Percutaneous mechanical assist devices are used in patients with cardiogenic shock. The purpose of this article is to familiarize critical care nurses with the various types of percutaneous mechanical assist devices, including the intra-aortic balloon pump, the Impella device, extracorporeal membrane oxygenation, and the TandemHeart device. Each type of device requires specific nursing care. In a patient with cardiogenic shock, the monitoring, care, and interventions provided by an experienced critical care nurse can make the difference between survival and death.