Fetus and the Newborn

Question 1

Components of the APGAR score

Answer 1

1 - HR
2 - RR
3 - muscle tone
4 - reflex irritability
5 - color

Question 2

most objective measurement of intrapartum hypoxia-ischemia

Answer 2

presence of metabolic acidosis in umbilical arterial blood at time of birth (pH < 7.0 or BE > -12 is increased risk of neonatal neurological morbidity)

Question 3

appropriate eye prophylaxis for a newborn infant

Answer 3

erythromycin –> MC used to prevent opthalmia neonatorum from GC/Chlam; applies immediately after birth
- alternatives: silver nitrate (less effective, causes chemical conjunctivitis), povodone iodine (developing nations)

Question 4

RF for vitamin K deficient bleeding in infant

Answer 4

1. maternal drugs: antiepileptics, anti-TB, warfarin
2. exclusively breast fed
3. lack of prophylaxis at birth

Question 5

lab value most likely to be affected in vit K deficiency in newborn

Answer 5

prothrombin time

Question 6

types of vitamin K deficiency bleeding

Answer 6

1. early - first 24 hours; mother taking drugs during pregnancy
2. classic - 2 to 7 days; no vit K prophylaxis
3. late - 2 to 12 weeks; exclusively breast fed infants w/o prophylaxis, CF or celiac dz pts w/ inadequate vit K absorption

Question 7

presenting CF in classic vit K deficiency in newborn

Answer 7

bleeding from umbilicus, nares, venipuncture or circumcision site and/or GI tract; infant will appear ill or feed poorly
- CNS bleeding uncommon with classic form (but occurs in 50% of late onset disease)

Question 8

what studies do you do in any infant who presents with abnormal bleeding

Answer 8

PT, PTT, INR, fibrinogen, d-dimer and platelet count

Question 9

diagnosis: vit K deficiency

Answer 9

abnormal PTT

- confirm by administering vit K and documenting normalization of PTT and cessation of bleeding

Question 10

appropriate admin of vit K following birth

Answer 10

single parenteral dose
- oral may be substituted but must be given multiple times over first 2 months (preferred by some bc of study showing link between vit K shot and cancer)

Question 11

physiologic anemia of infancy

Answer 11

Hb prod decreased 10-fold by end of first week of life (increase in tissue oxygenation leads to decreased EPO prod) - leads to a nadir of Hb by 6-8 weeks of life in a full term infant; in healthy preterm infants, this nadir can be exagerrated

Question 12

physiologic anemia of prematurity

Answer 12

nadir in Hb is exagerated

- preterm infants weighing < 1500 g have an avg Hb of 8 g/dL at 4-8 weeks of life

Question 13

folate deficiency in a newborn - causes

Answer 13

1. severe maternal deficiency
2. congenital defects in metabolism, absorption or transport of folate
   - results in a macrocytic anemia

Question 14

iron deficiency in a preterm infant

Answer 14

normally, infants accumulate iron stores in third trimester of pregnancy; preterm infants are at risk of iron deficiency when they deplete their iron stores around 3-4 months of age

Question 15

differences in hyperbilirubinemia in a full term vs. late preterm infant

Answer 15

late preterm infants are at increased risk of severe hyperbili and kernicterus 2/2 decreased ability to process UCB due to decreased hepatic maturity reflected in ability to uptake bilirubin and conjugate it within the liver
– as a result, infants between 35 and 36+6 have lower bilirubin thresholds

Question 16

Major RF for Hyperbilirubinemia

Answer 16

1. Late preterm
2. isoimmune hemolytic disease
3. G6PD deficiency
4. sepsis
5. asphyxia
6. lethargy
7. temperature instability
8. acidosis
9. albumin < 3.0 mg/dL
10. exclusively breast fed infants w/ sig weight loss

Question 17

blood glucose goal level in a newborn infant

Answer 17

> 45 mg/dL before feedings in an asymptomatic infant

Question 18

tx. hypoglycemia in a newborn

Answer 18

if symptomatic and < 40 mg/dL –> IV glucose

Question 19

definition: polycythemia in a newborn

Answer 19

Htc > 65%

Question 20

Complications of polycythemia

Answer 20

1. Cardioresp: tachypnea, CHF, apnea, cyanosis
2. CNS: lethargy, tremors, seizures, stroke
3. GI: poor feeding, NEC
4. GU: renal failure, renal vein thrombosis, priapism
5. Heme: plethora, thrombocytopenia, DIC
6. Metabolic: hypoglycemia, hypocalcemia

Question 21

Tx. polycythemia

Answer 21

1. asymptomatic and Htc 60-70%: aggressive hydration and observation 24-48 hrs
2. symptomatic: partial volume exchange transfusion (replace calculated blood volume with normal saline) –> puts infant at risk of NEC (must consider in decision making)

Question 22

what should the mean blood pressure be in a newborn?

Answer 22

should be equal to or greater to gestational age in weeks

Question 23

tx. of hypotension in neonate 2/2 septic shock

Answer 23

dopamine - improves myocardial contractility and peripheral SVR

Question 24

preferred agents for volume resuscitation in hypovolemic shock

Answer 24

normal saline
PRBCs
lactated ringers solution

Question 25

volume resuscitation in infants weighing < 1500 g

Answer 25

should be avoided unless there is evidence of blood loss (ex. abruption, maternal-fetal transfusion or subgaleal hemorrhage) - otherwise, it increases the risk of CLD and IVH

Question 26

effect of prematurity on APGAR score

Answer 26

VLBW infants unlikely to have an APGAR > 6 because they are neurologically immature (hypotonia, decreased reflexes to noxious stimuli); A healthy premature infant may receive a low Apgar score without any other contributing factor other than prematurity because of decreased respiratory effort, muscle tone, and reflex irritability associated with physiologic immaturity

Question 27

oxygen toxicity in premature infants

Answer 27

1. retinopathy of prematurity: vasoconstriction of retinal vessels in response to O2 exposure causes of neovascularization
2. bronchopulmonary dysplasia: inflammation, fibrosis and abnormal pulm vascular development in response to oxygen toxicity

Question 28

guide for supplemental O2 administration in premature infants

Answer 28

maintain O2 sat between 85 and 95% at 10 min of life

Question 29

after initial resuscitation in a premature infant - what requires special attention?

Answer 29

1. blood glucose levels - low glycogen stores and impaired gluconeogenesis
2. temperature - decreased subcutaneous fat, thinner epidermis lead to increased heat loss
3. infection - broad spec abx and sepsis evaluation