Lung Ultrasound Morse Code Sign

Decoding Lung Ultrasound: The Morse Code to Spotting Hidden Lung Issues

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Beau Callahan in Health & Wellness December 2025 • 4 min read.

"Can a simple lung ultrasound reveal more than traditional methods in patients with breathing difficulties?"


When a 60-year-old man with severe COPD and extreme dyspnea arrived at the intensive care unit (ICU), doctors faced a challenge. Traditional methods like chest X-rays sometimes fall short in providing a clear picture of the underlying issues. In this case, lung auscultation revealed prolonged expiration and decreased vesicular breath sounds, prompting further investigation.

A standard chest X-ray showed prominent hilar vascular shadows, but no parenchymal consolidation, leaving the medical team searching for more definitive answers. This is where lung ultrasound stepped in, offering a quick, non-invasive way to assess the patient's condition right at the ICU bedside.

To fully understand the patient's COPD and identify any additional complications, a high-resolution CT scan was performed. This scan revealed a giant subpleural bullae, a large air-filled space near the surface of the lung. While ultrasound can't directly visualize these bullae, it can detect subtle signs that indicate their presence and help rule out other dangerous conditions.

Unlocking the 'Morse Code Sign': How Ultrasound Sees the Unseen

Lung Ultrasound Morse Code Sign

Typically, ultrasound struggles to directly image bullae. However, this case demonstrated a fascinating phenomenon: even with giant bullae, lung sliding can still be observed, albeit in a minimal form. This is particularly valuable when pneumothorax (collapsed lung) is suspected based on radiography. Detecting even trace lung sliding allows doctors to confidently rule out pneumothorax.

In conditions like COPD and asthma, minimal lung sliding can occur. While B-lines (indicators of fluid in the lungs) would typically be helpful, they are often absent in bullous disease due to the destruction of interlobular septa. However, focusing on the pleural line (the membrane surrounding the lungs) can reveal characteristic, regular perturbations that stop exactly at the pleural line without spreading above it.

  • What is "Morse code sign" in lung ultrasound? It describes tiny movements at the pleural line that resemble Morse code.
  • How does "Morse code sign" appear? It appears as tiny perturbations that stop exactly at the pleural line without spreading above it.
  • What does "Morse code sign" signify? This sign indicates a variant of extremely discreet lung sliding that allows one to rule out the diagnosis of pneumothorax in those patients with giant bulla.
These subtle movements at the pleural line resemble the dots and dashes of Morse code, hence the suggested term "Morse code sign." This sign represents a variant of extremely discreet lung sliding, providing critical information for diagnosis and treatment decisions.

The Future of Lung Ultrasound: A Clearer Picture for Complex Cases

This case highlights the power of lung ultrasound as a valuable tool in assessing patients with COPD, dyspnea, and giant bullae. By recognizing subtle signs like the "Morse code sign," clinicians can gain critical insights that might be missed by traditional imaging techniques.

Lung ultrasound offers a non-invasive, readily available method for evaluating lung conditions at the bedside. Its ability to detect even minimal lung sliding can be crucial in ruling out pneumothorax and guiding treatment decisions, especially in complex cases involving bullous disease.

As ultrasound technology continues to advance and clinicians become more proficient in its use, we can expect even greater applications for lung ultrasound in the diagnosis and management of respiratory conditions, leading to improved patient outcomes and more informed clinical decision-making.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1007/s00134-018-5317-3, Alternate LINK

Title: Lung Ultrasound In A Dyspneic Patient With Giant Bullae

Subject: Critical Care and Intensive Care Medicine

Journal: Intensive Care Medicine

Publisher: Springer Science and Business Media LLC

Authors: Daniel Lichtenstein, Gemma Rialp

Published: 2018-07-20

Everything You Need To Know

1

What exactly is the "Morse code sign" in the context of lung ultrasound?

The "Morse code sign" is a specific observation made during lung ultrasound. It refers to tiny, regular perturbations or movements seen at the pleural line, the membrane surrounding the lungs. These movements are analogous to the dots and dashes of Morse code.

2

How does the "Morse code sign" actually appear on a lung ultrasound?

The "Morse code sign" manifests as subtle, periodic undulations at the pleural line. These perturbations are unique in that they do not extend beyond the pleural line. This characteristic distinguishes it from other lung ultrasound findings and helps in the diagnostic process.

3

Why is the "Morse code sign" important for medical professionals to recognize?

The presence of the "Morse code sign" is significant because it indicates a form of minimal lung sliding. This is particularly useful in patients with conditions like COPD and giant bullae, where standard imaging may be inconclusive. Detecting this sign helps to rule out pneumothorax, a dangerous condition where the lung collapses, by confirming that the lung is still partially sliding against the chest wall.

4

What advantages does lung ultrasound offer in assessing lung conditions, especially when compared to traditional methods?

Lung ultrasound offers a non-invasive method to evaluate lung conditions, especially in critical care settings. Its use in patients with conditions like COPD allows for rapid assessment at the bedside. The detection of the "Morse code sign" helps to differentiate between conditions, guiding treatment decisions, and avoiding unnecessary procedures.

5

How does identifying the "Morse code sign" directly influence patient care in a case of suspected lung issues?

In the context of this information, the "Morse code sign" is critical because traditional methods may fall short. For instance, in a 60-year-old man with severe COPD, the 'Morse code sign' could confirm that the patient does not have a pneumothorax. This allows doctors to focus on the management of COPD and avoid interventions that could be harmful if a pneumothorax were incorrectly diagnosed.

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