Suspected superior vena cava syndrome: the role of the Swan-Ganz catheter.

The use of the Swan-Ganz flow-directed catheter in establishing the diagnosis of the superior vena cava syndrome in two patients (one with Hodgkin's disease and the other with carcinoma of the lung) is described. A pressure tracing showing elevated pressure above the obstruction without respiratory or cardiac fluctuations is characteristic of obstruction of the superior vena cava.