Standardized Lung Ultrasound Assessment Protocol

We used reliable techniques based on the international evidence-based recommendations for point-of-care lung ultrasound [19 (link)] that recommended using a complete eight-zone lung ultrasound examination to evaluate the LUSS [12 (link)]. The anterior and lateral chest wall were divided into eight areas. Areas 1 and 2 denote the upper anterior and lower anterior chest areas, respectively, and areas 3 and 4 denote the upper lateral and basal lateral chest areas, respectively. For clinical practicability, we adopted the eight-zone examination in the study. Each zone was scored according to the lung ultrasound pattern as follows [10 (link)–12 (link)] (Fig. 1): the presence of lung sliding with A-lines or fewer than two isolated B-lines, scored 0; when multiple well-defined B-lines (B1-lines) presented, scored 1; the presence of multiple coalescent B-lines (B2-lines), scored 2; and when presented with a tissue pattern characterized by dynamic air bronchograms (lung consolidation), scored 3. The worst ultrasound pattern observed in each zone was recorded and used to calculate the sum of the scores (total score = 24).Fig. 1

Eight-zone lung ultrasound examination protocol and lung ultrasound pattern. A: Each hemithorax is separated into four quadrants: anterior and lateral zones (separated by the anterior axillary lines) with each one divided into upper and lower portions. AAL indicates the anterior axillary line. B: Lung ultrasound pattern. (a): A pattern; (b): B1 pattern; (c): B2 pattern; (d): C pattern (lung consolidation).