The BLUE-points: three standardized points used in the BLUE-protocol for ultrasound assessment of the lung in acute respiratory failure

Sir,The BLUE-protocol is designed for immediate diagnosis ofacute respiratory failure, one of the most distressing set-tings for patients 1. Physicians would appreciate stan-dardized areas of investigation. The BLUE-points respondto this quest. Of the seven principles of lung ultrasound 2,principle 2, indicating that the disorders are distributedalong an Earth–Sky axis, and principle 3, which recalls thatthe lung is the most voluminous organ, are used.Bedside use and absence of irradiation favor the use ofultrasound 3. Studies have shown that most acute lungdisorders benefit from standardized locations. Clinicallyrelevant interstitial syndrome locates anteriorly 4. Freepneumothoraces always locate anteriorly 5. As free fluidsfollow gravity rules 6, all cases of free pleural fluideffusion, regardless its abundance locate at least posteriorlyabove the diaphragm 7. Lung consolidation can locateeverywhere depending on the cause and extension, yieldingsensitivity lower than other disorders, 90% 8, yet itsposterior location above the diaphragm in critically illpatients with pneumonia is usual 4.We consider the hands of the patient (called BLUE-hands, roughly standard doctor’s hands size in standardadults; physicians with large or small hands would makethe adaptation once for all). The hands, applied as shown inFig. 1, define the anterior chest wall. This is of great helpin patients with major obesity, nipple ptosis, etc. Thisworks with patients of any size, neonate included. TheBLUE-hands allows to define five regions of interest. Theupper and lower BLUE-points, the phrenic line, defined inFig. 1, are anterior. The phrenic point is lateral, defined inFig. 2. The PLAPS-point, defined in Fig. 2 from the lowerBLUE-point, is posterior. The Carmen maneuver extendsthe location of the BLUE-points: by a slight back-and-forthmovement of the probe held longitudinally to the left andthe right, remaining at the same skin point and gently