Bedside lung ultrasound: the points every protocol shares

Lung sliding, B-lines, consolidation, and lung point — the common grammar behind the different thoracic POCUS protocols.

There are several published protocols for bedside lung ultrasound — with different numbers of thoracic windows and different acronyms. Despite the variations, they all share the same basic visual grammar: pleural line, lung sliding, A-lines, B-lines, and consolidation.

Lung sliding as the first sign to look for

The sliding of the pleural line during the respiratory cycle is the most reproducible finding among beginner examiners. Its absence is highly sensitive for pneumothorax, but not specific — it can also occur with mainstem intubation, apnea, or pleural adhesions.

B-lines and the clinical context

Diffuse, bilateral B-lines in a patient with acute dyspnea suggest interstitial syndrome — most often cardiogenic pulmonary edema in the right context. Focal, unilateral B-lines completely change the list of hypotheses, pointing toward pneumonia or pulmonary contusion.

The value of lung ultrasound isn't replacing clinical reasoning — it's bringing forward information that used to arrive only after a chest X-ray or CT scan, often minutes or hours after the therapeutic decision had already been made.