Pericardial effusions in children have multiple causes and variable presentations. Cardiac tamponade occurs when the heart chambers become externally compressed and ultimately cardiac output is compromised. The classical signs of cardiac tamponade include jugular venous distention, muffled heart sounds, and systemic hypotension (“Beck’s triad”); however, these are rarely all present. As cardiac output is dependent on preload and heart rate, the anesthetic goal is to avoid cardiac depression, maintain sympathetic outflow, and avoid a decrease in preload. If the effusion is amenable to percutaneous drainage, ideal anesthetic management includes sedation and analgesia with local anesthetic, while keeping the patient spontaneously breathing. If an open procedure is required, it is advisable to perform a “staged” anesthetic and surgical approach in which sedation, analgesia, and local anesthetic are administered to drain the effusion percutaneously before inducing general anesthesia and starting positive-pressure ventilation. As in most emergency situations, the risks of pulmonary aspiration and the chosen anesthetic techniques must be weighed against the urgency of intervention.