We presumed that pre-hospital advanced airway management might also be associated with improved outcomes because it would effectively improve the oxygenation of blood by assisting disordered respiration; however, in our study, advanced airway management was associated with poor outcomes. In Japan, CPR performed by EMS personnel is, in principle, CPR with bag valve mask ventilation. Thus, the results of our study showed that CPR with advanced airway management had poorer outcomes than CPR with bag valve mask ventilation. This result is similar to those from previous studies that included OHCA from causes other than respiratory disease. The EMS personnel’s unfamiliarity with intubation techniques, hyperventilation after advanced airway management and Hyperoxia are thought to be factors.