A 15 year old male presents with acute onset, 5/10, sub-sternal chest pain that started at rest just prior to presentation. He has a history of pneumothorax treated with oxygen overnight 3-4 months prior. Breath sounds are auscultated bilaterally and vital signs are stable.
The ultrasound is immediately wheeled into the room and you obtain the following images and clips below:
You observe “barcode” sign on the left and in the video clip there is no lung sliding. The lung point is not visualized on ultrasound. The diagnosis of left-sided pneumothorax is made within minutes of his arrival and he is started on O2 via NRB. He later goes for chest radiograph which confirms a moderate pneumothorax, a pigtail catheter is placed by surgery and he is admitted. He undergoes chest CT showing bilateral apical blebs, pigtail was removed POD #2, and he is scheduled for follow up for surgical intervention.
Ultrasound offers increased sensitivity (98-99%) compared to chest radiograph in the detection of pneumothorax and similar specificity.
How to perform POCUS lung ultrasound for pneumothorax:
- Linear Probe
- Patient supine
- Place the probe with indicator toward the head (sagittal), perpendicular to the chest, in the mid-clavicular line at the 2nd-4th intercostal spaces (same location as for needle decompression of tension pneumothorax, as this is where air accumulates first when patient is supine).
- Assess for lung sliding in b-mode. Lung sliding, which is movement between adjacent parietal and visceral pleural layers, has been described as a shimmering appearance of the pleural line or “ants marching.” Lung sliding will be present in aerated lung and absent in pneumothorax, when there is air between the parental and visceral pleural layers.
- Press “M” for M-mode to look for seashore sign or barcode sign. “Seashore sign” will be present in aerated lung, and “barcode sign” will be present in pneumothorax.
- Assess for lung point- move probe superior and inferior over adjacent lung spaces to look for the lung point, which is the edge of the pneumothorax where the parietal and visceral pleural join together with aerated lung below. The lung point is highly specific for pneumothorax but may not be visualized in large pneumothoraces with complete lung collapse (see attached video clip example).