Cardiovascular changes at birth Flashcards
A day after delivery, a premature infant is examined by a neonatal specialist. With her stethoscope, she hears a harsh blowing murmur throughout the cardiac cycle, more intense when the heart is ejecting blood (ventricular systole) and less intense when the ventricle is filling (ventricular diastole).
A patent ductus arteriosus
(contd.)
The murmur of a PDA is cause by turbulent blood flow from the aorta to the pulmonary artery. There is a always a pressure gradient between them, though somewhat greater in systole than in diastole, so the murmur is heard throughout the cardiac cycle and is described as a “machinery murmur”
what carries oxygenated blood from placenta to foetus
umbilical vein
what carries deoxygenated blood back to the placenta from the foetus
2 umbilical arteries
what does the ductus arteriosus connect to
aorta and pulmonary artery - keeps blood away from lungs filled with amniotic fluid
provides outlet flow so decreased resistance and increased flow
what does the ductus venous allow
blood from placenta to bypass the liver as docent work fully yet
function of foramen ovale
allows blood flow from right atrium into Left atrium
In utero why is the pressure higher in the right atrium than the left ?
due to vasoconstriction
where does blood flow from the IVC travel through
through foramen oval to left atrium then to left ventricle to the brain
what is pulmonary vasoconstriction
reduced blood flow to the lungs diverts pulmonary artery through ducterious arterosus , RA increased pressure keeping it open
what can occur if baby is born hypoxic
COPD
if the RA pressure is greater then LA what stays open
Foramen ovale
pressure = flow x ?
resistance
potential difference = current x
resistance
does vasoconstriction increase resistance
yes
how is adequate O2 delivery to tissues achieved by
fetal HB
fetal circulation
polycythaemia (increased RBC)
