Ch. 421 - The Fetal to Neonatal Circulatory Transition Flashcards Preview

Nelson - Exam 5 (Cardio/Hema/Onco) > Ch. 421 - The Fetal to Neonatal Circulatory Transition > Flashcards

Flashcards in Ch. 421 - The Fetal to Neonatal Circulatory Transition Deck (30)
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1

3 cardiovascular fetal structures important for maintaining a parallel circulation

1) Ductus venosus 2) Foramen ovale 3) Ductus arteriosus

2

Highest level of O2 provided to the fetus comes from

Umbilical vein

3

% umbilical venous blood that enters the hepatic circulation

50%

4

Flap of tissue at the right atrial-inferior vena cava junction

Eustachian valve

5

Blood from the IVC in the fetus is preferentially routed to

The foramen ovale to the left atrium

6

Major source of LV blood flow in the fetal circulation

Blood from the RA rather than the pulmonary vein

7

PO2 of SVC blood

12-14mmHg

8

Blood from the SVC to the RA preferentially flows to the

Tricuspid valve into the RV

9

Only approx ___% of RV outflow enters the lungs

5

10

Majority of RV outlfow enters the ___

Ductus arteriosus into the desending aorta

11

Total fetal cardiac output

~450ml/kg/min

12

Approximately ___% of descending aortic blood flow returns to the placenta while the remaining perfuses fetal organs and tissues

65

13

RV output in the human fetus is ___x that of the LV flow

1.3

14

T/F During fetal life, the RV is performing a greater volume of work than the LV

T

15

Leads to rapid decrease in pulmonary resistance at birth

Mechanical expansion of the lungs and increase in arterial pO2

16

Increase in systemic vascular resistance at birth is brought about by this event

Removal of low-resistance placental circulation

17

Reversal of flow at the ductus arteriosus from right to left to left to right is due to

Increase in systemic circulatory pressure and decrease in pulmonary circulatory pressure

18

Brings about closure of the DA

High arterial pO2

19

Remnant of the DA

Ligamentum arteriosum

20

Event that leads to closure of the DV

Removal of the placenta from the circulation

21

Systemic cardiac output at birth

~350ml/kg/min

22

Medications that may be given to maintain the DA open and close respectively

PGE1 or E2, indomethacin

23

Largest decline in pulmonary resistance from the fetal to adult levels in the human infant at sea level occurs within

2-3 days, but may be prolonged for 7 days or more

24

Factors that lead to constriction of the neonatal pulmonary vasculature

1) Acidosis 2) Hypercapnia 3) Hypoxemia

25

Normal adult cardiac output

75ml/kg/min

26

The foramen ovale is functionally closed by

3rd month of life

27

The DA is functionally closed by

10-15 hrs of life

28

In a full term neonate, ___ is the most important factor controlling ductal closure

O2

29

When the pO2 of the blood passing through the ductus reaches about ___mmHg, ductal walls begin to constrict

50

30

T/F The ductus of the premature infant is less responsive to oxygen

T