Abstract Sun907: <i>Feasibility and Safety of AED Drone Manual Delivery in Nighttime: A Quasi-Experimental Study</i>

Background: Outdoor nighttime mass gatherings pose challenges for OHCA responses. While drone AED delivery shows promise in daytime (Jakobsen et al., 2024), this study’s major objective was to compare the feasibility (flight performance) and safety of manual AED drone deliveries (incident rates) by paramedics during daytime versus nighttime. Only one prior study (Scholz et al., 2023) evaluated automated nighttime operations, leaving manual flights understudied. Methods: (Update) A quasi-experimental within-subjects trial was conducted in Hong Kong’s High Island Reservoir (semi-urban, light-pollution-free) from January–March 2024. Twelve advanced-certified paramedic pilots (mean age 34 ± 5.2 years, 10 male, 2 female) manually operated a DJI M30T drone (3.9 kg) equipped with infrared/night vision, strobe lights, and a 480g AED across 800m during 12 daytime and 12 nighttime flights. The sample size of 12 per group followed the pilot study design recommendation (Julious, 2005) Primary outcomes were flight time (seconds) and incident rates; exposure was time-of-day (day/night). Flights followed EVLOS protocols with safety officers. Paired t-tests compared flight times; chi-square assessed incident differences. Ethical approval was obtained from Hong Kong Metropolitan University and under the approval of the Hong Kong Civil Aviation Department. Results: All 24 flights (12 pilots × 2 conditions) concluded without incidents or obstacle triggers. Mean flight times were 136 ± 8.71s (day) vs. 139 ± 14.16s (night), with an unadjusted mean difference of 3.92s (95% CI: -6.1 to 13.9; p=0.43; Cohen’s d=0.24). Incident rates did not differ (0% vs. 0%, p&gt;0.05). Paramedics Pilots reported comparable situational awareness during nighttime operations, attributing confidence to infrared navigation and strobe lighting systems. Conclusions: Manual nighttime AED drone delivery with lights is feasible and safe, with performance parity to daytime. Infrared technology and trained paramedic pilots enable scalable 24/7 deployment, potentially reducing OHCA mortality disparities. Findings directly support integrating drones into mass-gathering emergency protocols. Future full scale studies should validate findings.