Anatomic development of the GI tract
GI tract resembles the term infant at 20 weeks
Functional development of the GI tract
limited before 26 weeks
sucking movements occur at 13-15 weeks
functional suck, swallow, breath at 31-34 coordinated 36 week +
28 weeks limited functional capacity for digestion
Protein enzymes rise rapidly after birth
preterm infants have limited product
Lactate levels in the gut
pre-term infants have limited levels
reach mature levels at 36-40 weeks
other enzymes are functionally active at 28 weeks
Fat digestion
Begins in the stomach
gastric lipase is high at 25 weeks
peak at 35 weeks
Pancreatic Lipase
is less important in preterm infants than adults.
limited contribution to digestion in smaller earlier infants
GI motor function
limits the ability to move nutrients
AEB: lack of sucking coordination, decreased esophageal sphincter tone, delayed gastric emptying, and slow transit.
peristalsis and intestinal motility mature after 30-32 weeks but remain less organized until near term
Postnatal development of the GI tract
GI motility
main factor in providing eternal nutrition
Postnatal development of the GI tract
Diet
major factor in regulation of GI growth and function
oral nutrients can have direct or indirect effects
Vitamins ans minerals such as Zinc and iron are growth factors
Folic acid and B12 are necessary for DNA synthesis
Vitamin D influences calcium and Po4
Energy from fat
provides 9Kcal/g
is a major energy source
significant use occurs between 24-40 weeks
@24 weeks body fat is <2%
@32 weeks body fat is 5%
@40 weeks body fat is 15%
essential fatty acids are important for brain growth and malnutrition
Sources of fat for the newborn
release of free fatty acids from adipose tissue
absorption of fat from human milk or formula
50% of calories from fat
IV lipids
Energy from carbyhydrates
2nd major source of energy
human neonate brain is glucose dependent
brain accounts for 75% of glucose consumption
During the 3rd trimester excess glucose is stored as glycogen in the liver
Term infants and energy stores
the term infant has sufficient energy stores in the form of glycogen and fat for use during the relative starvation during the first days of life
Preterm infants and energy stores
have limited fat and glycogen stores and will quickly exaust energy stores.
nutritional support should start as soon as medically appropriate
Postnatal growth curves
weight, length and head circumference are based on gestational age
growth curves attempt to account early post-natal weight loss
represent slower growth velocity than seen on interuterine curves
definitive criteria is contriversial
Caloric and fluid requirements
Term infants
98/108 Kcal/kg/day
Adequate caloric intake 150-180 ml/kg/day of 20 Kcal formula
Protein, fat, and carbohydrate
Term neonates
protein 7-12%
Fat 35-55%
Carbs 35-55%
Vitamin supplements for
Term neonates
Vitamin D, iron and fluoride supplementation is recommended in breast fed infants
Human milk and term-infant formula
Term neonates
Human milk is the ideal formula
Should breast-feed for the first 12 months
Vitamin B12 supplementation for mom if she is vegetarian. 0.3-0.5 ug/day
Absorption of iron and zinc from human milk results in rare deficiencies even though contents in human milk
Iron Supplementation
Term neonates
may be beneficial in breast-fed infants beginning at 4 months
Vitamin D Supplementation
Term neonates
recommended for infants who are exclusively breast-fed
Fluoride supplementation
Term neonates
supplementation is recommended after 6 months
Nutritional requirements for preterm infants
Recommendations and advisable intakes mus be used
individual infants needs are highly variable
gestational age and weight influance stores and digestion
requirements are different for enteral and parenteral routes
Daily Nutritional requirements for preterm infants
Enteral
Enteral= by gut
Kcals 105-130
protein 3-4 G
Carbohydrates 10.8-16.8 G
Fat 5.4-7.2G
Daily Nutritional requirements for preterm infants
ParEnteral
ParEnteral= not by gut
20%< than enteral
Kcals 80-90
protein 2.7-3.8
Carbohydrates 6-12 G
Fat 0.5-3G
Daily water requirements for preterm infants
120-150 ml/kg/day
Factors that increase fluid requirements
abnormal fluid losses
diarrhea vomiting
increased activity
fever and cold stress
low environmental humidity
photo therapy
prematurity
radiant warmers
renal dysfunction
Factors that decrease fluid requirements
Hypoxic ischemic encephalopathy
BPD
PDA
CHF
Meningitis
renal failure
Assessing caloric intake
by appropriate daily weight gain.
10,-20 g/kg/day for preterm weight gain.
Factors that increase caloric requirements
Respiratory disease
fluctuations of ambient temperature outside of neutral
hypo/hyper-thermia
increased cardiac output. left-right shunting
increased muscular activity
Malabsorption
short gut
SGA
Protein intake
Necessary for cell growth
precise requirements not available
3-3.8 g/kg/day being 7-12% of intake
adequate protein intake is not achievable with unfortified human milk if the infant is fluid restricted
Whey-predominate formulas
better suited for pre-term formula
human milk has a 70:30 whey:cesin ratio
manufactured 60:30
Cow milk 18:82
Fat intake
major source of energy
4.5-6g/kg/g/d for enteral intake
medium-chain fats
are easier than long-chain fats
absorbed by passive diffusion and do not require bile salts
pre-term formula use a combination of medium and shoort fatty acids from vegetable oil
very-long chain fatty acids
associated with cognitive function and development
Vitamin A
supplementation with Va IM is associated with decreased BPD
Soy based formula
reccomended for infants with cows milk allergy, lactase deficiency or galactosemiaand for vegiterians
Not reccomended for thse <1800g
Pregestomil
alimentium
nurtamigen
for those with cows milk or soy allergies
gastrointestional or hepatobilary disease
Neocate & Elecare
cows milk allergy, short bowel, multiple food protein intolerance, sucrose, lactose, and galactose free
Lipids
10%: 1.1Kcal/ml
20%: 2.2Kcal/ml
for the prevention of deffiency of essential fatty acids
0.5-1 g/kg/D up to 3g/kg/D
20% preferred has lower phospholipid per gram of fat
Cholestatic Jaundice
prolonged periods without enteral feedings
hepatitis
GI surgery
Viral infections
Complications associated with fat administration
dry, scaly skin
poor growth
poor platelet aggregation
thrombocytopenia
vitamin deficiencies
contraindicated in infants with severe hyperbilirubenima
Measures to prevent or minimize complications with TPN
standardized policy/procedures
volume chamber with 4 hours of fluid
recorde intake and assess site Q1h
readjust as soon as complications arise
start enteral feeds as soon as possible
nothing added to TPN after it leaves pharmacy
filter fluids
wash hands
s
Tropic feeds
before 2 weeks of age
small volume stimulate growth and development of the GI tract
not used for nutrition but to encourage gut development
promotes gut development
stimulates intestinal motor activity
increases secretion of GI hormones
colonization of gu
Initiation of oral feedings
free of RDS <60 breaths per minute
demonstrated coordinated suck-swallow-breathe 32-34 weeks
assessment of behavioral ques
Kcals in D5w
0.15/ml
Kcals in D7.5w
0.25/ml
Kcals in D10w
0.34/ml
Kcals in D12.5w
0.43/ml
Kcals in D15w
0.51ml
Kcals in D17w
0.58/ml
Kcals in D20w
0.69/ml