Efficacy and safety of sonographer discretion to terminate a venous duplex ultrasound for diagnosis of deep vein thrombosis in coronavirus disease 2019 patients

Abstract

Objective: Sonographers performing venous duplex ultrasound (VDUS) of patients with coronavirus disease 2019 (COVID-19) have an increased risk of exposure owing to their close contact with these patients for an extended period. The objective of the present study was to evaluate the efficacy of a modified COVID-19 VDUS protocol to reduce sonographer exposure to COVID-19 patients.

Methods: We performed a single-center retrospective review. Patients who had undergone VDUS under the modified COVID-19 protocol between March 1, 2020, and June 30, 2020, with a confirmed or presumed COVID-19 diagnosis at the VDUS were included. The modified COVID-19 protocol was defined as the ability of the sonographer to terminate the examination on detection of an acute deep vein thrombosis (DVT). The primary outcome measures were the number of anatomic deep venous segments recorded by the sonographer, which was used as a surrogate measure for sonographer exposure time, and the number of acute DVTs found on follow-up examinations in segments not visualized at the index VDUS.

Results: A total of 160 lower extremity VDUS (LEVDUS) scans and 72 upper extremity VDUS (UEVDUS) scans were performed using the modified COVID-19 protocol. The index VDUS had found an acute DVT for 44 of 160 patients (27.5%) who had undergone LEVDUS and 26 of 72 (36.6%) who had undergone UEVDUS. On follow-up imaging, 7 of 38 LEVDUS scans (17.9%) and 1 of 10 UEVDUS scans (10%) had demonstrated a new acute DVT. Malignancy and surgery 30 days before imaging were significantly associated with acute lower extremity DVT, and mechanical ventilation and extracorporeal membrane oxygenation were associated with acute upper extremity DVT. On the index VDUS, the average was 10.6 of 12 total visualized segments on LEVDUS and 6.4 of 10 total segments on UEVDUS. Of the index VDUS scans, 35.6% of the LEVDUS and 78.6% of the UEVDUS scans had been abbreviated. The index VDUS scans that were positive for acute DVT had had significantly fewer visualized segments for both lower (8.4 vs 11.5; P < .0001) and upper (4.2 vs 7.6) extremities (P < .0001). On the follow-up examinations, only one of eight new acute DVTs had been found in a patient whose index VDUS had been abbreviated and the corresponding segment not assessed. These findings did not affect the patient's clinical course.

Conclusions: The modified COVID-19 VDUS protocol reduced sonographers' potential exposure time to COVID-19. Additionally, the clinical efficacy was maintained, with no missed DVTs, despite the abbreviation of the VDUS examinations.

Keywords: COVID-19; DVT; Duplex ultrasound; Technologist exposure.