Combatting COVID-19: is ultrasound an important piece in the diagnostic puzzle?

Abstract

The current COVID-19 pandemic is causing diagnostic and risk stratification difficulties in Emergency Departments (ED) worldwide. Molecular tests are not sufficiently sensitive, and results are usually not available in time for decision making in the ED. Chest x-ray (CXR) is a poor diagnostic test for COVID-19, and computed tomography (CT), while sensitive, is impractical as a diagnostic test for all patients. Lung ultrasound (LUS) has an established role in the evaluation of acute respiratory failure and has been used during the COVID-19 outbreak as a decision support tool. LUS shows characteristic changes in viral pneumonitis, and while these changes are not specific for COVID-19, it may be a useful adjunct during the diagnostic process. It is quick to perform and repeat and may be done at the bedside. The authors believe that LUS can help to mitigate uncertainty in undifferentiated patients with respiratory symptoms. This review aims to provide guidance regarding indications for LUS, describe the typical sonographic abnormalities seen in patients with COVID-19 and provide recommendations around the logistics of performing LUS on patients with COVID-19 and managing the infection control risk of the procedure. The risk of anchoring bias during a pandemic and the need to consider alternative pathologies are emphasised throughout this review. LUS may be a useful point-of-care test for emergency care providers during the current COVID-19 pandemic if used within a strict framework that governs education, quality assurance and proctored scanning protocols.

The role of PoCUS in the assessment of COVID-19 patients

“…Disinfection protocols include sheathing and disinfection of the ultrasound transducer [ 10 ]. Although an ultrasound device may act as a fomite for COVID-19, following a simple checklist can assist physicians in the disinfection process to safely reduce contamination (Table 1 ) [ 11 , 15 – 18 ].…”

“…Common pathologies visualized using LUS during COVID-19 are multifocal B lines, sub-pleural/lobar consolidations with decreased doppler signal, bilateral alveolar-interstitial pattern, pleural irregularities, air bronchograms and less commonly pleural effusions [ 9 , 11 , 18 , 30 – 33 ]. B-lines are defined as reverberation artifacts that are represented as smooth vertical lines that extend from the pleural line to the far field while obliterating A-lines [ 34 , 35 ].…”

“…Particularly in COVID-19, B-lines are commonly visualized in the posterior-lateral lung zones in the early phases of the disease [ 33 ]. In addition to pleuropathies, consolidations are pathological and can be identified peripherally and inferior to or disrupting the pleural line [ 9 , 18 , 30 , 31 ]. Air bronchograms are visualized as bright opacities distal to a consolidation when the ultrasound wave reflects off of an air-filled bronchus [ 9 , 18 , 31 ].…”

“…In addition to pleuropathies, consolidations are pathological and can be identified peripherally and inferior to or disrupting the pleural line [ 9 , 18 , 30 , 31 ]. Air bronchograms are visualized as bright opacities distal to a consolidation when the ultrasound wave reflects off of an air-filled bronchus [ 9 , 18 , 31 ]. As previously stated, pleural effusions are uncommon in COVID-19 but can be seen clearly as anechoic regions found cephalad to the diaphragm [ 9 , 18 , 30 , 31 ].…”

Robotic Ultrasound Scanning With Real-Time Image-Based Force Adjustment: Quick Response for Enabling Physical Distancing During the COVID-19 Pandemic

“…Ultrasound (US) image acquisition is a popular medical imaging method because it does not involve radiation (like x-ray or CT do), is generally regarded as safe, has a low cost compared to other medical imaging methods and is widely available. For a healthcare system that is struggling with COVID-19, US scanning is a way for COVID-19 diagnosis (Buda et al, 2020 ; McDermott et al, 2020 ), especially in developing countries where access to the lab kit is very limited. But there are some factors regarding the US scanning procedure during COVID-19 pandemic that need to be addressed.…”