SCMC Ductus Arteriosus e Closure occurs in two stages 80%Functional closure occurs 24 hours after birth This is reversible in the presence of hypoxemia or hypovolemia 80% Permanent closure occurs in 3 months 95% Permanent closure occurs in 3 months e Fibrous connective tissue forms permanently seals the lumen This becomes the ligamentum arteriosum
Ductus Arteriosus ⚫ Closure occurs in two stages – 80% Functional closure occurs 24 hours after birth ⚫ This is reversible in the presence of hypoxemia or hypovolemia – 80% Permanent closure occurs in 3 months – 95% Permanent closure occurs in 3 months ⚫ Fibrous connective tissue forms & permanently seals the lumen – This becomes the ligamentum arteriosum
SCMC Persistent ductus Arteriosus The Pda in the preterm infant is due to a weak vasoconstrictor response to O2 and should be considered a normal not pathologic response This pda may still need surgical correction o a left to right shunt through the ductus can flood the lungs of the premature infant prolonging mechanical ventilation, eventually leading to pulmonary edema right sided heart failure
Persistent Ductus Arteriosus The PDA in the preterm infant is due to a weak vasoconstrictor response to O2 and should be considered a normal not pathologic response ⚫ This PDA may still need surgical correction ⚫ A left to right shunt through the ductus can flood the lungs of the premature infant prolonging mechanical ventilation, eventually leading to pulmonary edema & right sided heart failure
SCMC Persistent ductus Arteriosus o A PDA may also be beneficial In cyanotic congenital heart malformations with right to left decreased pulmonary blood flow The PDa may be the major route by which the blood reaches the pulmonary arteries to receive O2 e In this case closure of the da causes severe cyanosis tissue ypoxia acidemia To keep the ductus open prior to palliative or corrective surgery of the heart malformation, PGE 1(0.05-0. mcg/kg/min) can be administeredⅣV To help close the ductus prior to surgical intervention to ligate the PDA, Indomethacin(0. 1-0.2mg/kg)can be administered This is an inhibitor of PGE synthesis
Persistent Ductus Arteriosus ⚫ A PDA may also be beneficial – In cyanotic congenital heart malformations with right to left & decreased pulmonary blood flow ⚫ The PDA may be the major route by which the blood reaches the pulmonary arteries to receive O2 ⚫ In this case closure of the DA causes severe cyanosis, tissue hypoxia & acidemia ⚫ To keep the ductus open prior to palliative or corrective surgery of the heart malformation, PGE 1 (0.05-0.1mcg/kg/min) can be administered IV ⚫ To help close the ductus prior to surgical intervention to ligate the PDA, Indomethacin (0.1-0.2mg/kg) can be administered – This is an inhibitor of PGE synthesis
SCMC Transitional Neonatal circulation FETAL CIRCULAT/ON (PARALLEL J RA. RAO RVD PA D LAL∨Ao TRANSIT/ONAL CIRCULAT/ON 1SER1 ES OR A4R4LLEL丿 事RARV事PA LAL∨Ao NORMAL CIRCULAT/ON SERIES) RA◆R√◆PA事 O AOQ LVO LA
Transitional & Neonatal Circulation
Cardiovascular differences in the CMC Infant o There are gross structural differences& changes in the heart during infancy At birth the right left ventricles are essentially the same in size wall thickness During the 1st month volume load afterload of the lv increases whereas there is minimal increase in volume load decrease in afterload on the rv e By four weeks the Lv weighs more than the rv This continues through infancy early childhood until the Lv is twice as heavy as the RV as it is in the adult
Cardiovascular Differences in the Infant ⚫ There are gross structural differences & changes in the heart during infancy – At birth the right & left ventricles are essentially the same in size & wall thickness – During the 1st month volume load & afterload of the LV increases whereas there is minimal increase in volume load & decrease in afterload on the RV ⚫ By four weeks the LV weighs more than the RV ⚫ This continues through infancy & early childhood until the LV is twice as heavy as the RV as it is in the adult