Transcript Neonatal and Infant Nutrition

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)
1. the process of taking in and assimilating
nutrients.
2. 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
‘Normal’ Nutrition
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
Breast is best
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
Normal output
Daily stool and urine output guidance
Day 0
1 wet nappy and meconium at least once a day
Day 1
2 wet nappies and meconium at least once a day
Day 2 & 3
3 or 4 wet nappies and changing stools at least once a day
Day 4+
5 or 6 heavy wet nappies and yellow stools at least once daily
A baby who is passing meconium at 3 or 4 days old may not be getting enough
milk.
A baby who does not have yellow stools by day 5 may not be getting enough
milk.
A baby who is not doing as many wet nappies each day as expected may not be
getting enough milk.
Support for breast feeding
mothers
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Midwife
Infant feeding specialist
Breast feeding support groups
National Childbirth Trust
Nutrition for the preterm or
sick baby
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
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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?
Normal doppler flow in umbilical
artery
Absent end diastolic flow
Reversed end-diastolic flow
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?
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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
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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
Preventing NEC: what works?
Strategy
Absolute RR
NNT
Enteral antibiotics
0.089
11
Judicious fluid administration
0.084
12
Human milk feeds
0.069
15
Enteral IgG and IgA
0.066
15
Enteral Probiotics
0.025
40
Antenatal corticosteroids
0.019
54
Delayed or slow feeding
Not effective
-
Enteral IgG only
Not effective
-
Feeding small or preterm infants:
Choices
• Human milk
– Mother’s own
– Banked donor milk
– Fortified
• Artificial
– Term formula
– Preterm formula
• Parenteral Nutrition
Parenteral Nutrition
Parenteral Nutrition
• If an infant can’t, won’t or shouldn’t be fed
enterally
• What’s in the bag?
–
–
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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
– Physical activity
– Specific dynamic action of food
– Thermoregulation
– Growth
(To match in-utero growth of 15g/kg/day)
40
4+
(10%)
variable
70
Protein
• With glucose infusion alone, infants lose 12% 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
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Line associated sepsis
Line related complications (eg thrombosis)
Hyperammonaemia
Hyperchloraemic acidosis
Cholestatic jaundice
Trace element deficiency
Milk Feeds
Human milk advantages
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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
Evidence Based Nutrition
• RA Ehrenkranz, Seminars in Perinatology 2007 (31): 48-55
Post-Discharge Nutrition
Post discharge nutrition
• Preterm infants tend to be small at
discharge, and remain small into
adolescence
• Limited evidence for what rate of growth is
optimal
The evidence
• Comparison of ‘post-discharge’ formula
with standard term formula
– No consistent difference in growth parameters
or body composition
– Z-score reduces in both groups
– Term formula needs supplementing with
vitamins and iron to achieve targets
The evidence
• Comparison of breast milk with term
formula
– Calcium and phosphate deficiency in breast
milk fed infants in first year resolves by age
two
– Little difference in growth (although small
numbers)
Outcomes
Catch-up Growth
• Enhanced nutritional intake sufficient to
allow ‘catch-up’ growth improves long term
neurodevelopmental outcome
Body composition differences
• Compared to term infants, ex-preterm
infants fed at 120 kcal/kg/day
– Have more body fat
– Have a different fat distribution
The long range forecast with
IUGR
• Does the in-utero environment or early
feeding permanently change organ
structure, function and metabolism?
Developmental Origins theory
• Humans demonstrate ‘developmental
plasticity’ in response to their environment
• Part of cardiovascular risk may be
explained by in-utero and postnatal growth
Developmental Origins theory
• Geographically, coronary heart disease
correlates with past neonatal mortality
• In epidemiological studies, adult
cardiovascular disease is associated with:
– low birthweight
– rapid early postnatal growth
Is rapid catch-up growth bad?
• Postnatal weight gain is associated with BMI and
waist circumference at 19 years
• IUGR infants are at increased risk of the
metabolic syndrome
• Preterm infants fed breast milk rather than
preterm formula
– had lower BP at 13-16yrs
– were less insulin resistant
– had a better LDL:HDL ratio
Nutrition Assessment
How best to assess growth and
nutrition?
• Weight
– Reflects mass of lean tissue, fat, intra- and extracellular fluid compartments
• Length
– More accurately reflects lean tissue mass
• Head circumference
– Correlates well with overall growth and developmental
achievement
Laboratory assessment
• TPN requires regular monitoring of acid
base status, liver function, bone profile
and electrolytes
• In enterally fed infants, monitoring
albumin, transferrin, total protein, urea,
alkaline phosphatase and phosphate may
be useful
Infant Feeding
Task
• Read the GP referral letter
• In pairs:
– Pick out the important aspects of the referral
– Decide what further questions you’d like to
ask the family
– What sort of investigations (if any) might you
consider?
Faltering Growth
‘Failure to Thrive’
• Term first used to describe delayed growth
and development,
– also called maternal deprivation syndrome.
• “A failure of expected growth and well
being”
• Only growth can be objectively measured
Crossing centiles?
• 5% of normal infants cross 2 intercentile
spaces from birth to 6 weeks.
• 5% of normal infants cross 2 intercentile
spaces from 6 weeks to 1 year.
• Infants regress to the mean
• Hence development of ‘thrive lines’
Causes and correlates
• Organic disease
• Abuse and Neglect
• Deprivation
• Undernutrition
Causes and correlates
• Organic disease
– <5%, usually suggestive symptoms and signs
• Abuse and Neglect
– increased risk, but a small proportion
• Deprivation
– may influence referral
• Undernutrition
The Energy Balance Equation
Undernutrition
• Most are underweight for height
• Fastest decline in weight gain when
energy needs are highest
• Poor appetite
• Delayed progression to solid foods
• Limited range of foods
Faltering Growth over time
Consequences
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Lasting deficit in growth
Lasting effects on appetite and feeding
Low maternal self esteem
Developmental delay at 1 year
– 7-10 DQ points
• Small (not statistically significant) IQ
difference at 8-9 years
Management
• Few trials of intervention
• One RCT found health visitor led
intervention useful
• One non randomised trial found dietary
advice useful
• Management is therefore based on
‘accepted best practice’
Screening or Case Finding?
• Up to 50% of children with FTT are never
identified
• Recommendations for frequency of
weighing suggest paying more attention to
fewer weights.
Growth Monitoring
Primary or Secondary care?
• Common problem, often resolves with
simple interventions
• Ill children or those losing weight need
referral
• Home visitor assessment
– Dietary history
– Simple explanation and advice
• Second port of call should be dietician
Strategies
The Role of the Paediatrician
• Investigations (if necessary) should be
completed promptly
• FBC, ferritin, U+Es, TFTs, TT glutaminase,
MSU
• Chromosome analysis in girls
• CXR and sweat test in young infants or
history of respiratory infections.
Pathway of care
If not improving?
• Nursery nurse involvement or nursery
placement
• Help with other behavioural problems
• Treat illness in mother
• Social work input
• Almost never need food supplements or
hospital admission
Task
• One volunteer to play the part of Neil’s
parent
• A second volunteer to be the registrar in
clinic
• Others to observe and be prepared to give
feedback at the end
Question
• What are the agendas of the health
professionals and the parent?
• How will you address the different
priorities?
• Where will you take things from here?
Feeding difficulties in ex-prems
• Feeding issues are common, especially in
those born before 28 weeks
• Risk of
– Disordered oral-motor functioning
– Significant gastro-oesophageal reflux
– Oral hypersensitivity
– Neurological impairment affecting feeding
Colic
What is Colic?
• “excessive bursts of crying in an otherwise
healthy infant not relieved by routine
comfort”
• ‘Colic’ crying is said to be of higher
amplitude, greater intensity, more frequent,
and of longer duration
Problems in Evaluation
• Poor case definition
• Few controlled studies
• Little evidence base for management or
investigation
The Classic Definition
• “crying lasting 3 or more hours per day, on
more than 3 days a week, for at least 3
weeks and resolving around 3 months”.
– Wassell, Pediatrics 1954
Study Results
• Quantifying colic
– scoring scales
– acoustic cry assessments
• No effect of sex, birth order, social class,
ethnic origin.
• Vagal tone and cortisol levels are the
same as in non-colicky babies
The impact on parents
• Resistance to soothing causes anxiety
• Learned helplessness, causing anxiety
and depression
• Stress can cause parental coping crises
• 10% of mothers experience a depressive
disorder postnatally
Temperament
• Some reports link excessive crying to later
difficult behaviours
– few studies only
– based on maternal recall
– possible that quality of care in later childhood
is influenced by early patterns of behaviour
Colic and difficulties with
feeding
• 19 with colic v 24 without
• Assessment:
– colic symptom checklist
– neonatal oral assessment score
– clinical feeding evaluation
Outcomes
• Colic group showed:
– more disorganised feeding behaviours,
– less rhythmic nutritive and non-nutritive
sucking,
– more discomfort during feeds,
– lower responsiveness during feeding
interactions.
• Miller-Loncar, Arch Dis Child 2004; 89 908-12
Organic causes of a ‘colicky’
baby
• congenital heart
disease
• CNS abnormalities
• NAI
• fever eg UTIs
• maternal drug
ingestion
• gastro-oesophageal
reflux
• cows milk protein
intolerance
• malabsorption
• gut dysmotility
Gut hormones
• Motilin initiates migrating motor complexes
• Vagus stimulation increases number and force of
contractions
• Raised motilin in 2 small studies of infantile colic
• Smokers have higher motilin levels
Systematic review of treatment
• Lucassen et al, BMJ, 1998
• 50 complete studies, 27 controlled
reviewed.
Treatments for colic
• Results as effect size
– Behavioural: (reducing stimulation) 0.48
– Dicycloverine: 0.46, but serious side effects
– Hydrolysate milks: 0.22
– Herbal tea: 0.32 (single small study)
– Low lactose and soya milks: no effect
– Simethicone: no effect
Treatments for colic
Any Questions?
Summary
• Optimal growth for neonates and infants
requires careful thought about nutrition
• Interventions (or lack of them) may have long
term consequences
• There is a limited evidence base to guide current
practice
• Colic is common
• Feeding difficulties post SCBU are common