Prophylactic Greenfield filter placement in selected high-risk trauma patients

Pulmonary embolus (PE) remains a major factor in morbidity and death in severely injured patients, especially those in specific high-risk groups. PEs have been documented to occur despite routine deep venous thrombosis prophylaxis. The purpose of this study was to evaluate the safety and efficacy of prophylactic Greenfield filter (PGF) placement in patients who have multiple trauma with known high-risk injuries for PE.

From January 1992 to June 1994, PGF were prospectively placed in 108 patients who had an injury severity score greater than 9 and met one of the following criteria: (1) severe head injury with prolonged ventilator dependence, (2) severe head injury with multiple lower extremity fractures, (3) spinal cord injury with or without paralysis, (4) major abdominal or pelvic penetrating venous injury, (5) pelvic fracture with lower extremity fractures. These patients were compared with 216 patients, historically matched for age, sex, mechanism of injury, injury severity score, and days in the intensive care unit. Data analysis was done with chi-squared and Student's t testing.

There were no statistical differences between the PGF and control group with regard to age (35.9 +/- 1.5 vs 38.3 +/- 1.4), sex (male 76% vs 75.5%), days in the intensive care unit (21.2 +/- 1.4 vs 18.1 +/- 1.5), ISS (28.0 +/- 1.0 vs 25.4 +/- 0.8) and mechanism of injury (blunt 85% vs 81%). None of the patients in the PGF group had a PE. In the control group, however, 13 patients had a PE, nine of which were fatal. These differences were statistically significant for both PE (p < 0.009) and PE-related death (p < 0.03). The overall mortality rate was reduced in the PGF group (18 of 108, 16%) versus the control group (47 of 216, 22%); however, this did not achieve statistical significance.

PGF insertion in selected patients at high risk who had trauma effectively prevented both fatal and nonfatal PE. The lower incidence of fatal PE in the PGF group may have contributed to a reduction in the overall mortality rate. Patients who have trauma with high risk for PE should be considered for PGF placement.