Lung Ultrasound Findings in Patients Hospitalized with Covid-19
1Department of Medicine, Stanford University School of Medicine, Stanford, CA
2Quantitative Sciences Unit, Stanford University, Stanford CA
3Department of Emergency Medicine, Stanford University School of Medicine, Stanford, CA
4Department of Medicine, University of California San Francisco, San Francisco, CA
5Department of Emergency Medicine, University of California San Francisco, San Francisco, CA
*Corresponding Author: Andre Kumar, MD, MEd, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 95401, Akumar3@stanford.edu, Phone-650-723-2300Abstract
Introduction
Point-of-care ultrasound (POCUS) has the potential to transform healthcare delivery in the era of COVID-19 with its diagnostic and therapeutic expediency. It can be performed by clinicians already at the bedside, which permits an immediate and augmented assessment of a patient. Although lung ultrasound can be used to accurately diagnose a variety of disease states such as pneumothorax, pleural effusions, pneumonia and interstitial lung disease2, there are limited reports on the sonographic manifestations of COVID-19. There is an urgent need to identify alternative diagnostic modalities that can be immediately employed at the bedside of COVID-19 patients.
Methods
This study was conducted at two medical centers in the United States from 3/21/2020-6/01/2020. Any adult who was hospitalized with COVID-19 (based on symptomatology and a confirmatory RT-PCR for SARS-CoV-2) and received a pulmonary POCUS examination was included. Providers were instructed to use a 12-zone scanning protocol for pulmonary views and save 6 second clips of each lung zone. This study utilized several POCUS devices, including Butterfly IQ, Vave, Lumify, and Sonosite. The collected images were interpreted by the study researchers based on a consensus document developed by the study authors and previously accepted definitions of lung POCUS findings.
Results
A total of 22 eligible patients who received 36 lung scans were included in our study. Eleven (50%) patients experienced clinical deterioration (defined as either ICU admission, invasive mechanical ventilation, or death within 28 days from the initial symptom onset). Among the 36 lung scans collected, only 3 (8%) were classified as normal. The remaining scans had the following abnormalities: presence of B-lines (n=32, 89%), consolidations (n=20, 56%), pleural thickening (n=17, 47%), and pleural effusion (n=4, 11%). Out of 20 scans with consolidations, 14 (70%) were subpleural and 5 (25%) were translobar. A-lines were present in 26 (72%) of patients, although they were only observed in the majority of the collected lung zones in 5 (14%) of patients. Ultrasound findings were stratified by time from symptom onset to the scan based on the following time periods: early (0-6 days), middle (7-13 days), and late (14-28 days). B-lines appeared early after symptom onset and persisted well into the late disease course. In contrast, pleural thickening increased in frequency over time (early: 25%, middle: 47%, late: 67%). Subpleural consolidations also appeared in higher frequency later in the disease course (early: 13%, middle 42%, late: 56%).
Discussion
certain lung ultrasound findings may be common in Covid-19, while others may appear later in the disease course or only occur in patients who experience clinical deterioration. Future efforts should investigate the predictive utility of consolidations, pleural thickening and B-lines for clinical deterioration and compare them to traditional radiological studies such as X-rays or CTs.
Article notes
Competing Interest Statement
Andre Kumar, MD, MEd is a paid consultant for Vave Health, which manufactures one of the ultrasound devices used in this study. His consultant duties include providing feedback on product development. The other authors do not have any items to disclose.
Clinical Trial
NCT04384055
Funding Statement
This research was not funded by a private or governmental body.
Introduction
Point-of-care ultrasound (POCUS) has the potential to transform healthcare delivery in the era of COVID-19 with its diagnostic and therapeutic expediency.1 It can be performed by clinicians already at the bedside, which permits an immediate and augmented assessment of a patient.2 POCUS devices, particularly handheld devices, are often cheaper than traditional radiological equipment such as X-ray or computerized tomography (CT) machines, which makes POCUS ideal for surge scenarios and other resource-limited settings. Since providers using POCUS are concomitantly at the bedside assessing patients, POCUS may reduce personal protective equipment usage by radiological technicians or the need to decontaminate larger radiological equipment.
Although lung ultrasound can be used to accurately diagnose a variety of disease states such as pneumothorax, pleural effusions, pneumonia and interstitial lung disease2, there are limited reports on the sonographic manifestations of COVID-19. There is an urgent need to identify alternative diagnostic modalities that can be immediately employed at the bedside of COVID-19 patients. In this report, we characterize lung ultrasound findings of patients admitted to our hospitals with COVID-19 and stratify these findings by time, location, and illness severity.
Methods
This study was conducted at two medical centers in the United States from 3/21/2020-6/01/2020. Any adult who was hospitalized with COVID-19 (based on symptomatology3 and a confirmatory RT-PCR for SARS-CoV-2) and received a pulmonary POCUS examination was included. Patients who did not meet these criteria were excluded. Our Institutional Review Board approved this study.
Provider discretion determined whether to perform an initial or follow-up POCUS examination for each patient. Providers were instructed to use a 12-zone scanning protocol for pulmonary views (Figure 1) and save 6 second clips of each lung zone.4 This study utilized several POCUS devices, including Butterfly IQ™, Vave™, Lumify™, and Sonosite™. The collected images were interpreted by the study researchers based on a consensus document developed by the study authors and previously accepted definitions of lung POCUS findings.4-7
Results
A total of 22 eligible patients who received 36 lung scans were included in our study (Table 1). Eleven (50%) patients experienced clinical deterioration (defined as either ICU admission, invasive mechanical ventilation, or death within 28 days from the initial symptom onset).
Among the 36 lung scans collected, only 3 (8%) were classified as normal (Table 1). The remaining scans had the following abnormalities: presence of B-lines (n=32, 89%), consolidations (n=20, 56%), pleural thickening (n=17, 47%), and pleural effusion (n=4, 11%). Out of 20 scans with consolidations, 14 (70%) were subpleural and 5 (25%) were translobar. A-lines were present in 26 (72%) of patients, although they were only observed in the majority of the collected lung zones in 5 (14%) of patients. Table 1 also displays the above findings by location.
Scans from patients who experienced clinical deterioration demonstrated higher percentages of B-lines (100% vs. 80%), consolidations (69% vs. 45%), pleural thickening (69% vs. 30%) and effusions (25% vs. 0%). Additionally, scans from patients with clinical deterioration had higher percentages of bilateral B-lines (63% vs. 45%) and bilateral consolidation (50% vs. 15%).
Ultrasound findings were stratified by time from symptom onset to the scan based on the following time periods: early (0-6 days), middle (7-13 days), and late (14-28 days). B-lines appeared early after symptom onset and persisted well into the late disease course (Figure 2). In contrast, pleural thickening increased in frequency over time (early: 25%, middle: 47%, late: 67%). Subpleural consolidations also appeared in higher frequency later in the disease course (early: 13%, middle 42%, late: 56%). A-lines were observed throughout the time course (early: 63%, middle 74%, late 78%; Figure 2), although A-lines often occurred in a patchy distribution.
Discussion
In this report, we characterize lung ultrasound findings for patients admitted to the hospital with COVID-19, and further stratify these findings by patients who experienced clinical deterioration. Common findings included B-lines, consolidation (including subpleural consolidations), and pleural thickening. Effusions were rare, which is consistent with CT studies from COVID-19 patients.5 Notably, B-lines were common for both patients who did and did not experience clinical deterioration. They frequently appeared in all lung zones, and they persisted throughout the 28 day scanning period. In contrast, subpleural consolidation and pleural thickening appeared later in the disease course, and they were more common in patients who experienced clinical deterioration. Importantly, bilateral involvement of several findings (B-lines or consolidation) was more commonly encountered in the patients who experienced clinical deterioration. Certain patient conditions, such as intubation or patient mobility, affected the provider from acquiring all 12 zones, particularly the posterior zones.
In conclusion, certain lung ultrasound findings may be common in Covid-19, while others may appear later in the disease course or only occur in patients who experience clinical deterioration. Future efforts should investigate the predictive utility of consolidations, pleural thickening and B-lines for clinical deterioration and compare them to traditional radiological studies such as X-rays or CTs.
Data Availability
All summary data are available to individuals who request it. We cannot share data that contains PHI.