- Brief Communication
- Open Access
The BLUE-points: three standardized points used in the BLUE-protocol for ultrasound assessment of the lung in acute respiratory failure
Critical Ultrasound Journal volume 3, pages 109–110 (2011)
The BLUE-protocol is designed for immediate diagnosis of acute respiratory failure, one of the most distressing settings for patients . Physicians would appreciate standardized areas of investigation. The BLUE-points respond to this quest. Of the seven principles of lung ultrasound , principle 2, indicating that the disorders are distributed along an Earth–Sky axis, and principle 3, which recalls that the lung is the most voluminous organ, are used.
Bedside use and absence of irradiation favor the use of ultrasound . Studies have shown that most acute lung disorders benefit from standardized locations. Clinically relevant interstitial syndrome locates anteriorly . Free pneumothoraces always locate anteriorly . As free fluids follow gravity rules , all cases of free pleural fluid effusion, regardless its abundance locate at least posteriorly above the diaphragm . Lung consolidation can locate everywhere depending on the cause and extension, yielding sensitivity lower than other disorders, 90% , yet its posterior location above the diaphragm in critically ill patients with pneumonia is usual .
We consider the hands of the patient (called BLUE-hands, roughly standard doctor’s hands size in standard adults; physicians with large or small hands would make the adaptation once for all). The hands, applied as shown in Fig. 1, define the anterior chest wall. This is of great help in patients with major obesity, nipple ptosis, etc. This works with patients of any size, neonate included. The BLUE-hands allows to define five regions of interest. The upper and lower BLUE-points, the phrenic line, defined in Fig. 1, are anterior. The phrenic point is lateral, defined in Fig. 2. The PLAPS-point, defined in Fig. 2 from the lower BLUE-point, is posterior. The Carmen maneuver extends the location of the BLUE-points: by a slight back-and-forth movement of the probe held longitudinally to the left and the right, remaining at the same skin point and gently gliding over the underskin, one immediately scans 1 cm from either part of the BLUE-point, improving detection of B-lines or C-lines.
The upper BLUE-point immediately informs on pneumothorax (A′-profile) in semirecumbent (i.e., Stage 1′, usually performed in dyspneic, nonventilated) patients. The lower BLUE-point immediately informs on pneumothorax in supine (i.e., stage 1, performed on mechanical ventilation) patients. The upper and lower BLUE-points immediately inform on pulmonary edema (B-profile) or immediately suggest pulmonary embolism (A-profile). The PLAPS-point allows immediate diagnosis of pneumonia, when combined with negative anterior findings among others . Note that the BLUE-points are not appropriate for subtle approach of ARDS, nor for comprehensive search of small anterior (C-profile) or lateral consolidations, requiring more liberal scanning. The lung point, as opposed to the BLUE-points, is located according to the pneumothorax extent .
In the BLUE-protocol, we advise a 5-MHz microconvex probe resulting in a small footprint, and a good resolution for both superficial and deep disorders (Fig. 2). This probe also allows satisfactory analysis of the vessels, heart, optic nerves, belly, i.e., whole body analysis, neonate excepted . Those who do not benefit from this probe will need the good resolution of abdominal probes for the anterior analysis of the artifacts, the good superficial resolution of linear probes for details on lung sliding, and the good ergonomy of cardiac probes for PLAPS detection, taking maximal care for disinfecting each probe between changes, which prevents the BLUE-protocol to be performed within 3 min as advocated .
Standardizing the BLUE-points should favor widespread use of the BLUE-protocol, enabling this visual medicine to be applied to most patients .
Irwin RS, Rippe JM (2008) Intensive care medicine, 6th edn. Lippincott Williams and Wilkins, Philadelphia, pp 491–496
Lichtenstein D (2010) Introduction to lung ultrasound. In: Lichtenstein D (ed) Whole body ultrasonography in the critically ill. Heidelberg, Springer, pp 117–127
Brenner DJ, Hall EJ (2007) Computed tomography—an increasing source of radiation exposure. New Engl J Med 357(22):2277–2284
Lichtenstein D, Mezière G (2008) Relevance of lung ultrasound in the diagnosis of acute respiratory failure. The BLUE-protocol. Chest 134:117–125
Lichtenstein D, Holzapfel L, Frija J (2000) Projection cutanée des pneumothorax et impact sur leur diagnostic échographique. Réan Urg 9(Suppl 2):138s
Guyton CA, Hall JE (1996) Textbook of medical physiology, 9th edn. W.B. Saunders, Philadelphia, pp 496–497
Lichtenstein D, Hulot JS, Rabiller A, Tostivint I, Mezière G (1999) Feasibility and safety of ultrasound-aided thoracentesis in mechanically ventilated patients. Intensive Care Med 25:955–958
Lichtenstein D, Lascols N, Mezière G, Gepner A (2004) Ultrasound diagnosis of alveolar consolidation in the critically ill. Intensive Care Med 30:276–281
Lichtenstein D, Mezière G, Biderman P, Gepner A (2000) The lung point: an ultrasound sign specific to pneumothorax. Intensive Care Med 26:1434–1440
van der Werf TS, Zijlstra JG (2004) Ultrasound of the lung: just imagine. Intensive Care Med 30:183–184
Rights and permissions
Open Access This article is distributed under the terms of the Creative Commons Attribution 2.0 International License ( https://creativecommons.org/licenses/by/2.0 ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
About this article
Cite this article
Lichtenstein, D.A., Mezière, G.A. The BLUE-points: three standardized points used in the BLUE-protocol for ultrasound assessment of the lung in acute respiratory failure. Crit Ultrasound J 3, 109–110 (2011). https://doi.org/10.1007/s13089-011-0066-3
- Acute Respiratory Failure
- Pleural Fluid
- Anterior Chest Wall
- Lung Ultrasound