Bulging sclerae during cardiopulmonary bypass with venous congestion most likely indicates improper positioning of which cannula?

Bulging sclerae during cardiopulmonary bypass with venous congestion most likely indicates improper positioning of which cannula?

• A. Arterial return cannula
• B. Venous return cannula
• C. Left ventricular vent cannula
• D. Pulmonary artery catheter

Answer: (B)

During cardiopulmonary bypass, keeping good venous drainage is essential. When venous return is inadequate, venous pressure rises and blood pools in the systemic veins, especially in the head and neck. This venous congestion can cause features like facial edema and bulging sclerae. The sign points to improper positioning of the venous return cannula, because if the cannula tip is malpositioned, kinked, or obstructed, it cannot drain effectively from the right atrium via the superior and inferior vena cavae, leading to increased venous pressure and the observed bulging eyes. Arterial return cannula problems affect systemic perfusion, not venous congestion. A left ventricular vent cannula helps decompress the left heart and doesn’t typically cause venous eye signs. A pulmonary artery catheter is a monitoring device and its position doesn’t directly produce this venous congestion picture.

During cardiopulmonary bypass, keeping good venous drainage is essential. When venous return is inadequate, venous pressure rises and blood pools in the systemic veins, especially in the head and neck. This venous congestion can cause features like facial edema and bulging sclerae. The sign points to improper positioning of the venous return cannula, because if the cannula tip is malpositioned, kinked, or obstructed, it cannot drain effectively from the right atrium via the superior and inferior vena cavae, leading to increased venous pressure and the observed bulging eyes.

Arterial return cannula problems affect systemic perfusion, not venous congestion. A left ventricular vent cannula helps decompress the left heart and doesn’t typically cause venous eye signs. A pulmonary artery catheter is a monitoring device and its position doesn’t directly produce this venous congestion picture.