The Newborn

Question 0

Placental circulation is (low/high) resistance, (low/high) flow circulation.

Answer 0

Low resistance; high flow

Question 1

Fetal circulation is (low/high) PO2 and (low/high) demand.

Answer 1

Low PO2 (22-25mmHg in aorta) and low demand (low thermoregulation need and low respiratory work)

Fetal Hgb has a higher oxygen carrying capacity.

Question 2

Four reasons why fetuses have high pulmonary vascular resistance.

Answer 2

Fluid filled alveoli
Compression of capillaries
Active vasoconstriction
Thick media

High pulmonary vascular resistance but LOW systemic vascular resistance.

Question 3

Name three fetal shunts.

Answer 3

Foramen ovale
Ductus arteriosus
Ductus venosus

Question 4

Two mechanisms that help elicit the first breath

Answer 4

Placental hypoperfusion (asphyxia of labour)
Cold stress

Question 5

What happens to PVR, SVR and shunts after delivery

Answer 5

PVR decreases => alveolar expansion, increased blood oxygen content, increased pH, increased pulmonary blood flow 8-10 fold
SVR increases => increase in blood oxygen content, loss of placental vascular bed
Shunts close…..hopefully.

Question 6

Common causes of abnormal cardiorespiratory transition

Answer 6

Transient tachypnea of the newborn
Respiratory distress syndrome
Persistent pulmonary hypertension of the newborn
Neurological disorders (delayed onset of spontaneous breathing)
Asphyxia
Sepsis

Question 7

APGAR scores are taken at which two time periods after birth?

Answer 7

1 minute and 5 minutes

Question 8

What are the components of the APGAR score?

Answer 8

Out of 10 (5 categories; each category is out of 2)
Heart rate (absent, <100 BPM, 100 BPM or more)
Respirations (absent, weak cry, strong cry)
Muscle tone (limp, some flexion, active motion)
Reflex irritability (no response, grimace, cough or sneeze)
Colour (blue/pale, extremities blue, completely normal-coloured)

Question 9

What does routine care of a newborn entail?

Answer 9

Bonding and early breastfeeding
vitamin K => to prevent hemorrhagic disease of the newborn
Ocular prophylaxis => prevent ophthalmia neonatorum, chlamydia, gono
Cord care => when does it fall?
HBV prophylaxis => normally we vaccinate in 4th grade, give prophylaxis if mother high risk

Question 10

Neonatal cold stress leads to……

Answer 10

Surge in post-natal catecholamines and TSH surges
Activates heat production, gluconeogenesis and glycogenolysis
BUT can lead to cardiovascular compromise

Question 11

How do newborns maintain their temperature?

Answer 11

Non-shivering thermogenesis => oxidation of brown adipose tissue (decreases gradually in first year of life)
Voluntary muscle activity and shivering NOT usually involved…

Question 12

How to prevent heat loss in a new born?

Answer 12

Dry and remove wet linens
Provide heat source such as the MOTHER or FATHER!
Other heat sources such as room temp, lamp, radiant warmer, blankets, warm water bottle, incubator etc,

Question 13

Risk factors for neonatal hypoglycemia

Answer 13

Decreased glucose products in preterm babies, hypoxia, cold stress, sepsis
Hyperinsulinism in infants of diabetic mothers, Rh incompatibility, Beckwith-Wiedemann syndrome

Question 14

Symptomatic hypoglycemia may present as…….. (12)

Answer 14

Abnormal cry, apathy, apnea, cardiac arrest, convulsions, cyanosis, hypothermia, hypotonia, jitteriness, lethargy, tremors, tachypnea.

Question 15

Neonatal hypoglycemia is most often (symptomatic/asymptomatic) and its symptoms are (specific/non-specific).

Answer 15

Asymptomatic; non-specific

Question 16

The biggest danger in neonatal hypoglycemia

Answer 16

Neuronal damage!

Question 17

IV treatment for hypoglycemia required if …….

Answer 17

Blood glucose <2.6mmol/L despite feeding or if symptomatic

Otherwise, treatment consists of: early feeding, PO supplements, give anti-insulin drug (ex. Diazoxide)

Question 18

Routine blood glucose screening in which two newborn populations?

Answer 18

Infants of diabetic mothers (first 12 hours)
SGA infants (first 36 hours)

Question 19

Causes of physiological jaundice (4)

Answer 19

1. Increase synthesis of bilirubin (shorter lifespan of RBCs, higher hematocrit, degradation of erythrocyte precursors)
2. Increased intestinal bilirubin absorption
3. Relative deficiency of hepatic bilirubin transport/uptake mechanisms
4. Deficiency of the conjugation mechanism (glucuronyl transferase) which allows unconjugated bilirubin to become conjugated and therefore water soluble and excreted in the bile.

Question 20

How does physiological jaundice typically present?

Answer 20

Indirect hyperbilirubinemia
Usually appears of 2-3rd day of life
NEVER <24 hours of life
Cephalo-caudal progression

Question 21

DDx neonatal jaundice

Answer 21

Hemolysis (immune vs.non-immune)
Congenital (ex. gilbert syndrome)
GI obstruction
Hypothyroidism

Question 22

In jaundice, beware of…..

Answer 22

Bilirubin encephalopathy (clinical syndrome) and kernicterus!
Neuronal death and pigment deposited in basal ganglia
Mortality 4-50%

Question 23

Management of neonatal jaundice

Answer 23

Phototherapy
Exchange-transfusion
Rhogam prophylaxis for Rh negative mothers

Question 24

Discharge guidance for new parents

Answer 24

Weight => neonates will lose 10% but should regain it by 10 days
Should have their first urine in first 24 hours, first stool within 48 hours
Should sleep on their back
Should always be in a car seat facing the back (for less than 9kg)
Metabolic screening should be done: TSH, PKU, tyrosinemia
Arrange for an early follow up