Pulmonary embolism

It is reasonable to conclude by considering an approach to the diagnosis and treatment of pulmonary embolism. When the diagnosis is suspect, and in the absence of contraindications, or hemodynamic instability, treatment with heparin may be begun and an arterial blood gas and perfusion lung scan obtained. If the Pao2 and perfusion scan are normal, it is unlikely that significant pulmonary embolism has occurred. The presence of a perfusion scan defect and hypoxemia should suggest that a ventilation scan and/or evaluation for deep vein thrombosis is performed. A ventilation scan which shows absence of ventilation in areas where there is a perfusion defect, or failure to demonstrate deep vein disease, strongly mitigate against the diagnosis of pulmonary embolism. If the diagnosis is in doubt, pulmonary angiography should be performed. If the patient presents in shock, an angiogram should be performed, while heparin is administered and supportive measures are begun. If anticoagulants are contraindicated, or if re-embolization occurs after adequate anticoagulant therapy, consideration should be given to placement of a transcaval umbrella filter.