Left-sided superior vena cava and venous hyperoxia masquerading as inadvertent carotid artery catheterization.

BACKGROUND: A persistent left-sided superior vena cava (PLSVC) is a rare, often asymptomatic, venous anomaly that may be first diagnosed during central venous catheterization. During chest radiograph interpretation, a PLSVC can be confused with inadvertent arterial catheterization.

CASE REPORT: We describe the presentation of a 45-year-old man with end-stage liver disease who required central venous catheterization for treatment of septic shock. An aberrantly placed catheter noted on chest radiograph and an elevated central venous oxygen saturation gave the appearance of inadvertent carotid artery catheterization. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: A persistent left-sided superior vena cava can masquerade as an inadvertent cannulation of the carotid artery during central line placement. It is important for emergency physicians to be aware of this possibility when evaluating a chest radiograph with an aberrantly placed catheter. Venous hyperoxia may further complicate attempts to differentiate between arterial and venous catheterization in patients with septic shock. After confirmatory tests, the emergency physician should consider removal of the catheter due to potential complications.