A 67-year-old man with stage III lung cancer complicated by lung abscesses was receiving fluid resuscitation for dehydration through a left subclavian port when he developed sudden onset of confusion and left-sided weakness. The patient gradually became less responsive, and a computed tomographic scan of the head demonstrated air in the cerebral veins (Figure, B) as well as incidental cerebral atrophy. A venous source was suspected, and a computed tomographic scan of the chest confirmed air in the right subclavian vein (Figure, A). The patient did not improve, despite receiving hyperbaric oxygen. Magnetic resonance imaging of the head demonstrated a gyriform pattern of ischemic changes (Figure, C) consistent with air emboli.1