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ACEP COVID-19 Field Guide

Table of Contents

Ultrasound

Assessment

Authors: Gillian Baty, MD, MPH, Residency Program Director, former EM Ultrasound Director, Professor, Department of Emergency Medicine, University of New Mexico; and Nova Panebianco, MD, MPH, EM Ultrasound Division Director, Ultrasound Fellowship Director, Associate Professor, Department of Emergency Medicine, University of Pennsylvania

For patients with a suspected COVID-19 infection, ultrasound has several applications that are particularly useful for diagnosing common complications of the illness. Point-of-care (POCUS), or clinician-performed, ultrasound is often a better diagnostic modality because it allows for efficient evaluation while minimizing staff and facility exposure to infectious agents. Some sonographic patterns in COVID-19 patients may be better detected and managed with POCUS. All these sonographic patterns widely overlap with other conditions, limiting their specificity. POCUS may be particularly useful when rapid COVID-19 testing or other resources are limited, patient volumes outstrip an institution’s resources, serial examinations are desirable for monitoring disease progression, ionized radiation in testing needs to be limited, or patients are too unstable to have imaging beyond the bedside.

The following four categories of POCUS for COVID-19 infection have been most discussed in the ultrasound community:

  1. Lung. COVID-19 disease is most often associated with pulmonary manifestations, which predominate in severe presentations. Lung ultrasound has good evidence to evaluate for interstitial lung water or congestion, consolidation, pneumothorax, and pleural effusion.
  2. Cardiac. Cardiac manifestations may cause severe clinical phenotypes or adverse events, so cardiac ultrasound, or transthoracic echocardiography (TTE), has been used to evaluate for global cardiomyopathy, regional wall motion abnormalities, and pulmonary embolism.
  3. Deep vein thrombosis. Severe infection is characterized by a proinflammatory state that induces procoagulant, positive feedback loops. COVID-19–associated venous thromboembolism is associated with high morbidity and mortality. POCUS for deep vein thrombosis has been validated to have high sensitivity and specificity when done by emergency physicians, even those who have minimal training. 
  4. General procedural. Patients with severe COVID-19 disease often require several invasive procedures. POCUS has been shown to decrease complications and increase the success of several key invasive procedures; it also has fewer infection control implications than imaging suites.

Lung ultrasound

Prior to the pandemic, lung ultrasound had reasonable evidence for better sensitivity than plain x-rays for consolidation, interstitial edema, and pneumothorax, all common findings in COVID-19–related pneumonia.1-3 Since the start of the pandemic, the literature increasingly supports lung ultrasound as an adjunct diagnostic modality for both the diagnosis and prognosis of disease. Current best practice is to scan multiple lung fields and assign a score of 0 to 3 for each field based on a combination of ultrasound findings to create an overall severity score.4 Higher scores correlate with higher sensitivity and increasing disease severity.5 An alternative technique of sweeping relatively rapidly through multiple lung zones has been proposed as both a more efficient technique and a more forgiving method for less skilled sonographers.6 Posterior lung fields, which are not always part of a standard lung ultrasound protocol, may be positive more often in COVID-19 patients, and the presence of positive posterior lung fields may guide specific treatment (eg, pronation).5 Lung ultrasound has high predictive relevance in clinical outcomes and the need for invasive mechanical ventilation and has high diagnostic accuracy for interstitial pneumonia. Lung ultrasound phenotypes have good predictive value in the diagnosis of pulmonary COVID-19 compared to real-time RT-PCR COVID-19 testing.5,7,8

The current best evidence for lung ultrasound in COVID-19 disease supports its use in evaluating for:

  • Interstitial lung water (B-lines)
    • At least three
    • Confluent
  • Subpleural consolidations
  • Thickened or irregular pleural line
  • Pleural effusions (rare)

Cardiac ultrasound

Although there is a clear association between cardiovascular disease and COVID-19, the data on echocardiographic findings and their significance in COVID-19 disease are more scarce and heterogeneous. The utility of POCUS TTE was recognized early, and the American Society of Echocardiography recommends POCUS for early identification of worsening cardiac function, for monitoring, and for identification of associated cardiovascular abnormalities such as pericardial effusion, left ventricular systolic dysfunction, and pulmonary embolism.9,10

A joint position statement, including input from the American College of Emergency Physicians, states: “Cardiovascular manifestations of COVID-19 are complex, with patients presenting with acute myocardial infarction, myocarditis simulating an ST-elevation myocardial infarction (STEMI) presentation, stress cardiomyopathy, nonischemic cardiomyopathy, coronary spasm, or nonspecific myocardial injury.”11 For these reasons and more, there was concern during the pandemic that infection would spread through the facility from staff and equipment.

POCUS — with handheld devices that provide remarkable imaging for their size — became especially attractive during the pandemic as an imaging modality that reduced the chance of infection spreading. Many emergency physicians are familiar with limited echocardiography for global left ventricular assessment, pericardial effusion, and chamber enlargement; comprehensive echocardiogram that includes assessment for focal wall motion abnormalities, valvular dysfunction, diastolic dysfunction, or right ventricular dysfunction is often outside the scope of emergency medicine. An abnormal echocardiogram, especially one that shows severe left ventricular dysfunction, has been associated with worse outcomes in COVID-19 patients. The rate of cardiac abnormalities in hospitalized COVID-19 patients during the pandemic was up to 68%. Up to nearly one-third of identified abnormalities led to management change.12-14

The current best evidence for POCUS limited echocardiography in COVID-19 disease supports its use in evaluating for:

  • Reduced systolic function
    • Evidence suggests that some patients with severe COVID-19 infection develop cardiomyopathy, especially those with preexisting cardiovascular disease.15 It is unclear if this finding represents viral cardiomyopathy, is stress induced, or is secondary to cytokine storm. Left ventricular systolic dysfunction is a less common finding in COVID-19 patients, but severe left ventricular dysfunction is associated with mortality.16
  • Pericardial effusion
    • The extent of pericardial involvement in COVID-19 disease is unknown. Pericardial effusion or tamponade may be higher in COVID-19 patients than in other critically ill patients.17 This condition should be considered in any critically ill patient with suspected pericarditis or unexplained hypotension. The decision to obtain a comprehensive vs a POCUS limited echocardiogram will likely vary by institutional practice and culture. Having POCUS images available for consultant review may limit unnecessary additional testing.
  • Right ventricular dilatation
    • Some patients with severe COVID-19 infection develop a prothrombotic state that can cause deep vein thrombosis and pulmonary embolism. Although emergency physicians can assess for right heart strain, assessing whether the condition is acute or chronic is more challenging. A baseline POCUS echocardiogram at the time of admission should be considered because the development of right heart strain in a patient who did not have it earlier can assist in the diagnosis of right ventricular dilatation.

Deep vein thrombosis

The prothrombotic state induced by COVID-19 puts patients at risk of deep vein thrombosis and pulmonary embolism, above the standard risk from hospitalization and immobility. A 2020 screening study of 234 hospitalized COVID-19 patients showed that these patients had an overall deep vein thrombosis rate of 10.7%, with an even higher incidence of 13.8% in those who had severe COVID-19 disease.18

In one study, a rapidly rising D-dimer level was a predictor of COVID-19–associated disseminated intravascular coagulation, and patients with a D-dimer level over 1,000 ng/mL were 20 times more likely to die than patients with levels below this threshold.19

Deep vein thrombosis prophylaxis should be maintained in COVID-19 patients if there are no contraindications; these patients may need higher doses of prophylactic heparin. Therapeutic anticoagulation with heparin for patients with D-dimer levels over 200 ng/mL has been suggested but is unproven.20

Emergency physician–performed two-point (popliteal and common femoral veins) or three-point (including femoral vein) POCUS of the lower extremity for deep vein thrombosis has been shown to have very high specificity and sensitivity.18,21 The current best evidence supports two- or three-point POCUS to evaluate for deep vein thrombosis.

Procedural guidance

POCUS for procedural guidance is the standard of care for many invasive actions and has been shown to decrease complications and increase the success of procedures. Additionally, POCUS can be used to identify complications when they do happen (eg, pneumothorax, vascular misplacement, vascular injury, and so on). Severe COVID-19 disease likely requires several procedures including, but not limited to, peripheral venous access, central venous access, arterial lines, thoracentesis, paracentesis, and intubation. Multiple meta-analyses have shown that POCUS has a pooled sensitivity of up to 98.7% and a specificity of 95% to 97% for confirming correct placement of endotracheal tubes, with a mean confirmation time of 13 seconds. The standard of care for confirmation, however, is chest x-ray.22,23

Infection control

To control infection, the exclusive use of handheld ultrasound devices for patients with suspected or confirmed COVID-19 should be considered. These ultra-portable devices are easier to cover and clean than cart-based devices. However, drawbacks of POCUS include a small screen, difficulty finding a place to put the screen during a procedure, and in some cases, inferior image quality compared to cart-based machines. For some patients and conditions, certain features of cart-based machines (eg, spectral Doppler) may be necessary over the portability and ease of disinfection of handheld devices.

Excerpt from the ACEP Ultrasound Section COVID-19 Town Hall

Author: Rachel Liu, MD, FACEP, FAIUM, Associate Professor of Emergency Medicine, Yale School of Medicine

POCUS of the lung utilizes artifacts and findings at the lung periphery and has been shown to identify heart failure, acute respiratory distress syndrome, and pneumonia. Lung ultrasound findings in a series of 20 patients with COVID-19 included thickening and irregularity of the pleural line, a variety of B-line patterns, and subpleural consolidations. Pleural effusions were rare.24

A recent letter in Radiology reported that ultrasound in 12 patients with 4 to 10 days of COVID-19 infection without severe respiratory illness displayed a “diffuse B-pattern with spared areas.” The authors “strongly recommend the use of bedside ultrasound for the early diagnosis of COVID-19 pneumonia.”25 Although these results are preliminary, they suggest ultrasound findings in COVID-19 are likely more common than findings on plain chest x-ray and may be characteristic of COVID-19.

Other POCUS applications like cardiac and vascular ultrasound are also helpful in disease detection and treatment of COVID-19 patients. For more information, refer to the “ASE Statement on Point-of-Care Ultrasound (POCUS) During the 2019 Novel Coronavirus Pandemic.”

Since 2020, a meta-analysis confirmed that B-lines, confluent B-lines, and pleural (subpleural) abnormalities are the most common ultrasound lung findings for COVID-19, while pulmonary consolidation and pleural effusions are infrequent findings.26

References

  1. Chavez MA, Shams N, Ellington LE, et al. Lung ultrasound for the diagnosis of pneumonia in adults: a systematic review and meta-analysis. Respir Res. 2014;15:50. doi: 10.1186/1465-9921-15-50
  2. Al Deeb M, Barbic S, Featherstone R, Dankoff J, Barbic D. Point-of-care ultrasonography for the diagnosis of acute cardiogenic pulmonary edema in patients presenting with acute dyspnea: a systematic review and meta-analysis. Acad Emerg Med. 2014 Aug;21(8):843-852. doi: 10.1111/acem.12435
  3. Ding W, Shen Y, Yang J, He X, Zhang M. Diagnosis of pneumothorax by radiography and ultrasonography: a meta-analysis. Chest. 2011 Oct;140(4):859-866. doi: 10.1378/chest.10-2946
  4. Soldati G, Smargiassi A, Inchingolo R, et al. Proposal for international standardization of the use of lung ultrasound for patients with COVID-19. J Ultrasound Med. 2020 Jul;39(7):1413-1419. doi: 10.1002/jum.15285
  5. Gil-Rodríguez J, Pérez de Rojas J, Aranda-Laserna P, et al. Ultrasound findings of lung ultrasonography in COVID-19: a systematic review. Eur J Radiol. 2022 Mar;148:110156. doi: 10.1016/j.ejrad.2022.110156
  6. Olusanya O, Baston C. Lung ultrasound in COVID-19: sweeping the surface or sounding the depths. Chest. 2023 Jan;163(1):12-13. doi: 10.1016/j.chest.2022.08.2226
  7. Volpicelli G, Fraccalini T, Cardinale L, et al. Feasibility of a new lung ultrasound protocol to determine the extent of lung injury in COVID-19 pneumonia. Chest. 2023 Jan;163(1):176-184. doi: 10.1016/j.chest.2022.07.014
  8. Volpicelli G, Gargani L, Perlini S, et al. Lung ultrasound for the early diagnosis of COVID-19 pneumonia: an international multicenter study. Intensive Care Med. 2021 Mar 20;47:444-454. doi: 10.1007/s00134-021-06373-7
  9. Zhang L, Wang B, Zhou J, Kirkpatrick J, Xie M, Johri AM. Bedside focused cardiac ultrasound in COVID-19 from the Wuhan epicenter: The role of cardiac point-of-care ultrasound, limited transthoracic echocardiography, and critical care echocardiography. J Am Soc Echocardiogr. 2020 Jun;33(6):676-682. doi: 10.1016/j.echo.2020.04.004
  10. Johri A, Galen B, Kirkpatrick JN, Lanspa M, Mulvagh S, Thamman R. ASE statement on point-of-care ultrasound during the 2019 novel coronavirus pandemic. J Am Soc Echocardiogr. 2020 Jun;33(6):670-673. doi: 10.1016/j.echo.2020.04.017
  11. Mahmud E, Dauerman H, Welt F, et al. Management of acute myocardial infarction during the COVID-19 pandemic: a position statement from the Society for Cardiovascular Angiography and Interventions (SCAI), the American College of Cardiology (ACC), and the American College of Emergency Physicians (ACEP). J Am Coll Cardiol. 2020 Sep;76(11):1375-1384. doi: 10.1016/j.jacc.2020.04.039
  12. Szekely Y, Lichter Y, Taieb P, et al. Spectrum of cardiac manifestations in COVID-19: a systematic echocardiographic study. Circulation. 2020 Jul 28;142(4):342-353. doi: 1161/CIRCULATIONAHA.120.047971
  13. Dadon Z, Carasso S, Gottlieb S. The role of hand-held cardiac ultrasound in patients with COVID-19. Biomedicines. 2023;11(2):239. doi: 10.3390/biomedicines11020239
  14. Baloescu C, Weingart G, Moore C. Emergency department point-of-care echocardiography and lung ultrasound in predicting COVID-19 severity. J Ultrasound Med. 2023 Feb 25;42(8):1841-1850. doi: 10.1002/jum.16205
  15. Li Y, Fang L, Zhu S, et al. Echocardiographic characteristics and outcome in patients with COVID-19 infection and underlying cardiovascular disease. Cardiovasc Med. 2021 Mar 16;8:642973. doi: 3389/fcvm.2021.642973
  16. Havaldar A, Kumar M, Kumar R, et al. Echocardiographic parameters in COVID-19 patients and their association with ICU mortality: a prospective multicenter observational study. Ultrasound J. 2023 Sep 13;15(1):38. doi: 10.1186/s13089-023-00336-3
  17. Ghantous E, Szekely Y, Lichter Y, et al. Pericardial involvement in patients hospitalized with COVID‐19: prevalence, associates, and clinical implications. JAHA. 2022 Apr 5;11(7):e024363. doi: 10.1161/JAHA.121.024363
  18. Ierardi A, Coppola A, Fusco S, et al. Early detection of deep vein thrombosis in patients with coronavirus disease 2019: who to screen and who not to with Doppler ultrasound? J Ultrasound. 2021 Jun;24(2):165-173. doi: 10.1007/s40477-020-00515-1
  19. Zhou F, Yu T, Du R, et al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. Lancet. 2020 Mar 28;395(10229):1054-1062. doi: 10.1016/S0140-6736(20)30566-3
  20. Tang N, Bai H, Chen X, Gong J, Li D, Sun Z. Anticoagulant treatment is associated with decreased mortality in severe coronavirus disease 2019 patients with coagulopathy. Thromb Haemost. 2020 May;18(5):1094-1099. doi:10.1111/jth.14817
  21. Lee JH, Lee SH, Yun SJ. Comparison of 2-point and 3-point point-of-care ultrasound techniques for deep vein thrombosis at the emergency department: a meta-analysis. Medicine (Baltimore). 2019 May;98(22):e15791. doi: 10.1097/MD.0000000000015791
  22. Gottlieb M, Holladay D, Peksa G. Ultrasonography for the confirmation of endotracheal tube intubation: a systematic review and meta-analysis. Ann Emerg Med. 2018 Dec;72(6):627-636. org/10.1016/j.annemergmed.2018.06.024
  23. Li X, Zhang J, Karunakaran M, Hariharan VS. Diagnostic accuracy of ultrasonography for the confirmation of endotracheal tube intubation: a systematic review and meta-analysis. Med Ultrason. 2023 Mar 30;25(1):72-81. doi: 10.11152/mu-3594
  24. Huang Y, Wang S, Liu Y, et al. A preliminary study on the ultrasonic manifestations of peripulmonary lesions of non-critical novel coronavirus pneumonia (COVID-19). Published February 26, 2020. doi: 10.2139/ssrn.354750
  25. Poggiali E, Dacrema A, Bastoni D, et al. Can lung US help critical care clinicians in the early diagnosis of novel coronavirus (COVID-19) pneumonia? Radiology. 2020 Mar 13;295(3). doi: 10.1148/radiol.2020200847
  26. Gil-Rodriguez J, Perez de Rojas J, Aranda-Laserna P, et al. Ultrasound finding of lung ultrasonography in COVID-19: a systematic review. Eur J Radiol. 2022 Mar;148:110156. doi: 10.1016/j.ejrad.2022.110156

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