Accidental mediastinal entry via left internal jugular vein cannulation.

Two cases are reported in which mediastinal penetration by a pulmonary artery catheter and a temporary venous pacemaker wire occurred following cannulation of the left internal jugular vein and placement of an indwelling venous introducer sheath. The anatomy of the left internal jugular vein and possible mechanisms of accidental mediastinal penetration with this approach are discussed. Extreme caution must be exercised when using the left internal jugular venous access route and an indwelling venous introducer sheath.