The use of veno-arterial extracorporeal membrane oxygenation (VA ECMO) has increased substantially over the past few decades. Today's clinicians now have a powerful means with which to salvage a growing population of patients at risk for cardiopulmonary collapse. At the same time, patients supported with VA ECMO have become increasingly more complex. The successful use of VA ECMO depends not only on selecting the appropriate patients, but also on effectively navigating a potential torrent of device- and patient-related complications until ECMO is no longer needed. A multitude of monitoring tools are now available to help the treatment team determine the adequacy of care, to detect problems, and to anticipate recovery. Monitoring with devices such as the Swan-Ganz catheter, transthoracic and transesophageal echocardiography, chest radiography, and near-infrared spectroscopy can provide useful information to complement routine clinical care. Leveraging data derived from the ECMO circuit itself also can be instrumental in both evaluating the sufficiency of support and troubleshooting complications. Each of these tools, however, has its own unique sets of limitations and liabilities. A thorough understanding of these risks and benefits is critical to the contemporary care of the individual managed with VA ECMO. In addition, more research is needed to establish optimal evidence-based care pathways and best-practice principles for using these devices to improve patient outcomes.