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Lung POCUS in the FOCUS Protocol and its Diagnostic Patterns

Writer: MaytaMayta

POCUS Lung Scanning Locations

  1. Upper Anterior Chest:

    • Assess for pneumothorax, upper lobe pathology, and lung sliding.

  2. Lower Anterior Chest:

    • Detect pleural effusion, pulmonary edema, and consolidations in mid to lower lobes.

  3. Upper Lateral Chest:

    • Evaluate pleural effusion, consolidations, or interstitial syndromes.

  4. Lower Posterolateral Chest:

    • Primary location for detecting pleural effusion, atelectasis, or basal consolidations.


 

Ultrasound Signs in Lung POCUS

Sign

Appearance

Mechanism/Interpretation

A-lines

Horizontal, repetitive, echogenic lines parallel to pleura

Caused by normal air-filled alveoli reflecting sound waves; seen in normal lung or pneumothorax (with no lung sliding).

B-lines

Vertical, bright artifacts extending from pleura to screen edge

Reverberation artifact from water-filled interstitial space; seen in pulmonary edema, ARDS, or pneumonia.

C-lines

Localized, fragmented hyperechoic artifacts

Shred-like sign from small consolidated areas; specific for pneumonia or subpleural consolidations.

Seashore Sign

Normal sandy appearance in M-mode; static chest wall with sliding lung

Indicates normal lung aeration and sliding; excludes pneumothorax.

Barcode/Stratosphere

Alternating static lines (M-mode)

Indicates pneumothorax; absence of sliding lung.

Shred Sign

Jagged, hypoechoic areas with ill-defined borders

Indicates consolidation; typically seen in bacterial pneumonia.

Hepatization

Lung tissue appearing liver-like (solid with hyperechoic air bronchograms)

Found in lobar pneumonia or severe consolidation.

Curtain Sign

Normal hyperechoic lung edge moving over hypoechoic structures below

Indicates normal diaphragmatic and lung function.

Fibrin Strands

Echogenic linear fibrin in pleural effusion

Suggestive of empyema or long-standing effusion in pleural space.

Disease Patterns and Key Ultrasound Findings





How to Interpret Findings in Context

  1. Acute Pulmonary Edema:

    • Diffuse B-lines, bilateral.

    • Sliding present.

    • Key mnemonic: "Wet lungs bilaterally."

  2. Acute Respiratory Distress Syndrome (ARDS):

    • Patchy B-lines, bilateral.

    • Thickened pleura.

    • Effusions may be present.

    • Key mnemonic: "Patchy lungs, irregular pleura."

  3. Bacterial Pneumonia:

    • Shred sign, consolidation with air bronchograms.

    • Focal B-lines around consolidation.

    • Key mnemonic: "Shredded consolidation focal."

  4. Pneumothorax:

    • Absent sliding, barcode sign on M-mode.

    • Key mnemonic: "Silent lung with a barcode."

  5. COPD/Asthma:

    • A-lines with sliding.

    • Key mnemonic: "Normal A-lines, clear pleura."


 

Tips to Remember

  • "A-lines Air": Normal or over-aerated lungs like in COPD or pneumothorax.

  • "B-lines Bad": Fluid accumulation in interstitial space or alveoli (edema, ARDS).

  • "Shred or Hepatized?": Think pneumonia or atelectasis.

  • Curtain = Clear: Normal diaphragm movement obscuring deeper structures.

  • Barcode = Bad Lung Sliding: Pneumothorax diagnosis.

Using this systematic approach with memorization aids will help you efficiently diagnose lung conditions during POCUS assessments. Let me know if you'd like to dive deeper into any specific disease or concept!

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Post: Blog2_Post

Message for International Readers
Understanding My Medical Context in Thailand

By Uniqcret, M.D.
 

Dear readers,
 

My name is Uniqcret, which is my pen name used in all my medical writings. I am a Doctor of Medicine trained and currently practicing in Thailand, a developing country in Southeast Asia.
 

The medical training environment in Thailand is vastly different from that of Western countries. Our education system heavily emphasizes rote memorization—those who excel are often seen as "walking encyclopedias." Unfortunately, those who question, critically analyze, or solve problems efficiently may sometimes be overlooked, despite having exceptional clinical thinking skills.
 

One key difference is in patient access. In Thailand, patients can walk directly into tertiary care centers without going through a referral system or primary care gatekeeping. This creates an intense clinical workload for doctors and trainees alike. From the age of 20, I was already seeing real patients, performing procedures, and assisting in operations—not in simulations, but in live clinical situations. Long work hours, sometimes exceeding 48 hours without sleep, are considered normal for young doctors here.
 

Many of the insights I share are based on first-hand experiences, feedback from attending physicians, and real clinical practice. In our culture, teaching often involves intense feedback—what we call "โดนซอย" (being sliced). While this may seem harsh, it pushes us to grow stronger, think faster, and become more capable under pressure. You could say our motto is “no pain, no gain.”
 

Please be aware that while my articles may contain clinically accurate insights, they are not always suitable as direct references for academic papers, as some content is generated through AI support based on my knowledge and clinical exposure. If you wish to use the content for academic or clinical reference, I strongly recommend cross-verifying it with high-quality sources or databases. You may even copy sections of my articles into AI tools or search engines to find original sources for further reading.
 

I believe that my knowledge—built from real clinical experience in a high-intensity, under-resourced healthcare system—can offer valuable perspectives that are hard to find in textbooks. Whether you're a student, clinician, or educator, I hope my content adds insight and value to your journey.
 

With respect and solidarity,

Uniqcret, M.D.

Physician | Educator | Writer
Thailand

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