The bedside lung ultrasonography in emergency (BLUE) points used in the BLUE protocol with the patient in the supine or semirecumbent position: (left) upper BLUE points and lower BLUE points; (right) posterolateral alveolar and/or pleural syndrome (PLAPS) point. Two hands (of the size of the patient’s hands, thus allowing universal use in all kinds of patients) applied this way usually cover the anterior lung surface (note the upper finger applied just below the clavicle). The upper BLUE point is defined using the middle of the upper hand. The lower BLUE point is defined using the middle of the lower palm. This makes a symmetrical, trapezoid definition that follows the lung anatomy, is usually far from the heart and the abdominal structures, and keeps clinical value. The lateral continuation of the lower BLUE point, as posterior as possible behind the posterior axillary line, defines the PLAPS point, always located quite a bit above the diaphragm.
Modified with permission from Lichtenstein and Mezière (10).