Background: Many centers advocate aggressive lower extremity deep venous thrombosis (DVT) screening using ultrasound (LUS) for patients meeting high-risk criteria. We hypothesized that a high-risk screening protocol is impractical and costly to implement.
Methods: The University of Virginia's trauma database was queried to identify 6,656 patients admitted between 2009 and 2013. Patient characteristics and outcomes were recorded. Multivariate analyses were performed on patients who underwent LUS to assess the association between patient characteristics and the development of DVT. A predictive model for DVT was applied to the entire population to determine performance and resources required for implementation.
Results: Overall, 2,350 (35.3%) of admitted patients underwent LUS. A total of 146 patients (6.2%) developed DVT. Patients who underwent LUS were significantly older (54.5 years vs. 50.4 years, p < 0.0001), had higher Injury Severity Scores (ISSs) (13.5 vs. 8.6, p < 0.0001), and had longer admissions to the intensive care unit (5.6 days vs. 0.9 days, p < 0.0001). Backward selection multivariable logistic regression identified intensive care unit length of stay, transfusion of blood products, spinal cord injury, and pelvic fracture to be associated with DVT (c statistic, 0.76). The model was applied to the entire population to evaluate probability of DVT (c statistic, 0.87). Predictive performance and costs were determined using a cost per LUS of $228. The most sensitive threshold for screening would detect 53% of DVTs, require screening of 26% of all trauma patients, and cost nearly $600,000 to implement during the study period.
Conclusion: Although a predictive model identified high-risk criteria for the development of DVT at our institution, the model demonstrated poor sensitivity and positive predictive value. These results suggest that implementing a high-risk screening protocol in trauma patients would require a costly and burdensome commitment of resources and that high-risk DVT screening protocols may not be practical or cost-effective for trauma patients.
Level of evidence: Therapeutic/care management study, level IV.