Bidirectional Glenn Procedure

Some children are born with only one working pumping chamber, as in hypoplastic left heart syndrome or tricuspid atresia. They are treated with a series of operations that, step by step, send the body's returning blue blood straight to the lungs so the single ventricle only has to pump to the body. The bidirectional Glenn is the second step. It joins the superior vena cava, the vein that drains the head and arms, to the right pulmonary artery, so that blood flows passively into both lungs. It is not done before about 2 months of age because the lung vessels are still too stiff, and it is usually done at 4 to 10 months, often after a Norwood operation or a shunt. The operation is usually done through a repeat median sternotomy with cardiopulmonary bypass, mild cooling and no cross-clamp. The old shunt is closed, the superior vena cava is divided and sewn to the top of the right pulmonary artery, and the heart end of the vein is sewn shut. Narrow pulmonary arteries can be widened with a patch at the same time. Some surgeons prefer the hemi-Fontan, a related operation that joins the pulmonary arteries to the top of the right atrium and makes the final Fontan step simpler. In selected children the Glenn is done without bypass, either with a temporary tube that drains head blood into the heart or with brief clamping alone. While the vein is clamped, blood can back up into the head, so pressures and brain oxygen are watched closely. After surgery, problems include fluid around the lungs (pleural effusion or chyle), clots in the new connection, and later abnormal vessels in the lungs. For the scrub, this is a pediatric open-heart setup that often starts with a redo sternotomy and depends on fine vascular clamps, clips and fine polypropylene.