Lung Ultrasound on Admission to a Covid Decision Unit - Helpful in Differential Diagnosis or a Waste of Time?

Background In patients with Covid- 19, typical and often severe lung lesions have been reported. In addition to the use of chest CT, the diagnostic benefit of lung ultrasound has been advocated. This trial investigates if in patients presenting with symptoms compatible with Covid-19, lung ultrasound is of use in the early differential diagnosis. Methods This study includes 46 patients of the first wave of the Covid-19 pandemic (23 with confirmed infection, 23 controls with later on excluded infection), who were initially admitted to the Covid Decision Unit of an academic teaching hospital under the clinical suspicion of SARS-CoV-2 infection. All patients were examined by pulmonary ultrasound shortly after admission. The final diagnosis of infection was made or ruled out by means of - sometimes repeated - PCR of nasal/pharyngeal swabs. Findings of SARS-CoV-2 patients and controls were compared and analyzed for significant differences in chest sonographic parameters. Results There were significant differences in the lung ultrasound findings of both groups. In the Covid group there were significantly fewer A-lines, more pathological B-lines (increased or confluent) and more consolidations. Pleural effusions were significantly more frequent in the control group. The calculated lung ultrasound score (LUS) was higher in the Covid group than in the control group. However, a reliable differentiation between the two groups was not possible due to the wide range and overlap. Conclusion In a clinical setting, lung ultrasound reveals more frequent and different lesions in SARS-CoV-2 infected patients than in patients in whom the initial clinical suspicion was not confirmed. However, due to the overlap of findings between the two groups, lung ultrasound was not suitable to differentiate with sufficient certainty between SARS-CoV-2 infected and non-infected patients.