Superior vena cava syndrome

Cyanosis 15%

Markman, M. Cleveland Clinic Journal of Medicine, 1999

A/P #1

A/P #2

• Formed by merger of left/right brachiocephalic veins + azygous

• Venous blood from head/neck/upper extremities

• 6 to 8 cm in length

• 1.5 to 2 cm wide

• Abner, A. Chest, 1993

A/P #3

• SVC surrounded by rigid structures (ie mediastinum, sternum, right mainstem bronchus and LN)

• Thin walled and easily compressible secondary to low pressure

• Prone to obstruction relative to its “neighbors”

A/P #4

• As obstruction develops, venous collaterals form

• Alternate pathways for venous return to the RA

• Severity of sx depends on the time course of obstruction