This proposal is submitted in response to RFA-HL-14-019 Low-Cost, Pragmatic, Patient-Centered Randomized Controlled Intervention Trials. Cardiopulmonary arrest is the critical illness resulting from sudden cessation of heart function and circulatory blood flow. Sudden out-of-hospital cardiopulmonary arrest (OHCA) is a major public health problem, affecting over 300,000 persons in the United States each year, with only 8% surviving. Successful cardiac arrest resuscitation requires delivery of life-saving oxygen to the heart and brain. Airway management is the process of opening the mouth and throat to deliver oxygen to the lungs for circulation to the vital organs. Paramedics commonly accomplish airway management using endotracheal intubation (ETI), the insertion of a plastic breathing tube through the mouth and into the trachea. However, paramedic ETI is risky and resource intensive. Supraglottic airways (SGA - such as the King Laryngeal Tube, Combitube, and Laryngeal Mask Airway) are simpler alternatives but have unproven outcomes. The best strategy for OHCA airway management remains unknown. We propose a multicenter pragmatic clinical trial comparing 1) ETI with 2) SGA airway management in paramedic resuscitation of adult OHCA. We will carry out the trial using the massive existing infrastructure of the NHLBI-funded Resuscitation Outcomes Consortium (ROC), a highly successful 10-city collaborative specializing in OHCA trials. The aims of the study are: Specific Aim I: Prepare the Resuscitation Outcomes Consortium for execution of a pragmatic trial of airway management strategies in out-of-hospital cardiopulmonary arrest. Per the RFA, we will complete preparatory tasks necessary to carry out the trial. Specific Aim II: Determine the effect of paramedic airway management strategy (SGA vs. ETI) upon outcomes after adult OHCA. We will test the hypothesis that rates of OHCA 72-hour survival are higher with SGA- than ETI-based airway management strategies. This landmark trial will answer one of the most urgent and controversial clinical questions in OHCA care; What is the best way to manage the airway? The study findings will have immediate and lasting impact upon paramedic clinical practices internationally. ROC is the only network in the world poised to efficiently carry out a trial of this design and magnitude. The study will be spearheaded by the world's leading experts in out-of- hospital airway management and cardiopulmonary arrest.