Pulmonary artery catheter occlusion as an indication of pulmonary embolus.

Two patients with respiratory failure had consistently reproducible findings on insertion of flow directed pulmonary artery catheters which led to the subsequent diagnosis of pulmonary embolus. Occlusion of the catheter tip and development of a rising "overwedge" tracing on deflation of the balloon may mean the catheter tip has become embedded in clot. When combined with the inability to obtain a wedge tracing, the deflation "overwedge" tracing should alert the physician to the possibility of unsuspected pulmonary embolus.