The BLUE-points: three standardized points used in the BLUE-protocol for ultrasound assessment of the lung in acute respiratory failure
© Springer-Verlag 2011
Received: 29 July 2010
Accepted: 18 February 2011
Published: 30 March 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 .
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):2277–2284PubMedView ArticleGoogle Scholar
- Lichtenstein D, Mezière G (2008) Relevance of lung ultrasound in the diagnosis of acute respiratory failure. The BLUE-protocol. Chest 134:117–125PubMedPubMed CentralView ArticleGoogle Scholar
- Lichtenstein D, Holzapfel L, Frija J (2000) Projection cutanée des pneumothorax et impact sur leur diagnostic échographique. Réan Urg 9(Suppl 2):138sGoogle Scholar
- Guyton CA, Hall JE (1996) Textbook of medical physiology, 9th edn. W.B. Saunders, Philadelphia, pp 496–497Google Scholar
- 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 25:955–958PubMedView ArticleGoogle Scholar
- Lichtenstein D, Lascols N, Mezière G, Gepner A (2004) Ultrasound diagnosis of alveolar consolidation in the critically ill. Intensive Care Med 30:276–281PubMedView ArticleGoogle Scholar
- Lichtenstein D, Mezière G, Biderman P, Gepner A (2000) The lung point: an ultrasound sign specific to pneumothorax. Intensive Care Med 26:1434–1440PubMedView ArticleGoogle Scholar
- van der Werf TS, Zijlstra JG (2004) Ultrasound of the lung: just imagine. Intensive Care Med 30:183–184PubMedView ArticleGoogle Scholar