Wondering about A lines?

Thoracic US is one of the most useful point of care modalities available in the critical care setting. It is well recognised that bedside US outperforms clinical examination and plain radiography in the evaluation of certain pathologies in the hands of an experienced operator

The ultrasound beam is completely reflected by air present in the lungs. Interpretation of lung US relies on the presence of artefacts which correlate with pathologic processes

A lines are

  • horizontal hyperechoic (bright) lines seen below the pleural interface
  • caused by reverberation artefact or reflection of the US wave between the pleural line and the probe
  • each A line is separated by a distance that is the thickness of subcutaneous tissue between the probe and the pleural surface
  • best seen when the probe is perpendicular to the curved lung surface (not the skin surface)

A normally aerated lung shows A lines and lung sliding – this pattern rules out other pathological US signs

A lines can occur in other areas of the body eg. reverberation artefacts are described in the bowel wall and blood vessel walls

How many A lines are present in this clip?

Read more about lung PoCUS, join the revolution!



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