Z. C. Dietch1, B. Edwards1, M. Thames2, P. Shah1, M. Williams1, R. Sawyer1 1University Of Virginia,Department Of Surgery,Charlottesville, VA, USA 2University Of Virginia,School Of Medicine,Charlottesville, VA, USA
Introduction: Institutions may perform lower extremity ultrasound (LUS) screening for deep venous thrombosis (DVT) in trauma patients because therapeutic intervention is thought to reduce the incidence of pulmonary embolism (PE) in patients with DVT. However, disparate screening practices reflect a lack of consensus regarding clinical indications for screening and whether screening improves clinical outcomes. We hypothesized that LUS screening for DVT is not associated with reduced incidence of PE.
Methods: The 2012 American College of Surgeons National Trauma Data Bank Research Data Set was queried to identify 442,108 patients who were treated at institutions that reported performing at least one LUS and at least one DVT. Institutions that performed LUS on more than 2% of the admitted population were designated as screening (SC) facilities and remaining institutions were designated as non-screening (NSC) facilities. Patient characteristics and risk factors were used to develop a logistic regression model to assess the independent associations between LUS and DVT, and between LUS and PE.
Results: Overall, DVT and PE were reported in 0.94% and 0.37% of the study population, respectively. DVT and PE were more commonly reported in SC than NSC (DVT: 1.12% vs. 0.72%, p<0.0001; PE: 0.40% vs. 0.33%, p=0.0004). Patients treated at SC facilities were more severely injured (ISS>9) (39.1% vs. 34.9%, p<0.001) and significantly more likely to have at least one of 11 injuries or treatment variables commonly associated with DVT. Multivariable logistic regression demonstrated that LUS was independently associated with DVT (OR=1.44, CI 1.34-1.53) but not PE (OR=1.01, CI 0.92-1.12) (c-statistic 0.86 and 0.85, respectively). Sensitivity analyses performed at various rates for designating SC facilities, or limiting analyses to patients with length of hospital stay ≥3 days, did not alter the significance of these relationships (Table).
Conclusion: The performance of LUS in trauma patients is more likely to identify DVT but is not associated with a change in the incidence of pulmonary embolism. These findings suggest that LUS DVT screening protocols will detect many clinically insignificant DVTs for which subsequent therapeutic intervention may be unnecessary, and the use of these protocols should be questioned. Furthermore, in the absence of evidence that LUS decreases the rate of PE in trauma patients, consideration of DVT as a quality and performance measure should be abandoned until prospective, randomized trials further define the role for high-risk screening protocols.
