What is a Bidirectional Glenn Procedure?
The bidirectional Glenn procedure is the surgery used to prepare the heart for a Fontan procedure. It is used in children with congenital heart defects in which only one of the main pumping chambers (the ventricles) can be used. The Glenn is used for many types of complex congenital heart disease, like tricuspid atresia. The procedure involves re-plumbing the heart so that the blood from the upper body flows directly into both lungs without going through a pumping heart chamber.
Preparing for the Procedure
Prior to surgery, the child will have tests to diagnose the heart defects, including an EKG, a chest x-ray and an echocardiogram. In addition, a cardiac catheterization is conducted to diagnose the congenital heart defect and to measure the pressure inside the lung blood vessels to assure that the pressure is low. Blood tests are conducted to be sure there is no infection, no problem with clotting and normal electrolytes. Prior to surgery, blood tests to determine blood type and compatibility are performed to prepare for the use of blood during surgery.
During the Procedure
During this procedure, the child is placed under general anesthesia, and special monitoring IVs are put in. The chest is entered through the sternum (breastbone). The heart/lung machine is then connected. Any procedure that needs to be done inside the heart is carried out while the heart is empty and stopped. The superior vena cava (the main blood vessel returning the dark, unoxygenated blood from the head and the upper body) is cut off from the heart and connected to the pulmonary artery. Any other existing connection like a shunt that is connected to the pulmonary artery is closed. The heart is allowed to resume its normal function. Temporary pacemaker wires and drains are placed and the chest is closed. The baby is allowed to awaken within a few hours and taken off the respirator. Oxygen blood levels do not reach normal levels after this surgery, since all the blood from the inferior vena cava (all the blood returning from the lower body is still mixing with the oxygenated blood within the heart. The procedure does allow the superior vena cava blood, about 40% of the blood, to flow passively through the lung. This change decreases the workload of the heart.
After the Procedure
After surgery the child will need a few days to recover from anesthesia, the use of the heart-lung bypass equipment, and the surgery. The child will initially be on a ventilator (breathing machine). Once the breathing tube is out, the main goals of care are pain control, taking care of the lungs by deep breathing, walking (if old enough) and eating.