A 56-year-old man was brought to the ED after being found unconscious on the street. The initial neurologic exam resulted in a Glasgow Coma Scale score of 3. After endotracheal intubation for airway protection, a CT scan of the head revealed a large left-side intracranial hemorrhage with a 5-mm midline shift and the patient was transferred to our medical ICU for management. Soon after arrival, central venous access was attempted via a left subclavian vein approach because of insufficient peripheral access sites. Immediately after the procedure, severe hypotension (BP =62/46) and desaturation (oxygen saturation =65%) developed. Concern for an iatrogenic tension pneumothorax led to immediate preparation for needle decompression and chest thoracostomy-tube placement. During preparation, a team member performed a physical examination and a left-side chest ultrasound survey. Physical examination revealed presence of equal, bilateral breath sounds and the symmetric appearance of hemithorax dimensions. Ultrasound findings are shown in Videos 1-3.