BLUE Point Locations for Thoracic Ultrasound
The first (upper) BLUE point is located at the anterior chest wall in the mid-clavicular line at the 2nd-3rd intercostal space, and the second (lower) BLUE point is located at the anterior chest wall in the mid-clavicular line at the 4th-5th intercostal space.
Anatomical Positioning
The BLUE protocol (Bedside Lung Ultrasound in Emergency) uses standardized scanning points on the anterior chest wall for rapid assessment of respiratory failure 1, 2:
First BLUE Point (Upper)
- Location: Mid-clavicular line, 2nd-3rd intercostal space
- Anatomical landmark: Upper anterior chest area
- Purpose: Evaluates the upper anterior lung fields bilaterally
Second BLUE Point (Lower)
- Location: Mid-clavicular line, 4th-5th intercostal space
- Anatomical landmark: Lower anterior chest area
- Purpose: Evaluates the lower anterior lung fields bilaterally
Clinical Context
These points are part of a systematic anterior chest examination protocol used primarily in emergency and critical care settings 2. The BLUE protocol specifically focuses on anterior chest wall scanning because:
- Patients are typically supine in emergency situations
- Anterior scanning is rapid and accessible
- Most pathology causing acute respiratory failure can be detected from anterior views
- The technique evaluates for lung sliding, A-lines, B-lines, consolidation, and pleural effusion 1, 2
Scanning Technique
At each BLUE point, the probe should be:
- Oriented with the marker directed cranially (toward the head)
- Placed in the intercostal space parallel to the ribs to minimize rib shadowing
- Used to assess for pleural sliding, A-lines, B-lines, and consolidation patterns 1
Important caveat: While the BLUE protocol uses these two anterior points per hemithorax for rapid assessment, a complete thoracic ultrasound examination typically includes additional lateral and posterior scanning zones for comprehensive evaluation 3, 4. The BLUE points represent a focused, time-sensitive approach specifically designed for emergency respiratory failure assessment.