In Japan, advanced airway devices (Combitube, Laryngeal mask airway and Laryngeal Tube) have been used by Emergency Life-Saving Technicians (ELSTs) since 1991, and specially-trained ELSTs have been permitted to use ETI since 2004 [3]. The use of advanced airway devices in Japan, including ETI for OHCA patients, has increased year by year [4]. However, it is still unclear whether survival from OHCA is improved by the use of ETI instead of the SGA