What is Bidirectional Glenn (BDG) without Cardio Pulmonary Bypass
Surgical approach is through median sternotomy. If there is only a single superior vena cava some surgeons prefer to decompress the upper body venous system by a shunt from innominate vein to right atrial appendage. Patient is fully heparinised (3mg/Kg) and cannulae are placed in the SVC innominate junction and the right atrial appendage and connected after de-ailing. This shunt is done
to avoid excess pressure developing in the cranial venous system when the superior vena cava is clamped. However in most cases one can do the operation without a shunt.
The superior vena cava is mobilised completely and taped. Right pulmonary artery is also dissected from its origin to the point it gives rise to branches at right haulm. The SVC is clamped in two places, divided and the end close to right atrium is over sewn. A partial occlusion clamp is applied 011 the light pulmonary artery and incision is made on its superior aspect. The end of superior vena cava is anastomosed to the superior aspect of right pulmonary artery. The clamps are removed. Superior vena caval blood flows into both pulmonary arteries. It is a good idea to ligate azygos vein if it has not been already done.
If there is bilateral superior vena cava, bi-directional Glenn operation is done on both sides. Any pre-existing systemic pulmonary artery shunt is ligated after bi-directional Glenn operation.