Stage 2 Single Ventricle Palliation - Bidirectional Glenn Shunt
The ultimate aim of the staged single ventricle palliation is to ensure that all the oxygen-poor blue blood reaches the lungs without the help of a pumping chamber. Oxygen poor blue blood is carried from the body back to the heart via two large blood tubes called the superior vena cava SVC and the inferior vena cava IVC. In stage 2, half of the oxygen-poor blood is diverted to the lungs such that it flows without the help of a pumping chamber. For this, the superior vena cava carrying blood from the upper part of the body is connected to the pulmonary artery on the right side of the chest. Blood flows to either lung from this connection. This helps alleviate blue color to a great extent. The oxygen saturation levels are expected to be around 80-85 % after this procedure. Bidirectional Glenn is usually performed around 4-6 months of age. This surgery cannot be performed at birth. This is because, at birth, the lung pressure is naturally high and stays so for a few weeks. As discussed previously, low lung pressure is an absolute necessity for performing palliative surgeries in the single ventricle pathway. Hence, we must wait till the lung pressures are low enough to perform this surgery safely. The Glenn Shunt procedure may also be done for conditions such as hypoplastic left heart syndrome (HLHS), tricuspid atresia, and double outlet right ventricle.