Sunday, November 14, 2010

Transpostion of the Great Vessels (d-TGA)

    Aorta arises from RV and pulmonary artery from LV creating parallel circulations.

1 - atrial septal defect or patent foramen ovale
2 - aorta connected to right ventricle
3 - patent ductus arteriosus
4 - pulmonary artery connected to left ventricle
With the presence of an atrial septal defect, two parallel blood flows exist, with one recirculating oxygenated blood and one recirculating de-oxygenated blood. As shown in this diagram, mixing occurs via the atrial septal defect.

Cyanotic defect resulting in delivery of  inadequately oxygenated blood. 

Parallel circulation exists as systemic venous blood enters the right heart normally but exits through the aorta back to the body.

Pulmonary venous blood (oxygenated blood) enters the left heart normally but exits through the PA to the lungs

Requires intracardiac mixing to survive. Degree of cyanosis/acidosis depends on number, location and size of intracardiac and extracardiac shunts- ASD, VSD, PDA.

Depends on degree of shunting.

Cyanosis within 24 hours of birth most common and if septum is intact.

Hepatomegaly, tachycardia, tachypnea if with VSD.

IV, O2, Monitor

3cc/kg/hr D10W  for infants under 1 year of age, D5W if over 1 year.

Stabilization on prostaglandins necessary if atrial communication not sufficient.

If large VSD present may need CHF management, consider Lasix

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