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Flashcards in Congenital Heart Defects Deck (77)
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For the fetus the placenta is

the oxygenator so the lungs do no work


RV & LV contribute equally to

the systemic circulation and pump against similar resistance


Ductus venosus allows

oxygenated blood to bypass the liver


Foramen ovale

R→L atrial level shunt; shunt that bypasses the lungs, It moves blood from the right atrium of the heart to the left atrium


Ductus arteriosus

R→L arterial level shunt;

The ductus arteriosus moves blood from the pulmonary artery to the aorta; it allows most of the blood from the right ventricle to bypass the fetus's fluid-filled non-functioning lungs


In a right to left shunt, blood __________

(that hasn’t traveled to lungs yet) is shunting across to the left side of the heart

-Oxygen and nutrients from the mother's blood are transferred across the placenta to the fetus.
-Goal of fetal circulation is to get oxygenated blood to brain


PDA allows blood to go into aorta and into ________

vessels of head and neck (getting blood to brain)


Normal PaO2 in umbilical vein of fetus

30-35 mmHg.


Residue 143

-Single amino acid change of histidine to serine

-Histidine positively charged; Serine neutral

-This change results in LESS binding of 2,3 BPG to fetal Hb which INCREASES fetal oxygen affinity
*Baby has higher affinity for oxygen from moms blood due to single amino acid change


With the first few breaths after baby is born, lungs expand and serve as oxygenator. Placenta is removed from the circuit, systemic pressure _________, pulmonary pressure _________

systemic INCREASES
pulmonary DECREASES (so blood can flow to lungs)

-Foramen oval functionally closes
-Ductus arteriosus closes within first 2-3 days


After baby is born, pressure is higher

in L atrium than R atrium, 1 way valve is closed and flow from R to L stops

-shunts close in first 45 seconds of life


Neonates with CHD often rely on _______

a patent ductus arteriosus and/or foramen ovale to sustain life

-The ductus normally closes by 3 days
-The foramen ovale normally closes by 3 months


What function does the PDA provide after birth in a baby with cyanotic congential heart disease?

Provides a source of pulmonary blood flow


In the presence of hypoxia or acidosis (present in ductal-dependent lesions), _____________

the ductus may remain open for a longer period of time

-As a result, these patients can present to the ED as late as the first 2 weeks of life (Sepsis is usually #1 on differential, congenital heart disease is #2

*Start antibiotics and PGE (to keep PDA open)*


S/S of venous congestion

Right side: Hepatomegaly, Ascitis, Pleural effusion, Edema

Left side: *Tachypnea, Retractions, Crepitations
Pulmonary edema


S/S of lower cardiac output

Acutely: Pallor, *Sweating
Cool extremities, increased capillary refill time, Tachycardia

Chronic: *Feeding difficulty, *Fatigue, Poor growth


Neonatal EKG findings

-Highest peak in limb leads (RVH is NORMAL)
-Normal finding bc R vent was dominant when it was inside mom, takes a while for L vent to bulk up and get bigger
-eventually L vent will have stiffer more muscular will and RV will be more compliant chamber


Chromosomal causes of CHD

-Down Syndrome: up to 50% will have defects
-VACTERL, CHARGE Association: 50 - 85% will have defects (involve many body systems)


Maternal illness that causes CHD

-Pre-Gestational Diabetes: 50% increase risk (if diabetes is poorly controlled; vent septal defect, transposition of great arteries, coarctation of aorta)

-Lupus: complete heart block (Abs from mom cross placenta and attack conduction system in baby’s heart; monitor baby heart via EKG)
-Infection (Viral): rubella in 1st 7 wks = Patent Ductus Arteriosus


Maternal substance abuse and CHD

-Severe FAS (EtOH) = 50% have CHD


Down syndrome associations

AV canal and VSD


Turner syndrome associations

Coarctation of aorta


Trisomy 13 (Patau syndrome) and 18 (Edwards syndrome)



Fetal alcohol syndrome associations

L--> R shunts and metrology of fallot


CHARGE syndrome

conotruncal lesions (ToF, truncus arteriousus)


Pulse ox on arm and leg and difference in more than 10% saturation= ________

(R upper arm sat 100%; Lower extremities O2 sat is LOWER)

differential cyanosis

*lower limbs are cyanosed but the upper limbs are not

-will see increased precordial activity and displaced PMI


Differential cyanosis is from

PDA with R to L shunt or
CoA with PDA after constriction


S/S of Pulmonary cyanosis

-baby is grunting, struggling to breathe
-tachypnea, distress, retractions with breathing
-cyanosis may improve with crying
-may heart rales, crackles or wheezing in lungs
-normal heart sounds/cardiac silhouette
-CXR shows ground glass, pneumonia, atelectasis, pneumothorax
-normal EKG
-pCO2 increased usually
-PROFOUND response to 100% O2


S/S of Cardiac cyanosis

-baby is blue, but breathing fine (comfortable)
-cyanosis worsens when baby cries
-hear cardiac murmur
-cardiomegaly/abnormal shape or position of heart
-normal lung fields, may see some decreased vascularity or pulmonary vascular congestion
-EKG shows abnormal rhythm
-pCO2 is normal to low
-NO response to 100% O2


Differential pulses, weak in LE, think