Subperiosteal Orbital Hematoma From SVC Occlusion During Cardiac Surgery: To See or Not to See.

We present a case in which the superior vena cava (SVC) cannula was inadvertently clamped for a short while during cardiopulmonary bypass, completely occluding SVC drainage. This resulted in a rarely seen complication - bilateral subperiosteal orbital hematomas causing orbital compartment syndrome. Other instances of intentional SVC occlusion include during the creation of a bidirectional cavo-pulmonary shunt and for emergency control of bleeding during thoracic surgery.