A 56 year old man presents to the Emergency department from another hospital for trauma assessment. Earlier that morning he had fallen off a roof and injured his chest and left hand. He has had 3 chest ultrasounds performed by 3 different operators and a pneumothorax was missed. It was picked up by a CT scan. So what went wrong?
Air will accumulate at the highest point in the chest. This becomes important when detecting a small pneumothorax otherwise it will be missed.
Below no pneumothorax detected. Probe is not placed at the highest point in the chest.
Transition point of pneumothorax
Note that the small pneumothorax is detected low down on the anterior chest wall at the highest point point of the chest. Air moves up when a patient is supine to the highest point of the chest.
No pneumothorax detected Pneumothorax detected Lateral transition point
Teaching point: A small pneumothorax will be missed if the probe is not placed correctly on the chest. Air will accumulate at the highest point in the chest. Place the probe there first or simply slide the probe down the chest wall until you are sure you have covered the entire chest wall anteriorly in the mid clavicular line.