Performance of automated external defibrillators under conditions of in-flight turbulence

Introduction Modern automated external defibrillators (AEDs) are designed to prevent shock delivery when excessive motion produces rhythm disturbances mimicking ventricular fibrillation (VF). This has been reported as a safety issue in airline operations, where turbulent motion is commonplace. We aimed to evaluate whether all seven AEDs can deliver shock appropriately in a flight simulator under turbulent conditions. Methods The study was performed in a Boeing 747-400 full motion flight simulator in Hong Kong. An advanced life support manikin and arrhythmia generator were used to produce sinus rhythm (SR), asystole, and five amplitudes of VF, with a programmed change to SR in the event of an effective shock being delivered. All rhythms were tested at rest (no turbulence) and at four levels of motion (ground taxi vibration, and mild, moderate and severe in-flight turbulence). Success was defined as: 1. effective shock being delivered where the rhythm was VF successfully converted to SR; 2. no inappropriate shock being delivered for asystole or SR. Results Five AEDs produced acceptable results at all levels of turbulence. Another was satisfactory for VF except at very fine amplitudes. One model was deemed unsatisfactory for in-flight use as its motion detector inhibited shocks at all levels of turbulence. Conclusion Some AEDs designed primarily for ground use may not perform well under turbulent in-flight conditions. AEDs for possible in-flight or other non-terrestrial use should be fully evaluated by manufacturers or end-users before introduction to service.