Drone Delivery of Automated External Defibrillators to Lay Users (DAEDALUS): A Proof of Concept Study

STUDY PROTOCOL: Drone Delivery of Automated External Defibrillators to Lay Users (DAEDALUS): A proof of concept study

1. BACKGROUND Out-of-hospital cardiac arrest (OHCA) is a medical emergency where the heart suddenly stops beating, causing a cessation of blood flow to vital organs. Many cardiac arrests are triggered by the heart entering an abnormal rhythm, known as an arrhythmia, which disrupts its ability to pump blood effectively. Defibrillation, the process of delivering an electric shock to the heart using an Automated External Defibrillator (AED), can correct this abnormal rhythm and restore normal heart function, significantly improving the chances of survival when administered promptly (1, 2). AEDs are designed to be simple to use, with prompts guiding untrained bystanders through applying the device and performing CPR. Quick access to an AED can increase the chances of survival by 50-70% (3), and each minute without defibrillation reduces survival rates by approximately 10%. In the UK, over 30,000 OHCAs occur each year, but survival rates remain below 10%, largely due to delays in administering defibrillation (4).

Public access AEDs are placed in busy public areas to assist bystanders during a cardiac arrest before ambulance services arrive, significantly increasing the chances of survival (5). However, their effectiveness is limited by the accessibility and speed at which they can be retrieved and used, particularly in residential areas where 80% of cardiac arrests occur (6). AED usage remains low (<5%) because most cardiac arrests happen at home, where AEDs are rarely available (7). This highlights the critical need for solutions that can rapidly deliver AEDs to residential locations. Only 2% of out-of-hospital cardiac arrests (OHCAs) in residential settings result in successful resuscitation (8). The disparity in survival rates between public and private settings underscores the need for solutions to ensure AED deployment, including in residential areas. Only 48% of 999 calls for cardiac arrests meet the target response time of an ambulance arriving with an AED in 7 minutes (9). A new solution is therefore much needed, and this project is timely. 2. RATIONALE Drones offer a promising solution by enabling rapid AED delivery. However, while drone-based AED delivery systems have shown potential in other countries like Sweden, the UK has unique regulatory, logistical, and cultural factors that have yet to be explored or addressed.

Our study fills this gap by focusing specifically on integrating drones into the UK's emergency response system, accounting for UK airspace regulations, NHS ambulance service protocols, and public perception within the UK cultural context. This research aims to ensure that drone-delivered AEDs are integrated into real-world practice, ultimately improving the rate of defibrillation, decreasing the time to defibrillation and improving survival.

A key aspect of what sets our study apart from any previous study is the collaboration with the UK Civil Aviation Authority (CAA), Kent Surrey Sussex Air Ambulance (KSS), and Everdrone. The CAA is the UK's aviation regulator, responsible for providing oversight of all air traffic and drone operations within UK airspace, and importantly, we have CAA approval for this project. KSS, the air ambulance service for the region, will be the organisation running the drone service in this study, ensuring it is integrated with NHS emergency response systems. Everdrone, a Swedish company with extensive experience in medical drone technology, will pilot the drones and provide technical support.