This study is a Phase 3, multi-center, Bayesian Adaptive Sequential Platform Trial testing the effectiveness of different prehospital airway management strategies in the care of critically ill children. Emergency Medical Services (EMS) agencies affiliated with the Pediatric Emergency Care Applied Research Network (PECARN) will participate in the trial. The study interventions are strategies of prehospital airway management: \[BVM-only\], \[BVM followed by SGA\] and \[BVM followed by ETI\]. The primary outcome is 30-day ICU-free survival. The trial will be organized and executed in two successive stages. In Stage I of the trial, EMS personnel will alternate between two strategies: \[BVM-only\] or \[BVM followed by SGA\]. The \[winner of Stage I\] will advance to Stage II based upon results of Bayesian interim analyses. In Stage II of the trial, EMS personnel will alternate between \[BVM followed by ETI\] vs. \[Winner of Stage I\].