The value of lower-extremity duplex surveillance to detect deep vein thrombosis in trauma patients.

ABSTRACT

BACKGROUND: Venous duplex surveillance (VDS) is commonly used in trauma patients considered at risk for deep venous thrombosis. Economic evaluations have not addressed the quality of either the process of care or the outcomes achieved through the use of VDS. We sought to determine the value (quality/cost) of VDS in trauma patients stratified by risk for venous thromboembolism. METHODS: We reviewed records of all trauma patients from July 2006 to December 2010 who received weekly VDS examinations of the lower extremities. Prophylaxis and risk stratification were performed according to the American College of Chest Physicians recommendations. Patients were stratified by level of venous thromboembolism risk according to the results of a systematic review of the literature. The "value" of VDS was expressed as the number of clinically relevant findings divided by the cost (defined as the percent full-time equivalent of a certified vascular technologist performing VDS). RESULTS: A total of 2,169 patients met inclusion criteria and were stratified by deep venous thrombosis risk (218 moderate, 1,173 high, 778 highest). The quality of the process (the percent of sites adequately visualized per VDS) was not clinically different among risk groups. The quality of the outcome (number of clinically relevant findings) was significantly greater, and the work time required per finding was significantly lower in the highest-risk group (p < 0.001). The value of VDS was significantly greater in the highest-risk group compared with high or moderate-risk groups (1,104 vs. 337 vs. 76 findings per percent full-time equivalent, respectively; p < 0.001). CONCLUSION: VDS has significantly greater value in the highest-risk group and is warranted in this group. It is of less value in the moderate risk trauma patient. Calculating the value of specific health care interventions can guide the allocation of limited resources. LEVEL OF EVIDENCE Prognostic study, level II; value-based evaluation, level III.