Neonatal Transition and Nutrition

Powerpoint presentation

Neonatal transitional physiology 

Role of placenta:

•Nutrient, electrolytes, vitamins, water and oxygen/gaz exchange

•Waste removal: CO2, bilirubin, etc.

•Hormone production and regulation (steroid / thyroid pathway; PGE)

•Oxydative, immune and fetal (physical barrier) protection + immune tolerance

•Neurodevelopmental maturation: muscular tone, proprioception, protection from ambient noise/light/excessive stimulation (filters appropriate level for maturation). Effect of gravity and progressive constriction of womb on neuro-muscular programming.

•Synthesis of enzymes and other substances

•Hemoglobin production

•More!

Fetal-Placental Physiology

After birth

Transition of the newborn

• 85% of newborns transition successfully to extrauterine life without assistance.

• 10% will begin breathing in response to drying and stimulation.

• 5% of newborns will require PPV to support their breathing.

• 2% of term newborns will need intubation for respiratory support.

• <1% of newborns will receive chest compressions and emergency medication.

• Need for assistance cannot always be predicted, requiring health care providers to be prepared to respond quickly and efficiently when necessary.

• Clearance of fetal lung fluid with active sodium absorption and changes in airway pressure

• Lung expansion

• Surfactant secretion, and breathing

• Transition of fetal to neonatal circulation

  • Decrease in pulmonary vascular resistance and increased pulmonary blood flow

  • Delayed cord clamping supports an increase in blood volume and Hgb/Iron reserve

  • Increased SVR with separation from the low-resistance placental vasculature

  • Closure of ductus venosus

  • Closure of PFO / PDA

  • Rapid lowering of PVR with lung expansion (parachute) onset of ventilation / oxygen exposure

• Endocrine support of the transition

• Increased metabolic rate leading to higher glucose needs

• Increased catecholamine levels to support blood pressure 

Risk of abnormal transition and Neonatal Resuscitation

NRP 8th Edition Algorithm

MRSOPA

NRP medications

APGAR Score

Neonatal definitions

Classification by birth weight:

•Low birth weight (LBW) < 2,500 g

•Very low birth weight (VLBW) < 1,500 g

•Extremely low birth weight (ELBW) < 1,000 g

•Particularly “micro” premature infant < 750 g

Sub-categories of preterm birth are based on gestational age

•Extremely preterm <28 weeks

•22 to 25+6 weeks: sub-category most at risk regarding transition, nutrition, morbidities, etc.

•Very preterm: 28 to <32 weeks

•Moderate to late preterm: 32 to <37 weeks

Prematurity – general risks

• Hypoglycemia

• Temperature instability and difficulty regulating body temperature

• Respiratory Distress Syndrome or other disordered transition of the respiratory system (TTN, pneumothorax)

• Apnea and bradycardias

• Hyperbilirubinemia

• Anemia

• Feeding difficulties and poor weight gain

In the most immature infants: (<28 weeks):

•Intraventricular Hemorrhage (bleeding in the brain)

•Necrotizing Enterocolitis

•Retinopathy of Prematurity

•Sepsis (infection)

•Developmental delays

Modified Ballard Score and Neonatal Physical Exam

Oxygen Saturation

Hypoxic Ischemic Encephalopathy and Therapeutic Hypothermia (Abnormal Transition)

•HIE / Abnormal transition often with failure of fetal circulatory adaptation to extrauterine life, causing constriction of pulmonary arteries à PPHN

•PPHN primary or secondary to meconium aspiration, RDS, infection, depressed transition (maternal-placental), cord accident, etc.

•Clinical Presentation: Cyanosis, labored breathing, and respiratory distress shortly after birth

•Diagnosis: Confirmed through echocardiography showing increased pulmonary artery pressure and right-to-left shunting

•Immediate Treatment: Essential, involves supplemental oxygen and addressing underlying causes

•Prognosis: Variable, depending on the severity and promptness of intervention

•Multidisciplinary Approach: Requires collaboration among neonatologists, pediatric cardiologists, and respiratory therapists

PPHN - Persistent Pulmonary Hypertension of the newborn (Acute PH)

Management of PPHN

•Ensure appropriate ventilation, but avoid hypocapnia (cerebral vasoconstriction)

•Sedation/Analgesia may be indicated to avoid reactive increase in PVR

•Oxygen should be administered to aim 90-95% pre-ductal saturation

•Due to right to left shunt, there is a threshold at which FiO2 increase has no impact and excessive O2 may cause lung injury by reactive oxygen species

•iNO is one of the only agent studied in RCT for PPHN in the term and near-term newborns

•Treatment of seizure (which may induce PH crisis – reactivity of pulmonary vascular bed)

•In neonatal PPHN – bicarbonate not recommended: intracellular acidification may worsen the situation

•No evidence that paralyzing agents provide benefits and may worsen = not recommended as continuous infusion, but consider as bolus

•Consider hydrocortisone supplementation if concerns of relative adrenal insufficiency or adrenal ischemia

•Inotropic + vasoactive support

•ECMO (VV / VA if cardiac dysfunction).

PPHN guidelines mention:

•iNO indicated to reduce ECMO need (OI > 25)

•Lung recruitment should be performed if associated parenchymal lung disease (ex: meconium aspiration)

•Some may benefit from PGE if RV failure to unload RV and sustain systemic output (no RCT)

Neonatal Nutrition Basics

Classification by size - reflect the in utero nutritional status of the infant:

•Appropriate for gestational age (AGA): 10-90th percentile.

•Small for gestational age (SGA): <10th percentile. ?Placental dysfunction, ?CMV/TORCH, ?Genetic, etc.

•Large for gestational age (LGA): >90th percentile. ?Diabetes, ?Genetic.

Intra-Uterine Growth Restriction (IUGR): Susceptible to fetal depression / intolerance to labour.

•Fetus does not achieve its expected growth potential during pregnancy (often resulting in a birth weight <10th percentile)

•Example: falling off trajectory during pregnancy.

•Asymmetric: Head sparing.

•Symmetric: entire body is proportionally small – either extremely severe placental dysfunction (prolonged), or other etiology that requires investigation.

Extra-Uterine Growth Restriction (EUGR):

•Falling of trajectory on growth curve

•Weight < 10th percentile at discharge.

Why Nutrition is important in the NICU

•Critically ill neonates face complex medical problems: compromised nutrition

•Illnesses, treatments (e.g: diuretic, steroid), low nutrient stores, organ immaturity, adverse GI condition can hinder provision of adequate calories and nutrients.

•(gastroschisis, short bowel syndrome, inflammatory GI conditions, intestinal hypoperfusion, hypomotility, obstruction, etc.)

•Nutrition and fluid management differ during transition and subsequent stabilization. Requirements varying based on

•Infant's weight, gestational age

•Metabolic demand/expenditure, In/Out fluid status (renal/liver conditions), tendency in weight gain (weight/length ratio trajectory

Nutritional Requirements:

•Vary by GA: premature with nutrient usually greater nutrient needs

•SGA: higher basal metabolic rate

•Metabolic status (high vs low demand) influence nutrient needs

•Therapeutic hypothermia comatose mechanically ventilated may have less demand than 25 week GA on CPAP with fast respiratory rate

Growth Assessment in the NICU

•Expected initial weight loss of < 10% due to contraction of extracellular compartment.

•Birth weight usually regained by 2 weeks.

•Healthy newborns have lowest weight at day 3-4 and regain within 7-10 days

•Subsequent weight gain based on normal intrauterine rates: 10-20 g/d < 27 weeks GA and 20-30 g/d for infants 27-40 weeks GA.

•Weight gain can also be expressed for preterm as 10-20 g/kg/d.

•More accurate when calculated over 4-7 days.

•Crown-heel length incremental gain is 0.8-1.1 cm/week for preterm infants and 0.7-0.75 cm/week for term infants.

•Head circumference gain is 0.1-0.6 cm/week for preterm infants and 0.5 cm/week for term infants.

Fenton preterm growth charts

Resources from University of Calgary on Fenton Growth Charts and Calculators

WHO Growth Charts

Dieticians of Canada WHO portal

Energy and Protein

•Maximal protein gain occurs prior to 32 weeks gestation

•Parenteral energy needs are slightly lower than enteral requirements (10-15% less) since there are no absorptive or digestive losses

•Energy needs are increased in cardiac failure, severe respiratory distress, BPD, severe sepsis and following major surgery.

•Energy distribution should be 40-50% energy from both carbohydrate and fat and 10-15% from protein.

•Fat should never make up greater than 60% of total energy to avoid ketosis.

Enteral:

Breastmilk = the best  = the golden treatment for all babies Pasteurized human milk only to complement if needed, or while waiting for milk production to be sufficient. 

• PHM to be considered eligible for prematurity, GI conditions, CHD. 

• Rare contraindications (e.g. galactosemia, HIV+, active untreated TB, active HSV on both breast nipples, maternal use of cocaine, maternal radioactive isotope treatment).

• Breastfeeding resources here

Feeding approaches and progression - Example of a protocol

Fortification

Quick Reference of Nutrient Content by Milk and Fortification

Total Fluid Intake, intravenous support and parenteral nutrition

<29 weeks and/or <1000g in the first 72 hours after delivery:

• Birth weight ≤ 750 gm: 100 ml/kg/day

• Birth weight > 750 gm: 80 ml/kg/day

• Consider increasing total fluid intake by 10-20 ml/kg if

• Significant weight loss

• Urine output exceeds hourly rate for more than 4-6 hours or Serum sodium is increasing.

• Aim for serum Na 135-145 mmol/L. Avoid serum Na > 150

• Avoid Na in IV fluids (except for UAC) for the first 24 hours.

34 weeks to term : start on day 1 with 65 mL/kg/day 

29 weeks to 34 weeks: start with 80 mL/kg/day 

Progress of 20 mL/kg/day every day (based on clinical status and progression; urine output and weight; Na levels). Usually reaching a maximum of 150 to 160 mL/kg/day.

•Premature: RDS, intestinal hypomotility, limiting ability to feed enterally. Or complications: instability, NEC, post-OR, etc.

•Larger neonates with respiratory, GI, cardiac, or post-surgery, may require PN temporarily.

•Early PN introduction is metabolically safe and prevents negative nitrogen balance, benefiting protein kinetics.

•Protein content in PN may prevent fluid shifts by keeping fluids intravascularly.

Long-term PN complications include:

•Hepatobiliary issues, like cholestasis.

•Metabolic bone disease and osteopenia, particularly in preterm infants.

•Incidence increases if kept NPO

•Consider introducing small amounts of trophic feeds whenever possible for gut priming to reduce the risk of complications.

Progression of TPN content by days

Fluid content as per AAP