Why is Prostaglandin E1 prescribed for a child with transposition of the great arteries?

Prostaglandin E1 is used in the management of transposition of the great arteries because it helps to maintain adequate blood flow and oxygenation in the body. In this condition, the aorta and pulmonary artery are switched, which can lead to inadequate oxygen saturation and impaired cardiac output since oxygen-poor blood is sent to the body, and oxygen-rich blood is sent back to the lungs.

Administering Prostaglandin E1 causes vasodilation of the ductus arteriosus, a fetal blood vessel that connects the aorta and pulmonary artery. By keeping this ductus open, it allows for mixing of the oxygenated and deoxygenated blood, which helps improve overall oxygen saturation levels and supports better cardiac output. This is critical in a child with transposition of the great arteries until surgical intervention can correct the anatomical defect.

Ensuring that there is adequate mixing of blood not only optimizes oxygen delivery to the tissues but also helps in stabilizing the child's hemodynamic status. Thus, the correct rationale for prescribing Prostaglandin E1 in this case is to provide adequate oxygen saturation and maintain cardiac output.