Jon-Emile S. Kenny MD [@heart_lung] with illustrations by Carla M Canepa MD [@_carlemd_] “History does not repeat itself, but it often rhymes.” -Mark Twain Case An 89 year old man with a 100 pack-year smoking history is admitted with weakness and inability to take anything by mouth. He was discharged 2 months prior after a treatment course for C. difficile colitis. He returns to the ED with confusion. On examination his eyes are sunken and has poor capillary refill. He is very thin, with a ‘pink-puffer’ phenotype and a ‘systolic murmur.’ His blood pressure is lower than his normal grade II hypertension and his blood work reveals acute kidney injury. The admitting medicine resident evaluates the patient’s IVC and finds it to be 1.5 cm in diameter with minimal respiratory variation – with this data, he withholds IV fluids and calls his attending.