UMEM Educational Pearls

Category: Critical Care

Title: Lung Ultrasound in Pulmonary Edema

Keywords: lung ultrasound, pulmonary edema, B-lines (PubMed Search)

Posted: 3/11/2014 by Feras Khan, MD
Click here to contact Feras Khan, MD

“B-Lines” can be seen in patients with pulmonary edema (see attached image below)
A “B-line” is a reverberation artifact defined by Lichtenstein as having several properties:

1. A comet-tail artifact

2. Arising from the pleural line

3. Well defined

4. Hyperechoic

5. Long (does not fade)

6. Erases A lines

7. Moves with lung sliding

A large amount of B-lines is pathologic
These artifacts are also called “comet-tails” due to their appearance
One or two B-lines can be seen in dependent lung zones in normal lungs
AIS (Alveolar interstitial syndrome) describes a group of conditions including pulmonary edema, interstitial pneumonia, and pulmonary fibrosis that show similar findings on lung ultrasonography
The most common presentation of this syndrome is from cardiogenic pulmonary edema and is characterized by B-lines in multiple lung zones
B lines correspond with interlobular septal thickening on CT scans, which represent pulmonary vascular congestion

Technique

B-mode is used with the micro-convex (cardiac) probe scanning in at least 8 lung zones
Quantify the number of B-lines in each zone
A lung zone is considered to be “positive” when three or more B-lines are present in a longitudinal plane between two ribs
Two or more regions bilaterally are required to be defined as AIS
Bilateral diffuse B-lines have a specificity of 95% and a sensitivity of 97% for the diagnosis of pulmonary edema

References

1. Lichtenstein D, Mezie re G, Biderman P, et al. The comet-tail artifact. An ultra- sound sign of alveolar-interstitial syndrome. Am J Respir Crit Care Med 1997; 156(5):1640–6.

Attachments

1403111625_Fig6.1BLINESFINAL.jpg (55 Kb)