We present a case of massive fluid overload as a result of chronic lupus-related constrictive pericarditis, which was treated in the emergency department (ED) with ultrafiltration. With this novel technique, a large volume (7,350 mL) was extracted during 19 hours, with dramatic clinical improvement. The patient was hemodynamically stable throughout the intervention, and the procedure was tolerated without complication. This report highlights the challenges associated with the treatment of such individuals and the potential benefits of ultrafiltration in the ED setting.