Evaluation of pulmonary B lines by different intensive care physicians using bedside ultrasonography: a reliability study

OBJECTIVE: To evaluate the agreement between intensive care physicians with similar training in the use of bedside lung ultrasonography in identifying pulmonary B lines, visualized in real time, to verify the reproducibility of the method. METHODS: A total of 67 patients with some ventilatory deterioration identified within 12 hours after a pulmonary ultrasonography in the period from November 2016 to March 2017 were analyzed, and all were admitted to an intensive care unit of a private hospital in Belo Horizonte, Minas Gerais. The lung ultrasonographies were performed by three different professionals, termed A, B and C, and the time interval between each lung ultrasonography was less than 3 hours. The only visualized chest zones were the anterior and lateral, defined as right and left anterior (1) zones (Z1R and Z1L, respectively), which were delimited by the clavicle, the sternum and the horizontal line perpendicular to the xiphoid process and anterior axillary line. The right and left lateral (2) zones (Z2R and Z2L, respectively) covered the lateral area between the anterior and posterior axillary lines, with the lower limit being the same horizontal line corresponding to the height of the xiphoid process. A lung zone was considered positive for B lines upon visualization of three or more of these lines, suggesting the presence of alveolar-interstitial syndrome. Using the Kappa value, we evaluated the agreement among the four zones according to the execution of each pair of professionals (AB, AC and BC). RESULTS: Approximately 80% of the areas that were visualized showed a moderate to substantial agreement, with the Kappa values ranging from 0.41 - 079 (p < 0.05; 95% CI). The highest levels of agreement occurred in the upper zones Z1R and Z1L between subgroups AC and BC, with a Kappa of approximately 0.65 (p < 0.001). In turn, Z2L showed one of the lowest agreements, with a Kappa of 0.36. CONCLUSION: The possible limitation of an examiner-dependent effect on lung ultrasounds was not found in this study, suggesting the good reproducibility of this diagnostic modality at the bedside.