Neonate: Transition to Extrauterine Life

The Term Neonate

• A neonate is a newborn baby during the first 4 weeks.

Adaptations to Transitioning to Extrauterine Life

Circulation

• Placental blood flow ceases.
• Pulmonary vascular resistance diminishes, while systemic blood pressure elevates.
• Blood becomes oxygenated in the lungs.
• Shunt from foramen ovale (from right to left atria of the heart) and ductus arteriosus (blood vessel connecting pulmonary artery to descending aorta) closes within the first couple days of life, with the DA closing in the first hour.

Respiration

• Fetal lung fluid gets expelled, and intrathoracic pressure decreases.
• Air flows into the lungs, which causes alveoli to expand.
• Surfactants get released to lower surface tension.

Metabolism

• Thermoregulation occurs.
  • Rapid heat loss from large SA, weight, thin skin.
• Glucose regulation is important.
  • There's a high risk of hypoglycemia, which is increased in prematurity, gestational diabetes, SGA.

Renal

• The first voided urine happens within 24 hours of life.

GI

• Meconium is passed within 24-48 hours of life.

Risk Factors for Needing Support for Transition

Antepartum

• Preterm labor may occur.
• Maternal infection may be present.
• PET or maternal HTN can cause issues.
• Multiple pregnancy increases the risk.
• Diabetes may cause harm.
• PROM/PPROM can occur.
• A known fetal abnormality may be present.

Intrapartum

• Precipitous labor is fast is high risk.
• Prolonged labor can cause issues.
• Malpresentation of the baby can occur.
• Cord prolapse is dangerous.
• Maternal analgesia affects the baby.
• Instrumental delivery affects the baby.
• Emergency CS can cause issues.

Routine Care for Healthy Full Term Baby

• Place the baby skin to skin with mother.
• Clamping of the umbilical cord happens Vitamin K IM injection gets administered to prevent vitamin K Deficiency bleeding.
  • Early administration is preferable, first 24 hours. Can cause I.C.H.. Is serious. If mom is on anticoagulants, anticonvulsants, TB treatment, administer the medication via syringe.
  • Classic administration is between 1-7 days, and can increase severity of GI bleeding, ICH, bruising, bleeding after circumcision.
    • Absence of Vit K prophylaxis increases the risk.
    • Factors include no IM Vit K, exclusive breastfeeding, poor intake of milk.
  • Late administration happens between 2-12 weeks up to 6 mo.
    • ICH is caused by exclusive breastfeeding, only 1 dose or no vit K, disease interfering with vit K absorption
• Newborns often have low vit K storage due to poor placental transfer, insufficient endogenous production from intestinal bacterial flora, inadequate intake if exclusively breast fed
• Feeding also increases risk of hypoglycaemia
• Transfer to postnatal ward happens after exams
• First neonatal exam - APGAR: Scores happen at 1 min and 5 mins.
  • Appearance:
    • 2 points: Pink
    • 1 point: Extremities blue
    • 0 points: Pale or blue
  • Pulse:
    • 2 points: >100 bpm
    • 1 point: <100 bpm
    • 0 points: No pulse
  • Grimace:
    • 2 points: Cries and pulls away
    • 1 point: Grimaces or weak cry
    • 0 points: No response to stimulation
  • Activity:
    • 2 points: Active movement
    • 1 point: Arms, legs flexed
    • 0 points: No movement
  • Respiration:
    • 2 points: Strong cry
    • 1 point: Slow, irregular
    • 0 points: No breathing

Neonatal Resuscitation

• Dry and stimulate the baby with a towel and hats.
• Ensure thermoregulation, radiant warmer, plastic bag, heated gel mattress.
• Clean airways, suction if secretions, blood or amniotic fluid (meconium) is present
• Provide positive pressure ventilation (CPAP/PPV) as required.
• Provide respiratory or further support if needed.

Normal Growth Parameters

• Weight:
  • Low: <2.5 kg
  • Average: 3.5 kg
  • High: >4.5 kg
• OFC (occipital frontal circumference):
  • Low: <33 cm
  • Average: 35 cm
  • High: <37 cm
• Length:
  • Low: <48 cm
  • Average: 50 cm
  • High: >52 cm
• OFC assesses for micro/macrocephaly
  • Microcephaly is <2th centile, macrocephaly is >98th centile
• There's an assessment of birth weight.
  • LBW is <2.5 kg, VLBW is (<1.5 kg), ELBW is (<1 kg)
  • SGA is <10th centile, AGA is 10-90th centile, LGA:>90th centile

Respiratory Disorders

• Respiratory distress is more common in preterm babies with antenatal, perinatal, and postnatal factors, usually below 32 weeks.
• Recognize distress signs early as respiratory failure and cardiopulmonary arrest can escalate quickly.
• Surfactant production typically begins around 24-28 weeks gestation.

Signs of Respiratory Distress

• Pallor or cyanosis is present.
• Tachypnea indicates compensation for hypercapnia & hypoxemia, the respiratory cardiac or sepsis/metabolic
• Stridor is an unusual sound.
• Grunting indicates the baby is attempting to generate PEEP.
• Nasal flaring is present.
• Tracheal tug is present.
• Intercostal/subcostal retractions are present.

History Taking (Risk Factors)

• Antenatal factors:
  • Anomaly scans show congenital pulmonary/renal malformation.
  • Oligohydramnios means there is an inability for lung to properly develop.
  • Polyhydramnios causes a metabolic condition.
  • Poorly controlled GDM: hyperglycemia risk/ toxic to lungs.
  • GBS carrier / active infection in mum
  • Antenatal Steroids increase lung maturity, 2x >24h pre-delivery
• Perinatal factors:
  • PROM/PPROM = infection risk
  • Mode of delivery: CS increased risk of TTN
  • Term vs Preterm:
    • Term = unlikely RDS, more likely TTN/MAS
    • Preterm = RDS, CLD, infection
  • Flat at delivery? Sign of distress
  • Meconium at delivery?

DDx

Common

• Sepsis: commonest cause of neonatal death. Treatment is take 3 and give 3.
• TTN: transient tachypnoea of the newborn Passes after 24h, Baby trying to force amniotic fluid out of alveoli. Usually CPAP for few hours, some baby might be tired & decompensated.
• RDS: respiratory distress syndrome cause a higher risk of death
• PPHTN: persistent pulmonary HTN of the newborn High pulmonary pressure in utero means there's an active PVA causing a risk of fluid into interstitial spaces and back pressure, which might cause cardiac compromise and a vasodilator required, with T21 having a higher risk
• MAS: Meconium Aspiration Syndrome

Less Common

• Pulmonary Hypoplasia is often caused by CDH Congenital Heart Disease can be present

Ix

• Congenital Diaphragmatic Hernia (CDH) is a situation where the usually left lung is affected, depending on level of herniation surgery might not be possible, can cause PNX
• Bilateral Choanal Atresia is when there's a blocked nasal passage
• Pneumonia (PNA) is more apparent,
• PNX can be mild from aspiration and mainly requiring pigtail drain Haemo Disorders: SCD, thalassemia
• Metabolic Disorders occur.
• Biochem: includes analyzing the FBC, U&E, CRP, ABG, blood cultures.
• Imaging: includes CXR, ECHO.

Acute mx

• ABCDEs must be implemented
• Respiratory support must be offered as needed
  • Supplemental O2 can be administered via nasal cannula/incubator/free flow.
  • Non-invasive ventilation is recommended via CPAP 1st line
  • Invasive ventilation needs endotracheal tube & ventilation
• Administer abx (antibiotics) while awaiting result if suspect injection
• Patient Hx should involve antenatal & birth hx, swallow/aspiration/asthma

Prematurity: RDS, BPD, bacterial PNA (?), PNX

• TTN: a Delayed reabsorption of lung fluid, the Cx is because pt is a Term infant CS, the Sx is because Tachypnoea ↑WOB, the Dx and Mx is because Monitor O2 sats, RR, WOB, ARB, the baby gets IV fluid/NG if tachypnea and CPAP/O2 if required. If necessary, the CXR to r/o other pathology.

• RDS: there's a Surfactant deficiency -> alveolar collapse & inadequate gas exchange, because the Px has a prematurity and the diabetic mother. Because Surfactants are and Sx: is Tachypnoea ↑WOB Hypoxia, the management involves determining whether you need IV abx or steroids. The baby may have to be put on CPAP and endotracheal NIV.

• Definitions and causes:

  • TTN: there's a Delayed reabsorption of lung fluid, cx because they are a Term infant, the precipitate delivery and diabetic mom, the Sx: shows Tachypnoea,↑WOB, and Grunting.

• RDS: there's a surfactant deficiency.

Neonatal Sepsis

Causes

• GBS (Early: septicemia, RDS, Late: septicemia, meningitis)
• E. coli (preterm) (septicemia/meningitis):
• Listeria monocytogenes (flu like illness in preg) (Early onset: meconium-stained amniotic fluid) nosocomial infections
• H.Influenzae, Klebsiella, Pseudomonas Pneumococci
• Early onset Sepsis
• First 72 hours of life
  • Characterized by sudden onset and fulminant course
  • Typically the organism is acquired from the maternal genital tract. Ascending infection with chorioamnionitis
    • GBS and Ecoli most common
• Late onset
  • Usually more insidious
  • Breaks in the natural barrier function of the intestine and the skin allow opportunistic organisms to invade -Esp premature infants
• RFs for vertically acquires NS\
  • PROM, maternal pyrexia, suspicion of chorioamnionitis, premature labour, mother GBS+ or previous invasive GBS disease, inadequate or no IAP- intrapartum antibiotic prophylaxis (inadequate if <4 hours prior to delivery, do not always prevent neonatal sepsis)
    RFS for nosocomial sepsis
  • premature, LBW, neutropenia, indwelling catheters, surgery Signs + Syx

temperature instability behaviour

Nutritional requirements of a newborn baby

• Initial weight loss is normal (<10%)
• Most babies regain weight by day 5, but may take up to 2 weeks
• Double in weight by 6 months
• Need 100kcal/kg per day to grow

Skin to skin: why?

• Breathing + HR (positive impact on cardiorespiratory stability)
• Blood glucose (= temperature regulation)
• Bonding (oxytocin release)
• Bacteria (acquisition of the microbiome)
• Breastfeeding - more likely to initiate and maintain breastfeeding Don't dry hands - because have amniotic fluid, and have the same scent as the nipple?
  • Baby will taste hand and go for the nipple
• Good because it shows baby's ability to root and latch coordination and sensory engagement

Production of breastmilk

Breast anatomy

• Glandular tissue - ~20 lobules
  • Lobe contains:
    • Alveoli (produce milk)
    • Lactiferous tubules (small ducts and connect alveoli) Milk ducts (extend from tubules and open onto the nipple)

Lactogenesis

• Lactogenesis I = After 16wks, lactation occurs, colostrum accumulates and alveoli become distended
• Lactogenesis II = Triggered by placental expulsion, falling progesterone and oestrogen levels and presence of prolactin
  • Placenta remnants can decrease affect breastmilk production
• Colostrum (2-4 days) → Transitional milk (4 days -2 weeks)→ Mature breastmilk