Neonatal Exam

Question 1

umbilical v.

Answer 1

• Baby receives O2 blood from umbilical v, through the umbilical cord. the Umbilical v. dumps blood into the IVC, which joins with the SVC to provide blood into the RA.

Question 2

alveoli filled with fluid causes?

Answer 2

• The lungs alveoli are filled with amniotic fluid, and thus have very high pressure and low O2 levels. The alveolar sacs due to low O2 make the arteriole constrict and the resistance is greatly increased in the arterioles throughout the lungs. Thus both pulmonary aa. face high resistance = “hypoxic pulmonary vasoconstriction” → b/c pulmonary aa. are facing a large amount of resistance, the pressure is high in pulmonary aa, thus pressure is high in right ventricle, thus pressure is high in the right atrium. → due to high blood pressure on right side, the blood takes shortcuts to get to the left side of heart

Question 3

foramen ovale

Answer 3

Septum primum is on left side, septum secundum is on the right side (there are two walls next to each other, separating right and left atrium). septum secundum has a small hole through it (called foramen ovale). Septum prmum also has a break in the wall. When pressure is high in RA, it pushes on septum primum flap, causing the foramen ovale to be an opening allowing RA blood to flow into the LA. Thus, When blood is pumped into RA, it flows to LA, to LV and is pumped throughout the fetal circulation

Question 4

ductus arteriosus

Answer 4

Not all blood goes through foramen ovale, but some goes through RA tricuspid valve into RV, where it pumps into left and right pulmonary a. Fetal heart has a vessel connecting the aorta and the pulmonary artery, and blood passes the lungs (all but 10%)

Question 5

ductus venosus

Answer 5

allows blood to go from umbilical vein, through the vein where it meets up with IVC, allows blood to bypass capillaries of liver. IVC and SVC dump into the RA.

Question 6

five circulatory adaptations before birth/

Answer 6

1. umbilical vein (carries O2 to fetus)
2. Ductus venosus: shortcut from umbilical v. to the IVC (through the liver)
3. Foramen Ovale (shunt from right atrium to left atrium)
4. Ductus arteriosus: (allows blood to go from pulmonary artery to aorta) – from high pressure → lower pressure: this explains why you don’t have a large amount of blood coming back from pulmonary veins
   → blood goes from aorta to the internal iliac artery → umbilical artery
5. Umbilical Artery: brings blood back to placenta from the internal iliac artery (allows for oxygenation of blood). The placenta has a VERY low resistance, thus the blood wants to flow to the placenta

Question 7

timing of fetal circulation changes after birth?

Answer 7

1. umbilicalvv - days
2. ductus venosus - days
3. foramen ovale- closes in first few minutes
4. ductus arteriosus: hours
5. umbilical aa - close in hours

Question 8

why does foramen ovale close after birth?

Answer 8

closes due to decreased RA/RV pressure, and increased LA/LV pressures

Question 9

why does ductus arteriosus close?

Answer 9

constriction of smooth mm. in walls due to high O2 levels and decreased prostaglandin levels, causing it to be closed, keeping blood from being shunted from pulmonary aa. to aorta. (smooth mm. constrict)

Question 10

why does umbilical aa. close after birth?

Answer 10

umbilical aa. are branches off of internal iliac a. , resistance is high because of the clamp and no blood wants to go in this direction. also these aa. have smooth mm → constriction of umbilical aa.

Question 11

what happens when umbilical clamp is placed?

Answer 11

When umbilical clamp is placed on the cord, the Warton’s Jelly is compressed. The wharton’s jelly starts to contract around the umbilical aa. and vv. when the temperature falls (in the delivery area). This contaction results in a great increased pressure, thus shunting blood away from the placental arteries and veins.
As a result of high resistance, no blood flows through umbilical v, and ductus venosus, and it becomes unused and begins to clot. Deoxygenated blood fills into the right atrium and right ventricle and is squeezed into pulmonary arteries from the right ventricle. Initially in the lungs, the alveoli are full of fluid, which is now replaced by air, pushes fluid out. The areteriole vasodilates due to the increased oxygen levels in the alveoli. When the arteriole dilates, the resistance falls in the capillaries in the lungs, resulting in increased blood flow in the pulmonary arteries, and allows for blood to get into the lungs. → resistance of lungs is decreased → resistance in RV to decrease → resistance in RA to decrease
Oxygenated blood from pulmonary veins dumps into left atrium, and the pressures on right side have fallen → foramen ovale to close. blood is then squeezed into the aorta.  

Question 12

steps of babies own breathing? steps of clamping?

Answer 12

baby breathes in air –> pushes fluid out of alveoli –> arterioles vasodilate due to increased O2 levels in alveoli –> decreased resistance in capillaries of lungs –> increased blood flow in pulmonary aa –> decreased lung resistance –> decreased RV resistance, decreased RA resistance –> O2 blood dumps into LA, and pressure increases –> foramen ovale to close –> blood squeezed into aorta

When clamp is placed/Wharton’s Jelly at RT –> umbillcal aa/v pressure increased –> shunting of blood away from placenta –> due to high resistance, no blood flows through umbilical v. and ductus venosus –> becomes clotted

Question 13

babies breathing rate

Answer 13

30-60 bpm

Question 14

when should uneven shape of babies head go away?

Answer 14

2-3 days after birth

Question 15

acrocyanosis

Answer 15

persistent blue or cyanotic discoloration of the extremities, most commonly occurring in the hands, although it also occurs in the feet (not of huge significance and will go away)

Question 16

central cyanosis

Answer 16

the whole body is cyanotic, this is problematic and means that O2 needs to be given to the baby

Question 17

Harlequin skin

Answer 17

unilateral flushed side of thorax, unknown etiology, not of serious consequence

Question 18

newborn vitals

Answer 18

• Temperature 36.5-37.5° C
• Respirations 30-60 breaths/minute
• Heart rate 100-160 beats/minute

Question 19

caput succedaneum

Answer 19

tissue edema above the periosteum which crosses suture lines – this is not a huge emergency, because it should just reabsorb, but if it is large enough you should worry about hyperbilirubinemia due to blood break down

Question 20

cephalohematoma

Answer 20

bleeding and fluid under the periosteum that occurs in about 2.5% of births. It does NOT cross suture lines

If severe the child may develop jaundice, anemia or hypotension. In some cases it may be an indication of a linear skull fracture or be at risk of an infection leading to osteomyelitis or meningitis.

The swelling of a cephalohematoma takes weeks to resolve as the blood clot is slowly absorbed from the periphery towards the centre.

Question 21

ductus arteriosus patency maintained by?

Answer 21

patency is maintained by prostacyclin I2

• Falling of PGE2 levels when placenta is cut, causes closing of ductus by 15 hours of age
• increased pulmonary vascular resitsance can cause right to elft shunting through ductus esp. with hypoxia of the newborn

Question 22

glucose transitions

Answer 22

• During the third trimester fetal glucose levels are approximately 80% of maternal levels
• The fetus does not synthesize glucose under normal resting conditions
• After birth gluconeogenesis and glycogenolysis must maintain blood glucose levels
• Glycogenolysis begins around the end of the 3rd trimester
Note: lethargic, seizing baby – neonatal seizures can be very subtle, flickering of eyes or smacking of lips = result of hypoglycemia,

Question 23

choanal atresia

Answer 23

failure of communication b/w nose and pharynx
• infants will have difficulty breathing and cyclic cyanosis (The infant initially attempts to breathe through the nose, and is unable to; hypercapnia occurs, and many babies instinctively begin to cry. While crying, oral ventilation occurs and cyanosis subsides. There is variation in the length of time until a baby begins oral breathing, and some will never cease attempts at nasal breathing.)
• can check for patency in nares by passing a small feeding tube into each nostril

Question 24

leukocoria

Answer 24

white pupillary reflex

Question 25

epstein peals

Answer 25

whitish-yellow cysts that form on the gums and roof of the mouth in a newborn baby. NO tx is necessary, they will disappear in 1-2 weeks of birth

Question 26

crepitus

Answer 26

grating /crackling/popping – heard when two fragments of fracture are moved against one another

Question 27

meconium in umbilical cord

Answer 27

meconium stained umbilical cord = suggestive of stressed baby in utero, and amniotic fluid containing meconium – could result in meconium in the lungs. This baby will need direct resuscitation.

Question 28

umbilical hernias

Answer 28

mostly asymp. and will regress on their own

Question 29

spina bifida occulta

Answer 29

most mild spina bifida, occurs when some vertebrae is not completely closed. the spinal cord does not protrude, but skin may be dimpled or covered with hair

Question 30

meningocele

Answer 30

least common form of spina bifida, where vertebrae don’t develop normally and meninges go b/w the gaps. The NS remains undamaged, and there are unlikely to be serious health problems, though it could be associated with a syndrome.

Question 31

myelomeningocele

Answer 31

most severe spina bifida that contains both meninges and spinal cord – usually results in spinal cord defect and some sort of paralysis

Question 32

sacral dimple

Answer 32

: usually ok, however need to be sure that no fistula is present, and sometimes MRIs are ordered to see the extent of the dimple

Question 33

butterfly mark

Answer 33

Congenital midline vascular lesions above the sacrum – raise the possibility of underlying defects (such as occult spinal dysraphism) and may need to be investigated further.

Question 34

occult spinal dysraphism

Answer 34

tethered spinal cord syndrome – a group of neurological disorders relating to the pulling of the spinal cord at the base of the spinal canal – which leads to progressive damage if not properly treated.

Question 35

Barlow and Ortlani test

Answer 35

• Barlow test: adduct hip (bring thigh towards midline) while applying light pressure on the knee, directing the force posteriorly
• Ortolani test: move out to relocate the hip that has been displaced by the Barlow maneuver: flex hips and kneesand place anterior pressure on greater trochanters and gently and smoothly abduct the legs using thumbs

Question 36

different hypospadias?

Answer 36

= displaced urethra
o Subcoronal: The opening of the urethra is located somewhere near the head of the penis.
o Midshaft: The opening of the urethra is located along the shaft of the penis.
o Penoscrotal: The opening of the urethra is located where the penis and scrotum meet.