The use of lung ultrasound in COVID-19

Geographical distribution of publications on use of lung ultrasound in coronavirus disease 2019 (COVID-19) based on the results of the literature review. a) Distribution of the publications according to the six World Health Organization regional offices for a total of 200 publications on use of lung ultrasound in COVID-19, including 187 national articles and 13 multinational papers. Data presented as “EURO” comprise papers published by one single country in Europe as well as six articles jointly published by more than one European country. The literature review identified seven inter-regional articles (i.e. papers jointly published by authors from countries in different parts of the world) which were not included in any specific region and are therefore presented separately in this figure. b) The 31 countries involved in the literature review are listed together with the number of national articles submitted by each country. The numbers provided between brackets indicate, when appropriate, the number of multinational studies to which a given country has contributed. More detailed information about the reviewed publications is provided in supplementary material S1.

Specific field of application of lung ultrasound in the different studies. COVID-19: coronavirus disease 2019. ^#: including evaluation of the diagnostic accuracy of lung ultrasound in comparison with lung computed tomography and chest radiography; ^¶: screening, contrast-enhanced ultrasound, application of lung ultrasound in nursing homes, “self-ultrasound”, guiding therapy, deciding on intubation, wireless ultrasound, assisting in patient resuscitation, application of lung ultrasound with artificial intelligence and with robotics.

Standardised lung ultrasound examination. a) Anatomical landmarks, topographic regions and b) example of lung ultrasound report form. Each hemithorax is divided into anterior, lateral and posterior regions, according to anatomical landmarks (anterior and posterior axillary lines and internipple line), as follows. R1: right anterior superior; R2: right anterior inferior; R3: right lateral superior; R4: right lateral inferior; R5: right posterior superior; R6: right posterior inferior; L1: left anterior superior; L2: left anterior inferior; L3: left lateral superior; L4: left lateral inferior; L5: left posterior superior; L6: left posterior inferior. The presence or absence of lung sliding and pleural effusion for each region should be noted. A lung ultrasound score ranging from 0 to 3 is assigned according to the degree of aeration loss and the presence of any other pathological sign (extension of findings), allowing calculation of lung ultrasound score for left and right lung and total score. In addition, the lung ultrasound report form may include information about examination quality, mechanical ventilation settings and arterial blood gas results. LUS: lung ultrasound.