Background: In patients with COVID-19, lung ultrasound can assess possible lung involvement. The examination is quick, performed at bedside and has a low risk of virus transmission. The aim of this study was evalute if lung ultrasound can predict the need for mechanical ventilation, admission to an intensive care unit, high-flow oxygen treatment, death of COVID-19.

Methods: A multicenter prospective cohort trial was performed during the first wave of the COVID-19 pandemic in Denmark. Film clips from focused lung ultrasound examinations were recorded and rated by blinded observers using different scoring systems.

Results: A total of 3,889 film clips of 398 patients were analyzed. Patients who died of COVID-19 after receiving intensive care treatment, mechanical ventilation or high-flow oxygen supplement had a significantly higher ultrasound score than those who survived or did not need these treatments. Multivariable logistic regression analyses showed that lung ultrasound predicts mechanical ventilation (RR 2.44, 95% CI 1.32 – 5.52), admission to intensive care (RR 2.55, 95% CI 1.41 – 54.59) and high-flow oxygen treatment (RR 1.95, 95% CI 1.5 – 2.53) when adjusting for sex, age and relevant comorbidity. There was no diagnostic difference between a scoring system using only anterolateral thorax zones and a scoring system that also included dorsal zones.

Interpretation: Focused lung ultrasound in patients with clinical suspicion of COVID-19 predicts respiratory failure requiring mechanical ventilation, admission to intensive care units and high-flow oxygen. Thus, focused lung ultrasound may be used to risk stratify patients with COVID-19 symptom