PneumothoraxPTX

Where to put the probe

Window

Anterior chest, most superior point in a supine patient

Marker

Patient’s HEAD (12 o’clock)

probe

linear

preset

lung

depth

4–6 cm

Work the algorithm

1. Find the bat sign at the most anterior, most superior point on the side in question.
2. Look for sliding. If sliding is present at that spot, there is no pneumothorax there — move on.
3. No sliding? Check for a lung pulse and for any B-line; either one argues against pneumothorax.
4. Slide laterally to hunt the lung point — the transition from sliding to no sliding both confirms and sizes it.

What you are looking at

Pleural line without sliding

Still, bright line — watch several breaths before you commit. Suspicious, but not sufficient on its own.

A-lines

Persist in pneumothorax; their presence alongside absent sliding raises suspicion.

Lung point

The spot where sliding lung meets still pleura. Pathognomonic, and its position estimates the size — slide laterally to hunt it.

Barcode / stratosphere sign

M-mode with no sand layer — parallel lines all the way down. Side-by-side below.

Seashore vs barcode — the same question in M-mode

Top row: the pleural line in B-mode with the M-mode cursor (green) through it. Bottom row: the trace from that cursor — time runs left to right, depth top to bottom.

• Left — normal: Seashore signA smooth banded sky above the pleural line, then a grainy speckled beach below it. That grain is lung sliding written over time — apposed pleura moving against each other. No pneumothorax at this spot.
• Right — pneumothorax: Barcode / stratosphere signUninterrupted horizontal lines top to bottom: nothing beneath the pleural line changes over time, so there is no sand. Air in the pleural space has separated the layers.

Decision rules

Don’t be fooled — pitfalls

• Absent sliding has many causesPleurodesis, adhesions, mainstem intubation, apnea, severe bullae and dense consolidation all abolish sliding without any air in the pleural space.
• Subcutaneous emphysemaBlocks the beam entirely. Bright disorganized near field means the study is uninterpretable — say so rather than calling a pneumothorax.
• A bleb is not a pneumothoraxFocal absent sliding over emphysematous lung is common. The lung point is what settles it.
• Only scanning one spotA small anterior pneumothorax can hide two interspaces away. Document the zones you examined.

Bad image? Fix it

• Cannot see the pleura clearlyLinear probe, depth 4–6 cm, focus at the pleural line, gain moderate.
• Motion looks ambiguousUse M-mode: seashore versus barcode removes the guesswork, and freezes an image for the chart.
• Ventilated patient, chest moves under the probeRest the heel of your hand on the chest so the probe travels with the wall rather than across it.
• Need to check the apex in a collared trauma patientCome in from the side above the clavicle with a small footprint and accept a partial view; document the limitation.

So what — what the finding changes

• No sliding + hypotension + distended neck veinsTreat as tension physiology and decompress — do not wait for a chest film.
• Suspected pneumothorax, stable patientConfirm with imaging per local practice, size it, and decide observation versus drainage with the team.
• Post-procedure check (line, biopsy, thoracentesis)Scan the same anterior point before and after; a change from sliding to still is your answer.

Related views

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