Coronavirus disease 2019 (COVID-19, also known as SARS-CoV-2) was declared an official pandemic by the World Health Organization (WHO) on March 11, 2020, with infections reported in all countries around the world. As of today, November 12, 2020, there have been almost 53 million cases of COVID-19 reported worldwide, with over 1.3 million COVID-19-associated deaths.
This pandemic is severe, and the mortality and morbidity associated with this disease cannot be overstated. Although most infected patients are either asymptomatic or experience mild symptoms, a significant number end up in serious or critical condition. This is the patient population that develops a number of complications that affect all body systems, and this group of patients should be very closely monitored in the hospital setting.
Radiology professionals play a significant role in the diagnosis of infected individuals, identification of complications that are not apparent on physical exam or laboratory analysis, and the follow-up imaging assessment of known COVID-related complications. Given that this virus is highly contagious, it became very apparent that safe methods for patient assessment had to be designed and implemented. Ultrasound serves as a first-line imaging modality for evaluation of a number of COVID-19 pathologies and related complications, including evaluation of pulmonary, hepatobiliary, renal, gastrointestinal, and cardiac manifestations. It is the modality of choice in the pediatric population and in pregnant patients. Moreover, ultrasound plays a critical role in the evaluation of patency of peripheral and central vascular systems, including both the arterial and venous circulation as well as solid organ perfusion.
Due to the highly contagious nature of COVID-19, our routine ultrasound radiology practice had to undergo dramatic changes in order to ensure proper infection prevention. We accomplished this through the establishment of control measures and good hygiene practices that were shown to limit spread of COVID‐19 and protect patients, sonographers, and physicians. In addition to following specific guidelines (established at the beginning of the pandemic by the ACR and the SRU) for cleaning and disinfection of ultrasound equipment and use of personal protective equipment (PPE), we also incorporated our own changes that we found to be beneficial in preventing spread of the infection and limiting staff exposure.
At our institution, all patients are considered to be SARS-CoV-2 persons under investigation (PUI), including those without respiratory or digestive symptoms, and appropriate safeguards are taken while performing examinations.
Given the fact that transmission of SARS-CoV-2 occurs primarily through respiratory droplets, fomites, and possibly aerosols, we emphasize the use of portable ultrasound imaging at the patient’s bedside whenever feasible, with the radiology staff wearing appropriate PPE, including an N95 mask, gloves, protective eyewear or an overlying face shield, and a disposable gown.We request that all patients wear surgical masks during the examination.
Equipment must be disinfected after every exposure to COVID-19 positive or suspected positive patients. According to the Centers for Disease Control and Prevention (CDC), surfaces need to be either washed with soap and water or decontaminated using a low-level or intermediate-level disinfectant such as iodophor germicidal detergent solution, ethyl alcohol, or isopropyl alcohol. Vendors should be contacted to determine the safest disinfectant for each piece of equipment. Radiology technologists should perform sanitizing procedures while remaining in full PPE.
It is uncertain how long the air within an examination room remains infectious. Contributing factors likely include the size of the room, the number of air exchanges per hour, the length of time the patient was in the room, type of filters installed in the room, and whether an aerosol-generating procedure was performed. Use of air exchange measures vary depending on the availability of equipment. At our institutions, a 20-minute downtime is mandated for disinfection of the air in an examination room.
The keyboard and monitor of the ultrasound equipment are covered with a plastic drape or cover, and only the required probes are utilized during specific examinations. External transducers require low-level disinfection between procedures, while internal transducers require a single-use transducer cover and high-level disinfection between patients. It should be noted that products that are alcohol-based should be avoided when cleaning keyboards and track balls. If possible, a dedicated machine should be utilized for COVID-positive or suspected-positive patients. The machine should be cleaned with an EPA-approved disinfectant for viral pathogens, by a technologist in full PPE.
One of the primary changes that we implemented within our ultrasound division is the utilization of abbreviated protocols while imaging COVID-19 patients. We found that abbreviated protocols are useful and sufficient for the diagnosis of most COVID-19-related pathologies and complications, and are usually able to provide answers to the questions posed by referring clinicians. We strongly believe that abbreviated protocols have allowed us to decrease technologists’ exposure to the infection and the amount of time spent during imaging exams. When performing ultrasound examinations, we focus only on the area of interest and acquire cine clips rather than still images during the exam. It has also been shown that post processing of images, including image labeling and parameter optimization, significantly decrease the amount of time spent on scanning.
Lastly, it is important to recognize that not every patient benefits from imaging. We carefully review requests for imaging studies with the patient providers and try to weigh the benefits of imaging against the risk of exposure. The guiding principle to keep in mind is that studies don’t need to be performed unless patient management is going to be affected by the imaging findings.
The ultrasound workforce provides a valuable clinical service but is particularly vulnerable because of the prolonged close physical contact between staff and patients. Hopefully, this blog post will serve as a resource to help practitioners improve safety and minimize exposure risk during the performance of ultrasound examinations.
For additional reference:
- Revzin MV, Raza S, Warshawsky R, D’Agostino C, Srivastava NC, Bader AS, Malhotra A, Patel RD, Chen K, Kyriakakos C, Pellerito JS. “Multisystem Imaging Manifestations of COVID-19, Part 1: Viral Pathogenesis and Pulmonary and Vascular System Complications”. RadioGraphics 2020 Oct;40(6):1574–1599. doi: 10.1148/rg.2020200149 Monograph Issue.
- Revzin MV, Raza S, Srivastava NC, Warshawsky R, D’Agostino C, Malhotra A, Bader AS, Patel RD, Chen K, Kyriakakos C, Pellerito JS. “Multisystem Imaging Manifestations of COVID-19, Part 2: From Cardiac Complications to Pediatric Manifestations.” Radiographics 2020 Nov–Dec;40(7):1866–1892. doi: 10.1148/rg.2020200195.
Margarita V. Revzin, MD, MS, FSRU, FAIUM, is an Associate Professor of Diagnostic Radiology in the Department of Radiology and Biomedical Imaging at Yale University School of Medicine, in New Haven, Connecticut.
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