A link between inflammatory biomarkers and lung ultrasound observations in patients with SARS-CoV-2 infection

Lung ultrasound (LUS) has shown to correlate well with the findings obtained by chest computed tomography (CT) in acute-phase COVID-19. Although there is a significant correlation between blood biomarkers and CT radiological findings, a potential correlation between biochemical parameters and LUS images is still unknown. Our purpose was to evaluate a potential association between lung lesions visualised by LUS and blood biomarkers as well as the ability to predict mortality from two different lung ultrasound scoring systems (LUSS). We performed a retrospective observational study on 45 patients aged >70 years with SARS-CoV-2 infection who required hospitalisation. LUS was carried out at admission and on day 7, when the clinical course was favourable or earlier in case of worsening. Disease severity was scored by means of LUSS in 8 (LUSS8) and in 12 (LUSS12) quadrants. LUS and blood draw for inflammatory marker analysis were performed at the same time. The correlation between biochemical parameters and either LUSS score was significant for ferritin levels. It was 0.486 (p=0.001) for LUSS8 and 0.458 (p=0.002) for LUSS12. Using a threshold score of 15 with LUSS12 predicted mortality in 86.7% of cases (OR_crude 31, CI 95% 4.79–200.51). Applying a threshold of 10 with LUSS8 predicted mortality in 88.9% (OR_crude 69.75, CI 95% 6.90–705.20). There is a correlation between ferritin levels and LUSS. The prognostic capacity of LUSS12 does not surpass that of LUSS8.