 Multiple clinical trials have been undertaken examining the safety and efficacy of the ETC King LT-D used in the pre-hospital setting. In general, the ETC device has shown superiority to the laryngeal mask airway LMA, oral airwaybagged mask ventilation, and the pharyngeal tracheal lumen airway in terms of success rate of insertion, ventilation, and complication rates. In-hospital use, including use in elective operative cases up to 6 hours duration and in cardiac arrest necessitating CPR, has been studied in a more limited fashion. However, small clinical trials have supported the use of ETC King LT-D as a first line rescue airway when ETT is not possible. In addition, several studies have shown equivalence of ventilation and oxygenation between ETT and ETC used in CPR, in the operating suite, and in the ICU setting. However, most clinicians still view the supralaryngeal ETCKing LT-D as primarily rescue airways. 