Short, vertical, linear radio-opaque marker of an intra-aortic balloon pump seen projected over the AP window in a patient who has had an out of hospital cardiac arrest and was being managed in ITU. Two separate chest radiographs of this same patient where taken on the same day. The first one demonstrated the balloon in the deflated position, and the second demonstrated the balloon inflated (hyperlucency filling the descending thoracic aorta, see annotated image below).
Other findings in these films include adequately positioned ET tube, right jugular venous line at the brachiocephalic vein/ SVC junction, NG tube with tip and side holes in stomach, ECG lead artefacts and bilateral perihilar thickening.