Use of the Greenfield filter in patients with major trauma.

Patients with major trauma often cannot be given the benefit of preventive measures such as pneumatic compression boots and low-dose heparin against pulmonary embolism. The Greenfield filter is accepted as a safe and effective method of prophylaxis of this complication. The aim of this study was to evaluate the efficacy of placement of the Greenfield filter in 161 patients with major trauma. Between January 1984 and July 1988, 94 patients with an injury severity score (ISS) of > 16 were treated. This score is predictive of a mortality rate of at least 10% and defines major trauma based on anatomic injury. Some 20% (19 of 94) of these patients developed deep vein thrombosis despite standard prophylactic measures and 8% (eight of 94) suffered pulmonary embolism, two of which were fatal. Pulmonary embolism occurred without antecedent evidence of deep vein thrombosis in another 15% of patients (14 of 94), three of which caused death. From August 1988 until July 1992, of 67 other patients with an ISS > 16, 13% (nine of 67) developed deep vein thrombosis and 1% (one of 67) had a pulmonary embolism; this was not statistically significant (P > 0.25). Of these 67 patients who were considered to be at high risk of pulmonary embolism, because of a contraindication to anticoagulation or physical impediment to sequential compression boots, 29 had prophylactic placement of a Greenfield filter. No pulmonary emboli occurred in these patients. During long-term follow-up (mean 32.8 (range 4-58) months), 84% of the surviving patients (21 of 25) underwent duplex ultrasonography of the inferior vena cava; patency of the vessel was confirmed in all patients.