Lung ultrasound as a screening tool for SARS-CoV-2 infection in surgical patients

Purpose To evaluate the diagnostic performance of lung ultrasound (LUS) in screening for SARS-CoV-2 infection in patients requiring surgery. Methods Patients underwent a LUS protocol that included a scoring system for screening COVID-19 pneumonia as well as RT-PCR test for SARS-CoV-2. The receiver operator characteristic (ROC) curve was determined for the relationship between LUS score and PCR test results for COVID-19. The optimal threshold for the best discrimination between non-COVID-19 patients and COVID-19 patients was calculated. Results Among 203 patients enrolled (mean age 48 years; 82 males), 8.3% were COVID-19-positive; 4.9% were diagnosed via the initial RT-PCR test. Of the patients diagnosed with SARS-CoV-2, 64.7% required in-hospital management and 17.6% died. The most common ultrasound findings were B lines (19.7%) and a thickened pleura (19.2%). The AUC of the ROC curve of the relationship of LUS score with a cutoff value >8 versus RT-PCR test for the assessment of SARS-CoV-2 pneumonia was 0.75 (95% CI 0.61-0.89; sensitivity 52.9%; specificity 91%; LR (+) 6.15, LR (-) 0.51). Conclusion The LUS score in surgical patients is not a useful tool for screening patients with potential COVID-19 infection. LUS score shows a high specificity with a cut-off value of 8.