Prevalence and Predictors of Deep Vein Thrombosis in Critically Ill Medical Patients Who Underwent Diagnostic Duplex Ultrasonography

Introduction: Deep vein thrombosis (DVT) is a recognized but preventable cause of morbidity and mortality in the medical intensive care unit (MICU). We examined the prevalence and risk factors for DVT in MICU patients who underwent diagnostic venous duplex ultrasonography (DUS) and the potential effect on clinical outcomes. Methods: This is a retrospective study examining prevalence of DVT in 678 consecutive patients admitted to a tertiary care level academic MICU from July 2014 to 2015. Patients who underwent diagnostic DUS were included. Potential conditions of interest were mechanical ventilation, hemodialysis, sepsis, Sequential Organ Failure Assessment (SOFA) scores, central venous catheters, prior DVT, and malignancy. Primary outcomes were pulmonary embolism, ICU length of stay, and mortality. Additionally, means of thromboprophylaxis was compared between the groups. Multivariable logistic regression analysis was utilized to determine predictors of DVT occurrence. Results: Of the 678 patients, 243 (36%) patients underwent DUS to evaluate for DVT. The prevalence of DVT was 16% (38) among tested patients, and a prior history of DVT was associated with DVT prevalence (P <.01). Between cases and controls, there were no significant differences in central venous catheters, mechanical ventilation, hemodialysis, sepsis, SOFA scores, malignancy, and recent surgery. Patients receiving chemical prophylaxis had fewer DVTs compared to persons with no prophylaxis (14% vs 29%; P =.01) and persons with dual chemical and mechanical prophylaxis (P = 0.1). Fourteen percent of patients tested had documented DVT while on chemoprophylaxis. There were no significant differences in ICU length of stay (P =.35) or mortality (P =.34). Conclusions: Despite the appropriate use of universal thromboprophylaxis, critically ill nonsurgical patients still demonstrated high rates of DVT. A history of DVT was the sole predictor for development of proximal DVT on DUS testing. Dual chemical and mechanical prophylaxis does not appear to be superior to single-chemical prophylaxis in DVT prevention in this population.