Nutrition in the High-Risk Neonate

Armanian Amir Mohammad , MDNeonatologist

Assistant Professor of IsfahanFaculty of Medicine

• Currently, nearly all hospitilised infants

experience significant growth retardation during their stay in the NICU. (less than 1000 g)

• The fetus gains approximately at 16 weeks : 5 g/d at 21 weeks : 10 g/d at 29 weeks : 20 g/d at 37 weeks : 35 g/d

ENERGY REQUIREMENTS Energy Balance

• Energy balance = energy intake – (energy loss + storage).

• Energy loss = energy expenditure + excretion of energy (containing substances in urine and feces).

• If exogenous energy intake is less than expenditure, energy balance is negative, and body energy stores must be mobilized to meet ongoing needs.

FACTOR kcal/kg/d

Energy expenditure  Resting metabolic rate 40–60

  Activity 0–5

  Thermoregulation 0–5

  Synthesis/energy cost of growth 15

Energy stored 20–30

Energy excreted

15

Estimated total energy requirement

90–120

• Resting metabolic rate (RMR)

Preterm > term infants

• Nutritional requirements

Preterm > term infants In preterm infants receiving full enteral feeding, approximately 90% of

energy intake is absorbed.

The energy required for thermoregulation and activity can be

minimized by keeping the infant in a

thermo neutral environment and limiting stimulation.

Incubator

• The estimated RMR of infants with LBW is

lower immediately after birth than later

approximately 50 to 60 kcal/kg / day is

needed to maintain weight.

• Because neonates sleep 80% to 90% of the time , the energy

expended in physical activity is a smaller component of energy expenditure in neonates

than in adults.

• If the preterm infant is growing at the same rate as the fetus during the third trimester gaining approximately 15 g/kg/d.

…then about 15% of the total energy intake is used

for synthesis of new tissue.

• Most studies of enterally fed preterm infants receiving either human milk or formula report a higher rate of energy storage per gram of weight gain than that estimated for the fetus.

• The total daily energy requirements for full-term infants increase sharply from fetal levels during the first 48 hours of life and continue to increase at a lower rate until the end of the second week of life, reaching to 100 - 120 kcal/kg per day.

•Preterm infants have limited total body

energy stores, so providing adequate early

energy resources is more crucial for preterm

neonates than for full-term infants.

• ELBW : Higher weight-normalized nutrient intakes are necessary.

• Prenatal growth rate and body composition also may influence postnatal nutritional requirements.

• …have been shown, infants who are small for gestational age (SGA) may

require more nutrient intake per kilogram of body weight than larger infants.

• Individual infants vary in their activity, in their ease of achieving basal energy expenditure at thermoneutrality, and in their efficiency of nutrient absorption.

• Enteral intakes of 120 or 130 kcal/kg /day have been recommended, as this allows most

infants with LBW to grow at 15 to 20 g/d—growth rates similar to those achieved in utero.

• a target enteral energy intake of 130 to 140 kcal/kg per day may

be reasonable for infants with extremely low birthweights (ELBW) .

CARBOHYDRATE REQUIREMENTS

• Lactose is the predominant carbohydrate in human milk and

supplies 40% to 50% of the caloric content.

• Despite low lactase activities in premature infants, lactose is well tolerated by premature infants, and stable isotope data suggest efficient lactose digestion.

• Most Premature infant formulas include

Glucose polymers as a significant source of carbohydrate.

• Glucose polymers have the advantage of increased caloric density without a rise in osmolality, and they may also enhance gastric emptying.

PROTEIN REQUIREMENTS• The protein content and composition of human milk change

throughout lactation:

at birth : 2 g/dl to mature milk : 1 g/dl

• Qualitative changes also occur during lactation, resulting in a whey-to-casein ratio of 80:20 at the beginning of lactation, changing to 55:45 in mature milk.

• Indeed, whereas the levels of casein, α-lactalbumin, albumin, and lysozyme remain constant, the levels of secretory immunoglobulin A and lactoferrin decrease.

• For preterm infants with birthweights between 1200 and 1800 gr, the protein requirement is somewhere between 2.7 and 3.5 g/kg/d.

• Standard preterm formulas containing between 2.5 and 3 g of protein per 100 kcal can meet those requirements if fluid intake is not restricted.

• Infants weighing less than 1200 g may require more protein.

LIPID REQUIREMENTS

• Fat provides the major source of energy for growing preterm infants.

• Fatty acid absorption increases with decreasing chain length and with the degree of unsaturation, meaning that

medium-chain triglycerides (MCTs) with chain lengths of 6 to 12 carbons are hydrolyzed more readily than long-chain triglycerides (LCTs), and that fatty acids with more double bonds are absorbed more efficiently.

• Standard commercial formulas for healthy term infants do not contain MCTs, and human milk typically contains 8% to 12% of fat as MCTs.

• Unlike LCTs, MCTs are readily hydrolyzed in the gut, and the released fatty acids are transported across the gut barrier without the need for bile acids.

• MCTs are then transported directly to the liver via the portal vein as nonesterified fatty acids.

• In addition, MCTs can enter mitochondria and be oxidized without the need for carnitine-mediated transport through mitochondrial membranes.

• The total fat content of human milk increases postnatally.

• the percentage of cholesterol & phospholipids , both of which reside primarily in the milk fat globule membrane, decreases; in addition, the total

phospholipid content decreases as lactation progresses.

• The milk fat content and nutritional value of human milk vary with time.

• Its composition and energy content may vary in a pumping session and throughout lactation.

• Formula supplemented with docosahexaenoic acid (DHA) and arachidonic acid (AA) has produced positive changes in neurodevelopment measured in infancy in some studies.

• A minimum fat content of 4.4 g/ 100 kcal (40% of total energy) and a maximum of 6.4 g/ 100 kcal (57% of total energy) were recommended.

Formula

• Breast milk and even pooled breast milk cannot provide sufficient sodium, calcium, phosphorus, iron, vitamins B2, B6, C,

D, and E, and folic acid to meet the needs of infants with VLBW.

• Studies have shown that infants have higher rates of weight,

length, and head circumference increases when fed fortified preterm human milk than those fed only mature human milk.

ORAL VITAMIN REQUIREMENTS

• Vitamins are organic compounds that are essential for metabolic reactions but are not synthesized by the body.

• They are therefore needed in trace amounts from enteral or parenteral sources.

• Higher amounts of select vitamins are required by preterm infants, because they may have greater needs .

• Water-soluble vitamins (C , B ): Cannot be formed by precursors and do not

accumulate in the body (with the exception of vitamin B12). Therefore,

daily intake is required to prevent deficiency.

• Fat-soluble vitamins (K,E,D,A) :

They are important for the development and function of highly specialized tissues.

They can be built from precursors, are excreted with difficulty, and

accumulate in the body, and therefore they can produce toxicity.

They are not required daily, and deficiency states develop slowly.

• Vit. A : Higher intakes(1400 U/Kg) are considered safe and may

promote regenerative healing from lung injury, possibly reducing

the incidence and severity of CLD .

• Vit. D : 400 IU/d appears to be adequate for preterm infants.

• Vit. E : The recommended total intake of v.E is 3 to 4 IU/d for term infants. Recommendations

are somewhat higher for preterm infants.

• Vit. K : To prevent bleeding in the first week of life when enteral intakes are low is

recommended in the form of a 1-mg (IM) injection at birth in both term and preterm neonates > 1000 g birthweight.

Premature infants weighing < 1000 gr : 0.3 mg

Maintenance Na:

commencing at 48 to 72 hours : 2-4 meq/kg/d (ELBW: 3روز )

Maintenance K:

commencing at 48 to 72 hours :1-2 meq/kg/d وقتي ادرار خوب

برقرار شد

: هر چه پره مچورتر تر Immature , Na-k AT pase پمپ شیفت K داخل

سلول خارج به باالتر K سلولي

Minerals

Minerals• The peak of fetal accretion of minerals occurs primarily after 34 weeks’

and preterm infants fed low mineral intakes develop poorly mineralized bones.

• The advisable intakes range from 70 to 200 mg calcium per 100 kcal, 50 to 117 mg phosphorus per 100 kcal, and 6 to 12 mg magnesium per 100 kcal.

• Several studies have shown improvement of mineral retention or bone mineralization in preterm infants who receive higher calcium and phosphorus intakes .

...Minerals

• Consumption of unfortified human milk by infants

with VLBW after hospital discharge resulted in bone mineral deficits that persisted through 52 weeks postnatally, indicating the need for additional minerals after discharge.

• Supplemental bioavailable calcium and phosphorus salts may be required by breast-fed, preterm infants until their weight

reaches term weight (3 to 3.5 kg) .

...Minerals

• Preterm infants are at increased risk for the

development of iron deficiency anemia because:

• they deplete their stores from birth in half the time it takes a term infant to do so (at about 2 months of age).

• Infants with VLBW or sick neonates who are medically managed with

frequent blood sampling lose much of the iron present in the circulating hemoglobin, which is then unavailable for erythropoiesis.

Iron

• American Academy of Pediatrics (AAP) , agree on a recommendation of 2 to 3 mg/kg /d of dietary elemental iron, begun no later than 2 months of age in preterm infants and continued throughout the first year of life.

• Iron intakes of 2 mg/kg /d begun at 2 weeks of age were shown to safely augment ferritin stores in infants with LBW.

• Higher intakes : begun by 1 month of age and continued through age 12 months.

W < 1000 g : 4 mg/kg/day

W = 1000 - 1500 g : 3 mg/kg/ day weight at birth

W > 1500 g : 2 mg/kg/day

Iron

• Human milk is the optimal food for term infants because it provides immunologic and antibacterial factors, hormones, enzymes, and opioid peptides not present in alternative infant food sources.

• human milk is also the optimal primary nutritional source for premature infants.

• The strongest evidence of the benefit of human milk for premature infants is the reduced incidence of NEC.

• Other benefits include improved gastric emptying, reduced infections , and possibly better neurocognitive development.

Human Milk

• The milk from mothers of preterm infants contains more protein and electrolytes than does milk from mothers of term infants.

• These concentrations decline and approach the composition of term human milk in several weeks.

• Human milk does not completely meet the nutritional needs of premature infants; insufficient protein, calcium, phosphorus, sodium, zinc, vitamins, and possibly energy are provided by human milk to optimally support most premature infants.

Human Milk

• Human milk fortifiers (HMF) have been developed and tested and address many of these inadequacies .

• Premature infants fed fortified human milk may have growth

rates slightly lower than those of infants fed formula, but they may also achieve earlier discharge.

• HMF : W < 1500 gr : should be used W = 1500 – 2000 gr : should be considered

Human Milk

• Formulas for premature infants have been developed to meet the nutritional needs of growing preterm infants .

• Premature formulas contain a reduced amount of lactose ,because intestinal lactase activity may be low in premature infants.

• The remainder of the carbohydrate content is in the form of glucose polymers, which maintain low osmolality of the formula.

• The fat blends of preterm formulas are 20% to 50% MCTs, a level that is designed to compensate for low intestinal lipase and bile salts.

• The protein content of preterm formulas is higher than that of term formulas (2.7 to 3 g/100 kcal).

Preterm Formulas

• Specialized Formulas

• Preterm Discharge Formulas

• TERM INFANTS :• Supplementation for healthy, term,

breast-fed infants is usually not necessary .

(except for vitamin D,Iron)

• To prevent rickets, the AAP recommends that breast-fed infants receive

200 IU/d of vitamin D beginning during the first 2 months of life.

• Breast-fed infants usually require an additional iron source after 4 to 6 months of age.

Supplementation of Infant Feedings

PRETERM INFANTS :

• PRETERM INFANTS :• Daily multivitamin or mineral preparations may be

necessary for preterm infants once enteral feedings have been established.

• Multivitamin supplements that contain the equivalent of the

recommended daily allowances for term infants can be given.

• Liquid multivitamin drops do not contain folic acid because of its lack of stability, but it can be added or given separately.

Supplementation of Infant Feedings

• Breast-fed infants who weigh less than 3.5 kg do not consume enough human milk to acquire the recommended intakes of some vitamins and minerals.

• Supplementation with a multivitamin, folic acid, calcium, phosphorus, zinc, and iron may be necessary ,

• Unless one of the commercially available milk fortifiers is used.

Minimal enteral feeding

• Early feedings were begun at about 3 days of age and

consisted of human milk or formula

at 12 to 24 mL/kg/day..

• Minimal enteral feedings involve hypocaloric, low-volume enteral nutrition

that does not contain sufficient calories to sustain somatic growth.

• Proposed benefits include maturation of the preterm intestine

(both structurally and functionally), reduced liver dysfunction, and

improved feeding tolerance.• Without an increase in the incidence of NEC.

• Breast milk should be the first choice and

can be used undiluted..

• Diluting premature formulas for initial feedings is common clinical practice, but the data supporting this approach are limited.

• Infants achieved full enteral feedings and full nipple feedings earlier than did their counterparts who were fed sterile water.

• The available evidence strongly supports initiating early enteral feeding.

• Gavage feeding :

is appropriate for infants who demonstrate an immature suck and swallowing reflex or a clinical condition that is precludes nipple feeding , such as tachypnea or oral-facial anomalies.

• Therefore, most infants fed by gavage are GA < 34 Weaks.

METHODS OF FEEDING HIGH-RISK INFANTS

• Infants weighing > 2 kg have tolerated both orogastric (OGT) or nasogastric tube (NGT) placement without difficulty.

•Infants weighing < 2 kg Placement of an anchored orogastric tube

(OGT) is therefore recommended.

• with transition to NGT when the infant’s weight exceeds 2 kg.

Infants appear to tolerate feedings better if rapid gastric distention is avoided.

• bolus feedings over 20 to 25 minutes are generally recommended .

• Bolus feedings are usually delivered in equal volumes every 3 to 4 hours for term infants, every 3 hours for infants less than 2500 g, and every 2 to 3 hours for infants less than 1500 g.

• Gastric emptying may be a clinical problem but is enhanced with

human milk feedings and when infants are in the prone or right-sided position.

A number of retrospective studies suggest that

rapid advancement of feedings

(greater than 25 cc/kg per day) may increase the risk of NEC.

• Continuous drip feedings :

• colonization of expressed milk is universal, and

logarithmic growth of bacteria occurs in milk left at room temperature for more than 6 hours.

• Another disadvantage of continuous drip breast milk feedings is the

potential loss of nutrient delivery (up to 34% of the expressed milk fat).

METHODS OF FEEDING HIGH-RISK INFANTS

• The mother’s milk supply is directly related to the

response of prolactin and oxytocin to breast stimulation.

• Because a preterm infant often cannot be placed at the breast,

mechanical pumping is frequently elected.

• Emptying the breasts with the pump should

be attempted 8 to 10 times daily.• If a double collection kit is used, pumping

takes approximately 10 minutes.

Establishing Lactation

• Freshly expressed milk can be fed to infants immediately, which is the preferred method of delivery.

• If milk is refrigerated, it should be discarded 24 to 48 hours after collection.

• Milk that is frozen should be thawed by running it under tepid water until it is room temperature. A microwave should not be used for thawing, to ensure maximum preservation of the host defenses.

• All thawed milk left over from a feeding should be discarded.

Early Breast-Feeding Experiences

• (KMC) It is suggested that early skin-to-skin contact between mothers and their preterm infants is advantageous for a variety of reasons.

• Infants born as young as 32 - 34 weeks’ gestation have demonstrated the

ability to coordinate sucking with swallowing and breathing when offered a breast feeding.

• These same infants, when bottle fed (PO) , showed difficulty with respiratory control and frequently demonstrated “cyanotic attacks.”

• Oral feedings are usually offered once daily, with supplementation by

orogastric tube, until the infant reaches the equivalent of 34 weeks’ gestation.

Early Breast-Feeding Experiences

• The clinician should listen for sounds of swallowing during feeding and point them out to the mother, because infant feeding noises are highly reinforcing.

• First feeding experiences often involve only one breast and

may be brief.

• A successful feeding is one that both the infant and the mother enjoy, and it should not be measured by the volume consumed.

• The volume will rise as the mother’s and infant’s performances improve over time.

• It is difficult to clinically assess the volume suckled at a feeding.• The weight difference in grams estimates the milliliters consumed.

Early Breast-Feeding Experiences

• Routine mechanical expression can be reduced

• when the infant feeds vigorously

• Nurses from both breasts at each feeding

• And is gaining weight steadily (15 to 40 g/d).

Early Breast-Feeding Experiences

• Parenteral nutrition (TPN) should begin early and continue until full enteral feedings are reached.

• parenteral nutrition should also be reinitiated without delay when enteral feedings are interrupted.

• As parenteral nutrition is being provided and advanced, minimal early enteral intake for the infant with extremely low birthweight should be strongly considered, beginning at day 2 or 3 of life.

PRACTICAL APPROACH

• The requirement for mechanical ventilation or the presence of an

umbilical arterial line (UAC) should not prevent initiating minimal enteral feeding.

• Breast milk from the infant’s mother is the preferred enteral substrate; it is usually provided undiluted and

ultimately fortified with a standard Human milk fortifier (HMF) when the infant has achieved full-volume feeds.

PRACTICAL APPROACH

Small aliquots of human milk or premature formula may be provided by the OGT on a regular intermittent schedule

(1 to 2 cc/kg every 2 to 3 hours)

PRACTICAL APPROACH

• One common approach is to advance feedings by 20 cc/kg /day if the infant tolerated the previous 24 hours of feeding

this typically results in full enteral feeding (150 cc/kg/day) in 7 to 10 days.

• More recent data suggest that prolonging small feeding volumes for a

period of time may reduce NEC. Some period (5 to 10 days) of small enteral feedings (20 cc/g/day) should be considered before advancing, especially in the high-risk

population of infants with ELBW.

PRACTICAL APPROACH

• Throughout the process of advancing feeds, adjustments are made if signs and symptoms of feeding intolerance are

observed (e.g., residuals, abdominal distention, blood in stools, increased respiratory distress).

Best Rigards…