Medical Drones: Transporting AEDs in rural areas

A new study suggests that drone-delivery of AEDs to cardiac arrest scenes could reduce unequal emergency response times between urban and rural areas.

This article was translated and adapted from the original Italian version.

Survival rates are still low in OHCA cases

Every year, over 300,000 people suffer from out-of-hospital cardiac arrest (OHCA) in Europe. Only 8–10% survive. According to the American Heart Association, more than 350,000 cardiac arrests occur outside of the hospital each year, with a survival rate of only about 10%.

However, given the evidence and best practices in some countries, survival rates of 50% or more could be achieved if basic life support and defibrillation (BLSD) procedures were immediately implemented by first responders.

The strong need to optimize care for OHCA patients is clear. In many nations, AEDs (automated and semi-automatic external defibrillators) with public access are not widely available, especially in rural regions. The rate of defibrillator use prior to the arrival of emergency vehicles on individuals suffering from cardiac arrest in out-of-hospital settings is still too low, probably due to low community awareness of the problem. New strategies are therefore needed to overcome this deficiency.

Using drones to transport defibrillators

Several recent studies have demonstrated the feasibility, safety and efficiency of transporting AEDs by UASs (Unmanned Aircraft Systems), known to most people simply as 'drones'. These studies also confirmed that the use of drones could significantly reduce the time needed for early defibrillation, especially in sparsely populated rural regions.

The cardiac arrest research group at the Karolinska Institute in Stockholm has shown that delivering an AED by air to the scene of cardiac arrest is possible, safe and potentially faster than the ambulance service. In their most recent study, they succeeded in integrating AED-UAS into the normal emergency system rescue chain.

These convincing results prompted the European Resuscitation Council and the International Liaison Committee on Resuscitation to consider AED delivery by air in their recent guidelines.

Early defibrillation: can drones mitigate differences between urban and rural areas?

According to preliminary research led by Dr Jamal Chu of the University of Toronto and to be presented at the American Heart Association's Resuscitation Science Symposium 2023 in mid-November, a drone delivery system could improve access to AEDs in the event of out-of-hospital cardiac arrest.

For the study, researchers developed a simulation model that assessed how quickly an AED could be delivered to the scene of a cardiac arrest in nineteen North Carolina counties. The study method used data from the Cardiac Arrest Registry to Enhance Survival (CARES) database and identified OHCA cases in 48 counties from January 2013 to December 2019.

A hypothetical intervention was envisioned in which 1) all first responders had AEDs available and 2) a network of AED transport drones was optimised in each county to minimise the response time of less than 5 minutes. The latter was defined as the interval between receipt of the 9-1-1 emergency number call and the arrival of an AED via emergency medical service, first responder or drone.

Image credit: American Heart Association

Surprising results: urban areas still benefitted more

The results showed historical median response times of 6.9 minutes in urban areas and 9.4 minutes in rural areas. The deployment of first responders and drones reduced the estimated median response time by 42% to 4.0 minutes in urban areas and by 24% to 7.1 minutes in rural areas. Coverage within 5 minutes improved from 24% to 77% in urban areas and from 10% to 23% in rural areas. All counties showed a significant improvement in response times for both urban and rural populations.

The study found that the use of drones to deliver AEDs in OHCA led to more significant improvements in urban areas than in rural areas. This result was surprising because the researchers expected drones to reduce the disparity in response times between urban and rural areas, where emergency medical system response times are often longer.

The explanation might lie in the fact that the study used an optimisation model to maximise the number of out-of-hospital cardiac arrests that received a response within 5 minutes, but since historical response times were generally longer than 5 minutes in both urban and rural areas, the algorithm prioritised the more populated urban areas, which are more easily reached by drones.

The road ahead

The authors point out that the transition from computational theory to the practical implementation of drones entails significant challenges related to regulations and infrastructure. Furthermore, the success of the system will depend on collaboration between drone operators and the community, including education programmes that teach people how to use AEDs effectively.

In summary, the use of drones to deliver AEDs in cases of cardiac arrest has the potential to save lives, but practical challenges need to be carefully considered and the approach tailored to demographics, geography and historical response times of each region to ensure effective and equitable implementation.

  1. Jamal Chu, Benjamin Leung, Univ of Toronto, Toronto, ON, Canada; Audrey L Blewer, Duke Univ, Durham, NC; Konstantin Krychtiuk, Duke Clinical Res Inst, Durham, NC; Darrell Nelson, Wake Forest Sch of Med, Winston-Salem, NC; Stephen Powell, Wake Forest Sch of Med, Winston Salem, NC; Bryan F McNally, Emory Univ Sch of Med, Atlanta, GA; Christopher B Granger, Duke Clinical Res Inst, Durham, NC; Joseph P Ornato, Virginia Commonwealth Univ, Richmond, VA; Daniel B Mark, Duke Univ Medical Ctr, Durham, NC; Timothy Chan, Univ of Toronto, Toronto, ON, Canada; Monique A Starks, Duke Univ, Durham, NC. Rural-Urban Differences for Integrated First Responder and Drone Automated External Defibrillator Delivery in North Carolina. American Heart Association Resuscitation Science Symposium 2023, Abstract 105