SCMC Fetal Circulation Superior Parallel circulation Ductus arteriosus (combined output) Ductus venosus shunts blood from the uv to the Foramen IC bypassing the liver ovale Foramen Ovale shunts blood from the ra to the la Ductus venosus Ductus arteriosus shunts blood from the pa to the descending aorta bypassing the lungs Blood from the lv perfuses the heart brain with well oxygenated blood
Fetal Circulation – Parallel circulation (combined output) – Ductus Venosus shunts blood from the UV to the IVC bypassing the liver – Foramen Ovale shunts blood from the RA to the LA – Ductus Arteriosus shunts blood from the PA to the descending aorta bypassing the lungs – Blood from the LV perfuses the heart & brain with well oxygenated blood 50% 2/3
SCMC Fetal Circulation A胎儿期 B出生后 Ductus arteriosus 由母体循环完成气体由肺循环完成气体 交换 交换 多为混合血,心脑静脉血和动脉血分mn 上半身血氧含量高于开 下半身 50% Ductus venosus 卵圆孔、动脉导管、卵圆孔、动脉导管、 静脉导管开放 静脉导管闭合 肺动脉压与主动脉相肺动脉压下降,肺umwi 似,肺循环阻力高「循环阻力低 右心室高负荷 左心室高负荷
Fetal Circulation 50% 2/3 A胎儿期 B出生后 由母体循环完成气体 交换 由肺循环完成气体 交换 多为混合血，心、脑、 上半身血氧含量高于 下半身 静脉血和动脉血分 开 卵圆孔、动脉导管、 静脉导管开放 卵圆孔、动脉导管、 静脉导管闭合 肺动脉压与主动脉相 似，肺循环阻力高 肺动脉压下降，肺 循环阻力低 右心室高负荷 左心室高负荷
SCMC Transitional Circulation Dramatic changes in circulation at the moment of birth and onwards Air breadth-lung expansion-Rp i Qp↑- LA pressure↑-PFO↓ POT- ductus arteriosus and venosus Obliteration of placental circulation Rs↑ Persistance of the Fetal Circulatin IVC pressure↓-PFO
Transitional Circulation Dramatic changes in circulation at the moment of birth and onwards : – Air breadth - lung expansion - Rp ↓ – Qp ↑ - LA pressure ↑ - PFO ↓ – P O2 ↑ - ductus arteriosus and venosus ↓ – Obliteration of placental circulation - Rs ↑ – IVC pressure ↓ - PFO ↓
SCMC Foramen Ovale e Closure occurs in two stages Functional closure occurs when LA pressure higher than RA pressure e This is reversible in the presence of hypoxemia or hypovolemia Permanent closure occurs in 5-7 months
Foramen Ovale ⚫ Closure occurs in two stages – Functional closure occurs when LA pressure higher than RA pressure ⚫ This is reversible in the presence of hypoxemia or hypovolemia – Permanent closure occurs in 5-7 months
SCMC Foramen Ovale Probe Patency s present in 50% of children 5 years old in more than 25% of adults Is a potential avenue for air emboli to enter the systemic circulation A patent Fo may be beneficial in certain heart malformations Patients who rely on the patency of the foramen require a balloon atrial septoplasty
Foramen Ovale ⚫ Probe Patency – Is present in 50% of children < 5 years old & in more than 25% of adults – Is a potential avenue for air emboli to enter the systemic circulation – A patent FO may be beneficial in certain heart malformations – Patients who rely on the patency of the foramen require a balloon atrial septoplasty