Superior-head automated external defibrillator placement during single-rescuer cardiopulmonary resuscitation: a randomized crossover simulation study and retrospective multicenter cohort.

Background: During single-rescuer cardiopulmonary resuscitation (CPR), one rescuer must sustain chest compressions while operating an automated external defibrillator (AED), yet the optimal physical position of the AED within the rescuer's working area is uncertain. The study evaluated whether superior-head AED placement improves the single-rescuer defibrillation workflow. Methods: The study combined a randomized four-sequence crossover manikin simulation (32 healthcare providers; 128 evaluable trials) comparing four prespecified AED positions-superior-head placement (position D) versus alternative placements (positions A-C)-with a retrospective cohort of 213 AED-treated adult cardiac-arrest cases from six centers (57 with position D, 156 with other positions). The primary simulation outcome was compression-to-first-shock time; the primary clinical outcome was the collapse-to-first-shock interval. Secondary outcomes included AED-related hands-off time, chest compression fraction, NASA Task Load Index workload, and procedural safety. Results: In the simulation, position D shortened compression-to-first-shock time by 14.8-26.3 s relative to the other positions (all Holm-adjusted Conclusion: Superior-head AED placement improved the efficiency, compression continuity, and workload of simulated single-rescuer CPR. The retrospective clinical findings were directionally consistent but statistically inconclusive and should be regarded as hypothesis-generating rather than confirmatory. Prospective validation is required before clinical implementation.