Lung ultrasound in predicting COVID-19 clinical outcomes: A prospective observational study

Abstract

Study objective: We sought to determine the ability of lung point-of-care ultrasound (POCUS) to predict mechanical ventilation and in-hospital mortality in patients with coronavirus disease 2019 (COVID-19).

Methods: This was a prospective observational study of a convenience sample of patients with confirmed COVID-19 presenting to 2 tertiary hospital emergency departments (EDs) in Iran between March and April 2020. An emergency physician attending sonographer performed a 12-zone bilateral lung ultrasound in all patients. Research associates followed the patients on their clinical course. We determined the frequency of positive POCUS findings, the geographic distribution of lung involvement, and lung severity scores. We used multivariable logistic regression to associate lung POCUS findings with clinical outcomes.

Results: A total of 125 patients with COVID-like symptoms were included, including 109 with confirmed COVID-19. Among the included patients, 33 (30.3%) patients were intubated, and in-hospital mortality was reported in 19 (17.4%). Lung POCUS findings included pleural thickening 95.4%, B-lines 90.8%, subpleural consolidation 86.2%, consolidation 46.8%, effusions 19.3%, and atelectasis 18.3%. Multivariable logistic regression incorporating binary and scored POCUS findings were able to identify those at highest risk for need of mechanical ventilation (area under the curve 0.80) and in-hospital mortality (area under the curve 0.87). In the binary model ultrasound (US) findings in the anterior lung fields were significantly associated with a need for intubation and mechanical ventilation (odds ratio [OR] 3.67; 0.62-21.6). There was an inverse relationship between mortality and posterior lung field involvement (OR 0.05; 0.01-0.23; and scored OR of 0.57; 0.40-0.82). Anterior lung field involvement was not associated with mortality.

Conclusions: In patients with COVID-19, the anatomic distribution of findings on lung ultrasound is associated with outcomes. Lung POCUS-based models may help clinicians to identify those patients with COVID-19 at risk for clinical deterioration.Key Words: COVID-19; Lung Ultrasound; Mechanical ventilation; Prediction; ICU admission; Mortality; Clinical outcome; Risk stratification; Diagnostic accuracy.

Keywords: COVID‐19; ICU admission; clinical outcome; diagnostic accuracy; lung ultrasound; mechanical ventilation; mortality; prediction; risk stratification.

FIGURE 1

Heat map demonstrating the geographical distribution and types of lung POCUS findings among enrolled patients. In each hemithorax, lung zones include anterior superior (AS), anterior inferior (AI), posterior superior (PS), posterior inferior (PI), axillary (Ax), and posterolateral alveolar and/or pleural syndrome (PLAPS)

FIGURE 2

(A and B) Relative frequencies of sonographic lung findings and their anatomic distributions based on outcome. Bar heights represent the proportion of subjects that had the finding or region involved. The numbers at the bottom of the bars represent the n involved. Adjacent bars show the outcomes studied from left to right: discharge, admission, ICU use, intubation, and death. Error bars denote the standard error of the proportion. Abbreviation: PLAPS, posterolateral alveolar and/or pleural syndrome

FIGURE 3

Receiver operating characteristic curves of all final models. The color of the line type indicates the outcomes analyzed: intubation (red) and death (black). Binary models are depicted with dashed lines, whereas the scored models with solid lines