Fetal Transition WK1

Question 1

Fetal Circulation: Fetal PaO2

Answer 1

• UA 15-25mmHg
• UV 32-35mmHg

VS adult >60mmHg

Question 2

Fetal Circulation: site of gas exchange

Answer 2

• Intervillous space

Question 3

Fetal Circulation: Shunts

Answer 3

• Ductus venosus
• Ductus arteriosus
• Foramen ovale

Question 4

Fetal Circulation: High PVR RT

Answer 4

• Thick medial smooth muscle
• Vasoconstrictive prostaglandins
• Decrease O2 tension → vasoconstriction thick medial smooth muscle

Question 5

Fetal Transition: Lung Aeration RT (3)

Answer 5

• Labor
  
  • Na reabsorption
  • Fetal postural changes
• Postnatal
  
  • Pressure gradients generated by inspiration

Question 6

Fetal Transition: Lung aeration benefits

Answer 6

• Clearing fluid
• Allow air entry
• Decrease PVR
• Increase pulmonary blood flow

Question 7

Fetal Transition: Increase pulmonary blood flow -→

Answer 7

• Onset pulmonary gas exchange
• Pulmonary venous return provide preload LV

Question 8

Respiratory Transition: Phases

Answer 8

• Phase I - airways liquid filled 30-60s
• Phase II - airways cleared of liquid 4-6hr

Question 9

Respiratory Transition: Phase I

Answer 9

• Phase I - airways liquid filled 30-60s
  
  • High PVR
  • No pulmonary gas exchange

Question 10

Respiratory Transition: Phase II

Answer 10

• Phase II - airways cleared of liquid 4-6hr
  
  • Pulmonary gas exchange
  • Liquid in lung tissue → pulmonary edema
    
    • Stimulate increase pulmonary blood flow
    • Pos decreased respiratory function

Question 11

Fetal Transition: CV Postnatal

Answer 11

• Large decrease PVR
• Increase pulmonary blood flow

Question 12

Cord Clamping: Immediate Patho

Answer 12

• Loss umbilical venous return → loss preload → sudden decrease CO
• Loss low resistance placental circuit → increase SVR → rapid increase arterial pressure 30% in 4 heart beats → large increase afterload → decrease CO

Question 13

Delayed Cord Clamping

Answer 13

• Allow placental transfusion
• Increase bw
• Time based approach
• Decrease IVH

Question 14

Physiological Based Cord Clamping PBCC

Answer 14

• Lungs aerate and pulmonary blood flow increase before clamping
• NO loss preload, CO
• Decrease IVH

Question 15

Umbilical Cord Milking

Answer 15

• To replicate placental transfusion w delayed cord clamping
• Complications - large fluctuations BP (esp PT), IVH