5. Transposition of the great vessels (TGA) Flashcards
Explain?
The aorta arises from the right ventricle and
the pulmonary artery from the left ventricle. In such cases there is usually a patent ductus arteriosus
(PDA) or a ventricular septal defect (VSD). Otherwise this case (Transposition of the great arteries) is
incompatible with life.
This condition depends on?
The whole condition depends upon the ventricular function and the state of
pulmonary (lung) field. It also depends on whether there is enough oxygen in the blood of the
coronary arteries
TGA separates?
TGA separates the pulmonary and systemic circulations by placing the two circuits in parallel rather
than in series. This arrangement forces desaturated blood from the systemic venous system to pass
through the RV and then return to the systemic circulation through the aorta without undergoing
normal oxygenation in the lungs. Similarly, oxygenated pulmonary venous return passes through the
LV and then back through the pulmonary artery to the lungs without imparting oxygen to the
systemic circulation
All separation and everything results in?
The result is an extremely hypoxic,
cyanotic neonate. Without intervention to create
mixing between the two circulations, TGA is a lethal
condition.
TGA is compatible with?
TGA is compatible with life in utero because
flow through the ductus arteriosus and foramen ovale
allows communication between the two circulations.
Oxygenated fetal blood flows ?
Oxygenated fetal blood flows from the placenta
through the umbilical vein to the right atrium, and then
most of it travels into the left atrium through the
foramen ovale. The oxygenated blood in the left atrium
passes into the LV and is pumped out the pulmonary
artery. Most of the pulmonary artery flow travels
through the ductus arteriosus into the aorta, instead of
the high-resistance pulmonary vessels, such that
oxygen is provided to the developing tissues.
