What is the Glenn procedure?
The Glenn procedure (sometimes referred to as a bi-directional Glenn or Hemi-Fontan procedure) is an intermediate step in the series of single-ventricle heart surgeries. It marks the end of the "interstage" period, and is typically done at four to six months of age.
During this operation, doctors remove the shunt (the tube supplying pulmonary blood flow). After the shunt is gone, blood flows to the lungs in an uncommon way. It flows from the upper part of the body directly into the lungs. There is no pump pushing the flow, rather it flows passively through the lungs on its own.

Why does my child need a Glenn procedure?
The Glenn operation is an intermediate step between the Norwood and Fontan operations. It is an important part of the single ventricle surgical strategy because it helps to prepare the heart and lungs for the passive type of lung circulation that comes with the third surgery, the Fontan procedure.
During this surgery, the large vein that returns blood from the head and upper extremities is detached from the heart and is directed to the arteries leading to the lungs. With this shunt, blood without oxygen is delivered directly to the lungs and therefore is more efficient, allowing the heart to work easier after the Norwood procedure. This creates a more stable situation for your baby and the risk of problems is usually less than after the Norwood procedure.
How long does the Glenn procedure take?
This surgical procedure typically takes four to five hours and the recovery time is generally shorter than after the Norwood. Babies will also typically spend less time on the breathing machine and less time in the ICU than after the Norwood. They usually begin eating within a day or two of surgery and their hospital stay is commonly 10 to 14 days.
What should I expect after the Glenn procedure?
After the Glenn and Norwood operations are complete, the good news is that your child will not need to be monitored as closely. Their oxygen saturations will remain lower than normal after this surgery (usually between 75% to 85%). In many cases, doctors recommend that kids stay on oxygen full-time for approximately one month following surgery. This helps decrease the pressure in the lungs so the blood can flow through them more easily.