Lung Point | Point of Care Ultrasound

M-MODE APPEARANCE OF PNEUMOTHORAX

When using m-mode in patients with pneumothorax, the sea shore appearance is no longer present. In the pleural line, lung sliding no longer occurs and the sand like appearance below the pleural line is replaced by multiple lines giving the appearance of barcode or stratosphere sign.

Look at the pleural line. There is lung sliding seen on the right of the image. There is no lung sliding on the left. The point where the 2 meet is called the lung point.

Clinical Importance of the Lung Point: It is important to determine the size of the pneumothorax. The location of the lung point may assist in determining the size of the pneumothorax. If a lack of lung sliding is visualized anteriorly, the probe can progressively be moved to more lateral and posterior positions on the chest wall searching for the location of the lung-point. The more lateral or posterior the ‘lung-point sign’ is identified, the larger the pneumothorax.

Therefore, if the ‘lung-point sign’ is seen in an anterior location on the chest wall, the pneumothorax is relatively small. The lung point sign had an overall sensitivity of 66% and a specificity of 100%. Keep in mind that the sensitivity may be low because in large pneumothoraces, the lungs are so collapsed that there is no point when the inflated lung is in contact with the parietal pleura.

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