Neonatology 1

Question 1

What are the significant development times of the heart of a foetus?

Answer 1

• Begins to develop toward the end of the third week.
• Heart starts to beat at the beginning of the fourth week.
• The critical period of heart development is from day 20 to day 50 after fertilization.

Question 2

Describe the foetal circulation

Answer 2

○ Oxygenated blood via umbilical vein – Ductus Venosus.
- Foetal blood vessel connecting the umbilical vein to the IVC
- Blood flow regulated via sphincter
- Carries mostly oxygenated blood
○ Some blood via Foramen Ovale to Left Atrium – Left Ventricle – Aorta (Ao).
○ Some of blood to Right Ventricle – Pulmonary Artery (PA) - Patent Ductus Arteriosus (PDA) from PA to Ao.
○ Saturation SaO2 in foetal body is 60-70%.
○ Ductus arteriosus
- Protects lungs against circulatory overload
- Allows the right ventricle to strengthen
- Carries low oxygen saturated blood

Question 3

What is the normal blood pressure of a newborn at 1 hour, 1 day and 3 days?

Answer 3

• 1hr: 70/44
• 1 day: 70(+/-9)/42(+/-12)
• 3 days: 77(+/-12)/49(+/-10)

Question 4

What is the normal respiratory signs in a newborn?

Answer 4

• 30-60
• Periodical breathing
• Difficult to assess if spontaneous breathing.
  □ Research rather clinical devices
• Non-invasive:
  □ Blood gas determination
  □ PaCO2 5-6 kPa, PaO2 8-12 kPa
  □ Trans-cutaneous pCO2/O2 measurement
• Invasive:
  □ Capnography
  □ Tidal volume 4-6 ml/kg
  □ Minute ventilation:
  ® Tidal Volume ml/kg x respiratory rate
  □ Flow-volume loop

Question 5

What is the normal heart rate of a newborn?

Answer 5

120-160bpm

Question 6

What counts as tachycardia and bradycardia in a newborn?

Answer 6

• Tachycardia
  □ >160bpm
• Bradycardia
  □ <100bpm

Question 7

How does a newborn thermoregulate?

Answer 7

• Maternal thermoregulation in the womb.
• New born babies lack shivering thermo genesis thus need a metabolic production of the heat.
• Brown fat well innervated by sympathetic neurons.
• Cold stress leads to lipolysis and heat production.

Question 8

Where does a newborn loose heat?

Answer 8

- Radiation:
□ Heat dissipated to colder objects.
- Convection:
□ Heat loss by moving air.
- Evaporation:
□ We are born in the water.
- Conduction:
□ Heat loss to surface on which baby lies

Question 9

Describe fluid balance in a newborn (full term)

Answer 9

• Full term infant is able to maintain fluid / electrolyte balance
• Weight loss up to 10% is normal
• Loss is due to:
  □ Shift of interstitial fluid to intravascular compartment
  □ Diuresis
• It is normal not to pass urine for the first 24 hrs!

Question 10

Descibe fluid balance in pre-term infants

Answer 10

• Less fat in body composition
• Increased loss through kidney:
  □ Slower GFR
  □ Reduced Na reabsorption
  □ Decreased ability to concentrate or dilute urine
• Increased Insensible Water Loss (IWL)
  □ Via immature skin and breathing
  □ Physiological IWL is 20-40 ml/kg/day but could be up to 82 ml/kg/day in 750-1000 g

Question 11

Why might a baby be small for its gestational age?

Answer 11

- Maternal
□ Smoking
□ Drinking
□ Pre-eclampsia toxaemia 
- Foetal
□ Chromosomal e.g. Edward's syndrome (trisomy 18)
□ Infection e.g. CMV
- Placental
□ Placental abruption
- Other 
□ Twin pregnancies

Question 12

What are the common problems presentated by a infant who is small for gestational age?

Answer 12

□ Perinatal hypoxia
□ Hypoglycaemia 
□ Hypothermia 
□ Polycythaemia 
□ Thrombocytopaenia 
□ Gastrointestinal problems (feed, NEC)
□ RDS, infection

Question 13

What are the long term problems in newborns who are small for gestational age?

Answer 13

□ Hypertension
□ Reduced growth
□ Obesity
□ Ischaemic heart disease

Question 14

What counts as preterm and extremely preterm babies?

Answer 14

○ Preterm <37 weeks

○ Extremely preterm <28 weeks

Question 15

What counts as low birth weight and very low birth weight in newborns?

Answer 15

○ Low weight <2500g

○ Very low birth weight <1500g

Question 16

What are the common prolems in preterm babies?

Answer 16

○ Respiratory distress syndrome (RDS)
○ BPD (Broncho-pulmonary dysplasia)/ CLD (chronic lung disease) 
○ Minor respiratory problems
○ Intra-ventricular haemorrhage (IVH)
○ Peri-ventricular leukomalacia (PVL)
○ Post haemorrhagic hydrocephalus (PHH)
○ Necrotising enterocolitis  (NEC)
○ Persistent ductus arteriosus (PDA)
○ Retinopathy of prematurity (ROP)
○ Neonatal abstinence syndrome (NAS) 
○ Hypoxic-ischemic encephalopathy (HIE)

Question 17

How is respiratory destress syndrome managed?

Answer 17

□ Prevention
® Antenatal steroids
□ Early treatment 
® Surfactant 
® Then as little as possible 
◊ Early extubation 
◊ Non-invasive support (N-CPAP)
◊ Minimal ventilation (low tidal volume and good inflation)

Question 18

Talk about BPD (Broncho-pulmonary dysplasia)/ CLD (chronic lung disease)

Answer 18

□ Overstretch by volu-baro-trauma  
□ Atelectasis- collapse of the lung  
□ Infection via ETT
□ O2 toxicity 
□ Inflammatory changes 
□ Tissue repair- scarring
□ Treatment
® Patience 
® Nutrition and growth
® Steroids

Question 19

What minor respiratory problems happen in premature babies and how are they managed?

Answer 19

□ Apnoea/ irregular breathing/ desaturations
□ Treatment
® double expresso (caffeine)
® N-CPAP

Question 20

Talk about intraventricular haemorrhage and the premature baby

Answer 20

□ Most common limiting factor for good long term prognosis
□ Grades I-IV
□ Under 28 weeks fairly common
□ Not so common 28-37 weeks
□ Bleed happens in the first 3 days of life
□ Prevention: AN steroids
□ Treatment
® Symptomatic
® Drainage
□ On the 21st day of life macrophages come up and clean the dead tissues

Question 21

Talk about peri-ventricular leukomalacia in premature babies

Answer 21

□ 95% adverse outcome
□ Not dangerous immediately but then starts pushing the tissue
® The brain is pushed becoming thinner and thinner
□ Outcome
® No new production of neurons
® They will wither have paraplegia or quadriplegia

Question 22

How is post haemorrhagic hydrocephalus treated in premature babies?

Answer 22

BP shunt

Question 23

Talk about patent ductus arteriosus in premature babies

Answer 23

□ Pressure in the left side of the heart is higher
□ You flood the lungs from left to right
□ The lungs overflow with blood which steals blood from the peripherals and causes ischaemia
® Worry about the gut and kidney
® Lung oedema
□ Additional blood to pulmonary circulation
® Overperfusion of the lungs
® Lung oedema
□ Steal from systemic circulation
® Systemic ischaemia
□ Consequences
® Worsening of respiratory symptoms
® Retention of fluids (low renal perfusion)
® Gastrointestinal problems (GE ischaemia)

Question 24

Talk about necrotising entro-colitis in premature babies

Answer 24

□ Bubbles that are lined up are pneumatosis
□ You see oedema which means they are already retaining fluid
□ Ischaemia and inflammatory changes
□ Necrosis of the bowel
□ Surgical intervention is often required
□ Conservative management is sometimes possible
® Antibiotics
® Parenteral nutrition

Question 25

Talk about nutrition in premature babies

Answer 25

• Enormous nutritional requirements unparalleled
• Patients often triple their size during hospital stay
• Building new functional tissues from compounds provided artificially

Question 26

What are the ourcomes of extreme prematurity?

Answer 26

• Unpredictable at the time of birth
• Ultrasound of brain by the end of the 1st week
• Often very uncertain even on discharge home
• Surprising deterioration (cognitive and behavioural) between 2nd and 6th year
• Also some unexpected improvement between 2nd and 6th year of life
• Extremely limited data on subjective quality of life in adulthood

Question 27

What fraction of premature babies:

• Die
• Have a normal life or mild disability
• Have severe or moderate disability?

Answer 27

• 1/3 dies
• 1/3 have normal life or mild disability
• 1/3 have severe or moderate disability