key: cord-0895907-d6yyryw9
authors: Abrams, Eric R.; Rose, Gabriel; Fields, J. Matthew; Esener, Dasia
title: Clinical Review: Point-of-Care Ultrasound in the Evaluation of COVID-19
date: 2020-06-12
journal: J Emerg Med
DOI: 10.1016/j.jemermed.2020.06.032
sha: f0615e8ede3672503bdc7f016d77e26fd613ff90
doc_id: 895907
cord_uid: d6yyryw9

Abstract The novel coronavirus SARS-CoV-2 has caused a pandemic overwhelming healthcare systems around the world. Hospitals around the world, including the United States, have been struggling to adapt to the influx of patients with COVID-19, the illness caused by SARS-CoV2, given limited resources and high demand for medical care. Point of care ultrasound provides numerous benefits to emergency providers caring for patients with COVID-19 including decreasing resource utilization, assisting in diagnosis, guiding management of the critically ill patient, and aiding in rapid triage of patients under investigations for COVID-19. The studies currently being published have established a typical set of ultrasound findings in COVID-19. Point of care lung ultrasound is rapid and accessible in most emergency departments in the United States and even if many resource-poor settings. This article seeks to provide emergency physicians with a guide to sonographic findings in COVID-19 and an algorithm by which point of care lung ultrasound may assist emergency physicians caring for these patients during the SARS-CoV-2 pandemic.

(ED) is an inevitability for many hospital systems. This anticipated influx in ED volume of PUIs 23 presents unique challenges to the ED workflow. Clinical presentations of COVID-19 can vary 24 from mild or asymptomatic to critical with acute respiratory failure. As a result, many EDs are 25 erecting disaster tents outside of their main ED for rapid triage, segregation away from non-PUI 26 ED patients, and disposition of well appearing patients, in addition to expanding their ability to 27 care for intubated patients. While standard imaging techniques will undoubtedly be employed, 28 point-of-care ultrasound (POCUS) offers a unique strategy for the diagnosis and risk 29 stratification of COVID-19 without utilizing significant ED resources. Currently there is no consensus on the most appropriate method of ultrasound imaging 49 the PUI population. Although the Volpicelli 8-view approach can be performed 4 , one small study 50 of patients with COVID-19 undergoing computed tomography imaging found that the right 51 lower lobe was the most sensitive for pathology. In addition, the posterior lung was involved in 52 67% of cases 5 . Another study of 20 patients with COVID-19 undergoing POCUS imaging found 53 that most lung pathology was found primarily in the posterior lung bases 1 . Therefore, scanning 54 the posterior lungs should be prioritized in any lung ultrasound imaging protocol. To obtain the 55 best image quality for the assessment of COVID-19 lung pathology, it is also recommended that 56 a high frequency linear array transducer or a curvilinear transducer be used 1,3,6 . 57 58

There have also been numerous reports of COVID-19-related myocarditis and myocardial 60 injury 7-10 . Although the true incidence of COVID-19 myocarditis is unknown, one study found 61 the incidence of arrhythmia was 16.7%, and acute cardiac injury was 7.2% 10 . Another COVID-62 19 study found that in a series of twenty-one critically ill ICU patients, one-third developed 63 cardiomyopathy 12 . Not all PUIs presenting with respiratory complaints are necessarily linked to 64 COVID-19. Rather, some patients may present with acute heart failure exacerbation, myocardial 65 infarction, valvular disease, pulmonary embolus, or pericardial tamponade. Therefore, in 66 addition to lung ultrasound, a focused cardiac ultrasound should be considered in the PUI 67 population, and is strongly encouraged in any critically ill PUI.

Since the volume of PUIs will likely increase over the coming weeks, lung ultrasound has 71 the potential to become a tool for risk stratification for several reasons. First, lung ultrasound has 72

shown strong evidence that it has non-inferior or superior accuracy compared to chest X-ray 73 (CXR) for many of the most common causes of dyspnea 13-14 . Although CXR imaging is 74 appropriate for the evaluation of lung pathology in COVID-19, up to 18% of patients have a 75 normal initial CXR 15 . In addition, a study of patients with a diagnosis of either bacterial 76 pneumonia or H1N1 pneumonia who underwent lung ultrasound imaging found that bedside 77 chest US provided early detection of interstitial involvement in H1N1 pneumonia even when the 78 CXR was normal 16 . It is therefore reasonable to assume that lung ultrasound may have an 79 equivalent or higher sensitivity for detecting lung pathology compared to CXR imaging. If a PUI 80 can avoid CXR, a decrease in radiology resources would likely provide substantial 81 improvements in time to discharge and a decrease in exposure of staff and other patients to PUIs. 82

Ultrasound can also theoretically be used to monitor disease progression. Although no current 83 studies are available, the generally accepted disease progression of COVID-19 is normal lung 84 parenchyma, to scattered B-lines, to confluent B-lines with consolidation. Thus, lung ultrasound 85 could be used for reassessment, or even shed light onto COVID-19 disease staging. 86

We propose an algorithm that utilizes lung ultrasound as a screening tool to risk stratify 87

PUIs into low and high-risk categories ( Figure 5 ). Low-risk patients (well appearing, reassuring 88 vital signs) will most likely be discharged from the ED. Many of these low-risk patients will 89 have some facet of respiratory symptoms that may invoke a provider to order a radiology study, 90 specifically CXR. Utilization of lung ultrasound in low-risk PUIs may therefore be considered to decrease the use of radiology resources. Should a low-risk PUI have lung ultrasound findings 92 indicative of advanced disease, the PUI may need further work-up including chest radiograph 93 imaging or reassessment for proper disposition. In high-risk PUIs (respiratory distress or grossly 94 abnormal vital signs) ultrasound can help determine how far a patient's disease has progressed 95 and also assess for myocardial dysfunction. Again, the poor sensitivity of CXR imaging and the 96 risk of nosocomial infection to other patients and hospital staff should be considered for all PUIs. 97

If lung ultrasound is performed and advanced disease (i.e. confluent b-line pattern, 98 consolidation) is appreciated, the PUI may be at markedly increased risk of decompensation. 99

Given the significant amount of myocardial disease in critically ill patients with COVID-19, 100

focused cardiac ultrasound should also be used in all high-risk patients. 101

Although ultrasound is generally associated with few risks, the PUI patient population is 104 unique in that providers performing POCUS may have prolonged close contact with the patient. 105

It should be stated that the current recommendation from the CDC is to prioritize N95 respirators 106 for aerosol-generating procedures (e.g. intubation, bronchoscopy) 17 . Since POCUS does not 107 qualify as an aerosol-generating procedure, surgical masks can be used as personal-protective 108 equipment. Notwithstanding, since minimizing PUI contact is always preferred, POCUS should 109 only be performed if it may change clinical decision-making. 110

Ultrasound machines can also be exposed to respiratory droplets from PUI after 111 prolonged contact. A recent article stated viable SARS-CoV-2 can remain on fomites for up to 112 72 hours 18 . Strict disinfection control should be maintained. For POCUS cart-based machines, a 113 large plastic equipment cover can be placed over the machine and exchanged between patients ( Figure 6 ). In addition, using disposable ultrasound transducer covers between exams can be 115 used to avoid contaminating the transducer. After use, the machine and transducer should be 116 disinfected using a product approved by the EPA for SARS-CoV2. A full list can be found at the 117 EPA website -https://www.epa.gov/pesticide-registration/list-n-disinfectants-use-against-sars-118 cov-2. 119

The disinfection of hand-held portable ultrasound machines may be less cumbersome. 120

These machines may be able to fit entirely in a sterile transducer cover and closed off to the 121 external environment (Figure 6 ). After use, the apparatus can be removed and more easily 122 cleaned with an EPA approved disinfectant. Figure 6 Large plastic equipment cover over POCUS cart-based machine (A) with disposable ultrasound probe over phased-array ultrasound probe (B). Disposable ultrasound probe cover encompassing the entirety of a hand-held portable ultrasound (C).

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COVID-19)

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