ABSENT PLEURAL SLIDING 

Absent pleural sliding causes a lack of shimmer at the pleural line. 

The M mode differentiates air in the pleural space from lung. Air causes a barcode sign. Lung causes a lung pulse. 

Differentiate the causes of absent pleural sliding by considering the clinical presentation, the location, the characteristics of the pleura and the underlying lung and m mode features. Below is how to differentiate the common causes of absent pleural sliding. 

THIN PLEURAL LINE

THICK PLEURAL LINE

+ lung pulse (+/- B lines/comet tails)

 adhesions

consolidation

bullous in diseased lung

unventilated diseased lung

pleural disease eg mesothelioma, pleuradhesis