POCUS in COVID-19: pearls and pitfalls
Authors: Jonathan Chun-Hei Cheung, Koon Ngai Lam
Journal: The Lancet Respiratory Medicine (2020)

Danilo Buonsenso and colleagues1Buonsenso D Pata D Chiaretti A COVID-19 outbreak: less stethoscope, more ultrasound.Lancet Respir Med. 2020; (published online March 20.)https://doi.org/10.1016/S2213-2600(20)30120-XSummary Full Text Full Text PDF PubMed Scopus (259) Google Scholar described in their Correspondence how lung ultrasound could replace stethoscopes in the ongoing coronavirus disease 2019 (COVID-19) pandemic, which could possibly reduce the risk of exposure.1Buonsenso D Pata D Chiaretti A COVID-19 outbreak: less stethoscope, more ultrasound.Lancet Respir Med. 2020; (published online March 20.)https://doi.org/10.1016/S2213-2600(20)30120-XSummary Full Text Full Text PDF PubMed Scopus (259) Google Scholar Indeed, point-of-care ultrasound (POCUS) has an exemplary role in many specialties, especially emergency and critical care medicine. Nevertheless, this technology is still relatively new so we would like to highlight the pearls and pitfalls for POCUS users to use this tool to its full potential and ensure optimal patient care and safety. There should be dedicated machines for patients with COVID-19. Nowadays, many handheld models are affordable even for low-resource regions and some can cost only one twentieth of an ordinary mid-range or high-end machine. In the intensive care unit (ICU), if the department can afford the expense, it is optimal to assign one machine to each ICU patient, similar to common practice of avoiding cross-contamination by allocating a single stethoscope at the bedside for each individual patient. Another measure to minimise the possibility of cross-contamination is to use individually packaged, single-use ultrasound gel. There are several features clinicians should look for when selecting the ideal pocket machine. First, wireless models are better than those with a cable because they are easier to manipulate (even if put in a plastic probe cover) and remove the risk of the cable contacting the surrounding environment. Second, machines that can be wirelessly charged are preferable because they obviate the need of removing the plastic cover unnecessarily for recharging. Third, the devices that possess multiple probe functionalities in a single unit are desirable because they can be used to do various clinical tasks without additional tools—eg, for patients with COVID-19 who require central venous catheter insertion as part of shock management, bedside cardiac ultrasound to assess ventricular function due to the risk of myocarditis,2Driggin E Madhavan MV Bikdeli B et al.Cardiovascular considerations for patients, health care workers, and health systems during the coronavirus disease 2019 (COVID-19) pandemic.J Am Coll Cardiol. 2020; (published online March 19.)DOI:10.1016/j.jacc.2020.03.031Crossref PubMed Scopus (1445) Google Scholar or have acute pulmonary heart disease from their demand of higher positive end-expiratory pressure. Lung ultrasound has high sensitivity for detecting pleural thickening, subpleural consolidation, and ground-glass opacification equivalent in CT;3Soldati G Smargiassi A Inchingolo R et al.Is there a role for lung ultrasound during the COVID-19 pandemic?.J Ultrasound Med. 2020; (published online March 20.)DOI:10.1002/jum.15284Crossref Scopus (356) Google Scholar however, one pitfall is that there are occasions in which other imaging modalities are needed. For instance, lung ultrasound might not be able to detect a centrally located consolidation from bacterial superinfection. Furthermore, like many POCUS applications, lung ultrasound is often unable to discern the chronicity of a lesion, limiting its power of early COVID-19 diagnosis in the population with pre-existing pulmonary conditions. Patients with underlying asthma can have respiratory wheeze, which is not visible by lung ultrasound. Apart from using a stethoscope, the degree of airway obstruction in a mechanically ventilated patient could be assessed by various parameters, such as expiratory flow and waveform capnography. Proper documentation is one aspect POCUS users should be aware of. The POCUS images should be stored for later review for as long as possible. Smartphones or tablets provided by the institution—instead of personal ones—should be used to connect to the handheld POCUS device and for image storage. This practice will protect confidentiality and minimise the risk of the clinician's belongings being accidentally contaminated. For lung ultrasound, it is particularly important for the department to adopt a scanning protocol that every clinician agrees on, because there are different options available, including 8-zone, 12-zone, and 28-zone protocols, each applying different terminologies.4Volpicelli G Elbarbary M Blaivas M et al.International evidence-based recommendations for point-of-cares lung ultrasound.Intensive Care Med. 2012; 38: 577-591Crossref PubMed Scopus (2011) Google Scholar The operator should also annotate the cine loops accordingly otherwise it would be difficult for reviewers to determine the exact location being scanned. We embrace the extra precision and safety new technology brings but its limitations and optimisation must be understood to get the most benefits out of it without compromising standard of care. We declare no competing interests. COVID-19 outbreak: less stethoscope, more ultrasoundIn their Correspondence in The Lancet Respiratory Medicine, Jonathan Cheung and colleagues stressed the need to ensure staff safety in the airway management of patients with 2019 novel coronavirus disease (COVID-19).1 This safety should be guaranteed from the patient's first assessment. In fact, maintaining the safety of the doctor, who meets many people during his daily activity, avoids the spread of the disease to other patients and the possible creation of new epidemic outbreaks. However, patients with fever and respiratory symptoms do still need to be seen. Full-Text PDF