Summary of Coronavirus COVID-19 examination and follow-up
In comparison between non-COVID-19 pneumonia and COVID-19 pneumonia, COVID-19 pneumonia is more likely to have a peripheral distribution [84] (Figure 23). In addition to HR-CT scan and X-ray of the lung, ultrasound can also be used for the diagnosis and follow-up of the disease [85]. By using a curved transducer (5–1 MHz), the morphology and changes of subpleural lesions are clearly displayed. Due to the option to use even the low-frequency of the transducer, changes of air and water contents in consolidated peri-pulmonary tissues and an air bronchogram sign can be depicted (Figure 24).
The blood supply and lesion progression in peripulmonary consolidation can be monitored by using the color or power Doppler technique [86]. Currently, ultrasound of the lung is limited in the diagnosis and treatment of central lung diseases due to the attenuation of sound waves by normal lung and bone tissues. The diagnosis of lung pathologies relies on the artifacts of peri-pulmonary lesions [87–88]. The artifacts exist because of an abnormal ratio of air and water contents in alveoli and interstitial tissues. In order to improve the diagnostic ultrasound lung tool, the use of an abdominal curved array probe (5–1 MHz) seems to be helpful. Typical for the COVID-19 disease are the thickening of the pleural line with pleural line irregularity. The pleural line could be unsmooth, discontinuous and interrupted [85, 89] (Figures 25–26).
The appearance of B-lines artifacts could vary from focal, to multifocal and confluent pattern. The consolidations could vary in different patterns, including multifocal small subpleural consolidations up to non-translobar and translobar with occasional air bronchograms [5]. Pleural effusions are uncommon in coronavirus COVID-19 disease.
An indirect sign for recovering is the appearance of A-lines during the recovery phase [85] (Figure 27).
In summary, in our experience, we consider that lung ultrasound will have a major utility for the management of COVID-19 pneumonia in the ICU due to its safety, repeatability, low cost and point of care use. HR-CT may be reserved in the follow-up if lung ultrasound is not able to answer the clinical question. In our personal experience lung ultrasound could be used for rapid assessment of the severity of SARS-CoV-2 pneumonia, to track the evolution of disease during follow-up and to monitor lung recruitment maneuvers. Additional ultrasound can track the response to prone position and the management of extracorporeal membrane therapy [85]. With increased use of bedside ultrasound in the ICU, patients can be protected from unnecessary radiation and therapy delays. The transport of high-risk patients to X-ray examinations can be avoided.
