Prevalence and significance of pulmonary disease on lung ultrasonography in outpatients with SARS-CoV-2 infection

Abstract

Background: The majority of patients with SARS-CoV-2 infection are diagnosed and managed as outpatients; however, little is known about the burden of pulmonary disease in this setting. Lung ultrasound (LUS) is a convenient tool for detection of COVID-19 pneumonia. Identifying SARS-CoV-2 infected outpatients with pulmonary disease may be important for early risk stratification.

Objectives: To investigate the prevalence, natural history and clinical significance of pulmonary disease in outpatients with SARS-CoV-2.

Methods: SARS-CoV-2 PCR positive outpatients (CV(+)) were assessed with LUS to identify the presence of interstitial pneumonia. Studies were considered positive based on the presence of B-lines, pleural irregularity and consolidations. A subset of patients underwent longitudinal examinations. Correlations between LUS findings and patient symptoms, demographics, comorbidities and clinical outcomes over 8 weeks were evaluated.

Results: 102 CV(+) patients underwent LUS with 42 (41%) demonstrating pulmonary involvement. Baseline LUS severity scores correlated with shortness of breath on multivariate analysis. Of the CV(+) patients followed longitudinally, a majority showed improvement or resolution in LUS findings after 1-2 weeks. Only one patient in the CV(+) cohort was briefly hospitalised, and no patient died or required mechanical ventilation.

Conclusion: We found a high prevalence of LUS findings in outpatients with SARS-CoV-2 infection. Given the pervasiveness of pulmonary disease across a broad spectrum of LUS severity scores and lack of adverse outcomes, our findings suggest that LUS may not be a useful as a risk stratification tool in SARS-CoV-2 in the general outpatient population.

Keywords: COVID-19; imaging/CT MRI etc; pneumonia.

Figure 1

Baseline lung ultrasound results, features and severity for SARS-CoV-2 PCR positive patients.

Figure 2

(A) LUS of a healthy individual showing ribs (r) and pleural surface (p). (B) LUS (left panel) and CT imaging (right panel) of the left lung in a CV(+) outpatient at follow-up (patient 16) showing B-lines (arrows) and pleural irregularity (dotted circle) and location of LUS findings on corresponding CT imaging (black arrowhead) with corresponding reticulation and mild ground-glass reflecting mild fibrosis. This was ultimately felt to be due to pre-existing interstitial lung abnormality versus postpneumonia sequelae from SARS-CoV-2 infection (C) LUS (left and middle panels) and CT imaging (right panel) of the left lung in a CV(+) outpatient (patient 87) at baseline showing small subpleural consolidations (grey arrowheads) and corresponding peripheral ground-glass and consolidations typical for SARS-CoV-2 pneumonia on CT imaging (black arrowhead). CV(+), SARS-CoV-2 PCR positive; LUS, lung ultrasound.

Figure 3

This figure includes only patients with follow-up LUS evaluations. Patient number is shown for select patients. Open diamond=baseline LUS severity score 0; closed circle=baseline LUS severity score >0; dotted line=increasing or same score at follow-up examination; solid line=improved score at follow-up examination. LUS, lung ultrasound.