Pulmonary embolism update. Lessons for the '90s.

Pulmonary embolism continues to be an underdiagnosed, potentially fatal problem. Because clinical diagnosis of pulmonary embolism is notoriously inaccurate, clinical suspicions must always be confirmed with objective studies. Evaluation generally begins with ventilation-perfusion lung scanning. Further evaluation is usually unnecessary if the lung scan is interpreted as normal (diagnosis excluded) or high-probability (diagnosis accepted). However, if the lung scan is indeterminate (referring to all other interpretations), additional diagnostic studies are usually required. Newer trends in the management of pulmonary embolism and deep venous thrombosis include a more aggressive initial regimen of heparin; simultaneous administration of warfarin with heparin, resulting in a shorter duration of heparin therapy; use of the international normalized ratio to monitor warfarin therapy; and use of a less intense warfarin regimen. Adjusted-dose subcutaneous heparin therapy and low-intensity warfarin therapy are newer prophylactic techniques for patients at moderate to high risk for deep venous thrombosis.