Pulmonary embolism.

Patients who are bedridden because of debilitating illness and patients who are recovering from major surgery are at particularly high risk of deep venous thrombosis and subsequent pulmonary embolism. "Mini-dose" heparin therapy has proved useful in preventing deep venous thrombosis. Because the clinical signs of pulmonary embolism are nonspecific, the patient's condition may deteriorate before the diagnosis is suspected. Ventilation and perfusion scans or pulmonary angiography confirm the diagnosis. Heparin continues to be the mainstay of therapy for pulmonary embolism.