The Pre-brief
The phrase “bat view” was coined by Professor Daniel Lichtenstein, an intensivist from Paris who defined much of what we perform as lung ultrasound in the acutely unwell today.
What is a “Bat View”?
“The pattern created by the upper rib (left wing), pleural line (belly) and lower rib (right wing) has been labelled the bat sign”
Above shows an example of a lung ultrasound with the “bat” overlaid.
Now, seeing that the accurate identification of the pleural line is the foundation of all lung ultrasound imaging, it automatically follows that a perfect view of the “bat” is essential to accurate lung imaging.
So how do we get perfect bat views?
Many of us when performing anterior lung imaging place our probes in a vertical orientation, starting from the midclavicular line and working laterally, like below:
Notice something?
The probe is placed vertically, however, the ribs run at an angle.
You’re getting a skewed view of “the bat” and thus an imperfect view of the pleural line.
What is required is a slight rotation of the probe, so that it lies at the same angle that the ribs run:
To know if you’ve got it right, rotate your probe, then move up and down in between rib spaces.
You know you’ve got it right because the rib spaces you see on your “Bat view” will be equal apart in distance.
The next thing to do is to make sure you’re as perpendicular to the pleural line as you can be- this is accomplished by tilting your probe, until you generate the brightest pleural line with as many A-lines underneath it as possible.
This can be really important:
- when looking for a pneumothorax – absent lung sliding and a lung point are easier to see
- when assessing for lung water – B lines are defined by their ability to eliminate A lines; you’ll want to see them make sure you’re actually looking at B lines, and not Z lines (a similar reverberation artifact that doesn’t travel all the way down the screen!)
Above is an imperfect image. You can’t see the A lines very well, the Bat isn’t centered in the screen, and as a result, it would be easy to mistake the top left of the screen as a potential area of consolidation.
This is an excellent example of a “Bat” view. The rib space is centered, the pleural line is very bright, and 2 A lines are visible – suggesting that the probe is perfectly positioned perpendicular to the pleural space.
Accurate diagnosis requires accurate imaging – so get out there and work on those Bat views!
Many thanks to my wonderful friend Dr Kylie Baker, for inspiring this post and making a superb video that improved my lung sonography immeasurably (linked below).
The Debrief
- The “Bat” view describes the view obtained of the pleural line, bounded on either side by two ribs. It is the “home screen” of lung ultrasound in the anterior zones
- An optimal view of the pleural line allows for optimal visualization of all of the described artifacts- lung sliding, B lines, pleural abnormalities, and lung points
- Because ribs are angulated, getting perfect “bat” views requires probe angulation to align yourself with the rib space
References
- Lichtenstein D. Lung Ultrasound in the Critically Ill. Springer International Publishing (2015); DOI: 10.1007/978-3-319-15371-1
- BLUE team. Getting good bat views. https://youtu.be/KzYYPrOdZc8
- Australian Institute of Ultrasound in medicine. Kylie Baker demonstrating Lung Ultrasound. https://youtu.be/N8SDbpQXDpw
