The Effect of Percutaneous Superior Venae Cava Cannulation Clamping on Cerebral Near Infrared Spectroscopy in MICS

The use of minimally invasive cardiac surgery has progressed over the last 5-10 years to allow access to the heart through a small incision in the right chest. This avoids the use of a sternotomy incision through the bone in the front of the chest. The benefits of such an approach are cosmetic (smaller incision not easily visible) and faster recovery. The minimally invasive approach also eliminates the risk of sternal wound infection. Minimally invasive cardiac surgery however poses additional challenges; one of the biggest is access to the large blood vessels which need to be cannulated to allow the heart lung machine to function. In conventional surgery, these vessels are easily accessed as they are entering or leaving the heart. In minimally invasive surgery, the cannula are placed into easily accessible arteries and veins, traditionally the femoral vessels. These vessels are smaller than those by the heart and so require smaller cannula, which provide challenges to the heart lung machine. One way around this is to use more cannulae and so cannulation of a vein in the neck is also performed. This cannula however, has been associated with neck hematoma, tearing of the vein and blood loss. While placement of the cannula in the neck is routine at LHSC now, when this surgery was first performed here 10 years ago, it was done so without the neck cannula and with no injury to patients. The purpose of this study therefore, is to more rigorously study the effect of the neck cannula on heart lung bypass, and more specifically to see if oxygen delivery to the organs, and the brain in particular is sufficient to avoid hypoxia.