about protein intolerance.
i) Is this a plausible explanation for the symptoms?
ii) How do you explain the difference between CMA and CMPI?
iii) What is the prognosis for both conditions?
The mother wants her baby tested for cows’ milk allergy.
iv) What investigations do you carry out?
She wants to try soy milk as alternative milk. She has heard that it is good for the regurgitation and crying that her baby suffers with.
v) What do you tell her?
vi) Do you alter your treatment of the baby? If so, what do you do?
QUESTION 8
Which of the following are true?
i) Long-chain polyunsaturated fatty acids improve retinal sensitivity in preterm infants
ii) LCPUFA enriched formula milk can decrease the incidence of bronchopulmonary dysplasia
iii) LCPUFA enriched formula milk leads to a decrease in the incidence of sepsis
iv) A protein intake of above 3 g/kg/day is needed to support the same rate of growth as in utero for a preterm baby
vi) The addition of glutamine improves feeding tolerance in ELBW infants
vii) The addition of glutamine may decrease the incidence of infection in ELBW infants.
ANSWER 1
i)
a. pH probe study. This is a simple bedside test that gives reproducible data. Oesophagitis may be predictable and comparative data may be produced. However acid reflux only will be detected and there is evidence that up to 90% of GOR is due to milk or gas and is not acid. Normal values have only been established for term infants and cannot be applied to preterm infants. Furthermore the upper limit of acceptable reflux index (12%) is substantially higher than that regarded as acceptable in adults or older children (6%). Studies have shown poor correlation between pH probe reflux and symptoms. Infants should not be receiving antacids, H2 antagonists or proton pump inhibitors.
b. Oesophageal manometry. Allows assessment of motility and an understanding of the pathophysiology of GOR and of sphincter function. This tends to be used only in specialist centres as both operation and evaluation of results are complex. There is no role for this method in normal practice.
c. Oesophageal impedance. Allows detection of acid and non-acid events with an immediate result (in comparison to the delay with pH probe). Normal values are not available in either preterm or term infants and analysis is time consuming. As with pH probes there is poor correlation between episodes of reflux and symptoms. The predictive value for different treatments is not established.
d. Fluoroscopy. Allows visualisation of sucking and swallowing activity, structural anatomy and brief episodes of reflux. Studies are of short duration and episodes of reflux may be seen in normal and asymptomatic infants. It should not be used to evaluate the severity of reflux but has a role in the exclusion of other problems that may mimic reflux.
e. Endoscopy. Permits visualisation of areas of oesophagitis and biopsy if necessary. Requires considerable expertise particularly if biopsy is considered and especially in a preterm baby. An infant will require heavy sedation or anaesthesia.
f. Chiropractice. This has been recommended by several groups although evidence is lacking to support this therapy in this condition.
g. Empiric treatment. The commonest means of assessment. Not associated with the risk of other investigations but does carry a risk as does use of any medication. Effect is difficult to evaluate as a large placebo effect is associated with use of any medication in a condition associated with parental anxiety. Appropriate doses and associated risks are not clearly defined.
ii) There is a lack of evidence of efficacy and safety for all medications and none can be recommended routinely in the absence of evidence to suggest that GOR is the cause of symptoms. As several studies have failed to demonstrate such an association an argument could be made that none of these agents are appropriate. There are, however, specific considerations with some of these agents.
a. Cisapride. Prokinetic agent without central anti-dopamine effects which directly stimulate the myenteric plexus. In infants born under 36 weeks gestation, cisapride should not be used for up to 3 months, due to the risk of Q–T interval prolongation in this age group.
b. Gaviscon. A compound alginate preparation that forms a raft that floats on the surface of the stomach contents to reduce reflux. Contains sodium and magnesium alginate. Half sachet=1 dose=1 mmol Na.
c. Gripe water. A variety of products are marketed as ‘gripe water’ and all contain different ingredients – ginger, fennel, essential oils, peppermint, chamomile, caraway, aloe, lemon balm and activated charcoal just to name a few. All claim to bring immediate relief and many claim to be recommended by health care professionals. Supportive evidence is missing.
d. Antacids. Should not be used due to complications such as constipation (calcium- and aluminium-containing antacids), diarrhoea (magnesium-containing antacids), and metabolic bone disease (aluminium-containing antacids which bind to phosphate).
e. Thickeners. The number of reflux episodes may be decreased in term infants by adding a thickener to the milk to increase viscosity. In preterm babies or babies who are sick, thickened milk may lead to difficulties with sucking or swallowing. In these cases, simply increasing the concentration of the feed slightly may lead to less gastric distension, which in turn would decrease the likelihood of reflux, while maintaining calorie intake.
f. Hydrolysed formula. There is evidence that cows’ milk allergy can be indistinguishable from gastro-oesophageal reflux. Therefore, a trial of a hydrolysed formula (partially hydrolysed feed also known as semi-elemental, e.g. Nutramigen) may be beneficial in a baby who is showing symptoms of reflux and irritability. Improvement is usually seen within 1 week of changing the milk.
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