Abstract
OBJECTIVE: There are no societal ultrasound (US) guidelines detailing appropriate patient selection for deep vein thrombosis (DVT) imaging in patients with COVID-19, nor are there protocol recommendations aimed at decreasing exposure time for US technologists. We aimed to provide COVID-19-specific protocol optimization recommendations limiting US technologist exposure while optimizing patient selection. METHODS: A novel two-pronged algorithm was implemented to limit the DVT US studies on patients with COVID-19 prospectively, which included direct physician communication with the care team and a COVID-19-specific imaging protocol was instated to reduce US technologist exposure. To assess the pretest risk of DVT, the sensitivity and specificity of serum d-dimer in 500-unit increments from 500 to 8000 ng/mL and a receiver operating characteristic curve to assess performance of serum d-dimer in predicting DVT was generated. Rates of DVT, pulmonary embolism, and scan times were compared using t-test and Fisher's exact test (before and after implementation of the protocol). RESULTS: Direct physician communication resulted in cancellation or deferral of 72% of requested examinations in COVID-19-positive patients. A serum d-dimer of >4000 ng/mL yielded a sensitivity of 80% and a specificity of 70% (95% confidence interval, 0.54-0.86) for venous thromboembolism. Using the COVID-19-specific protocol, there was a significant (50%) decrease in the scan time (P < .0001) in comparison with the conventional protocol. CONCLUSIONS: A direct physician communication policy between imaging physician and referring physician resulted in deferral or cancellation of a majority of requested DVT US examinations. An abbreviated COVID-19-specific imaging protocol significantly decreased exposure time to the US technologist.