In a surgical procedure, an anastomosis is created connecting one of the two subclavian arteries, responsible for supplying oxygenated blood to the neck and arms, with one of the pulmonary arteries, which transport blood from the right side of the heart to the lungs for oxygenation. This shunt serves as a temporary intervention for congenital heart conditions like tetralogy of Fallot, wherein blood low in oxygen is redirected back to the heart before reaching the lungs. By diverting the oxygen-depleted blood to the lungs, the shunt improves oxygen levels in the blood, enabling the child to survive and thrive until corrective surgery becomes feasible.