Where There's Smoke, There's Fire: A Case Report of Turbulent Blood Flow in Lower Extremity Point-of-care Ultrasound in COVID-19.

Coronavirus disease 2019 (COVID-19) may predispose patients to increased risk of venous thromboembolism (VTE) due to various pathophysiological mechanisms, including but not limited to endothelial injury, inflammation, cytokine-mediated microvascular damage, and reactive thrombocytosis. A high risk of vessel thrombosis correlates with disease severity, making early identification and treatment of prime consideration.Although identification of a deep venous thrombosis (DVT) or pulmonary embolism warrants immediate treatment with anticoagulation, trying to predict which COVID-19 patients may be at increased risk for developing these pathologies is challenging. We present two cases of patients with COVID-19 who had ultrasonographic findings of turbulent blood flow within the deep venous system, without clear evidence of acute proximal DVT, who were subsequently found to have significant VTE. Point-of-care lower extremity ultrasound has become one of the core applications used by emergency physicians. Typically we perform compression ultrasound for DVT evaluation. This novel finding of turbulent blood flow, or "smoke," within the deep venous system, may serve as a marker of increased risk of clot development and could be an indication to consider early anticoagulation.