  Responding to emergencies in Alpine terrain is quite challenging as air
ambulances and mountain rescue services are often confronted with logistics
challenges and adverse weather conditions that extend the response times
required to provide life-saving support. Among other medical emergencies,
sudden cardiac arrest (SCA) is the most time-sensitive event that requires the
quick provision of medical treatment including cardiopulmonary resuscitation
and electric shocks by automated external defibrillators (AED). An emerging
technology called unmanned aerial vehicles (or drones) is regarded to support
mountain rescuers in overcoming the time criticality of these emergencies by
reducing the time span between SCA and early defibrillation. A drone that is
equipped with a portable AED can fly from a base station to the patient's site
where a bystander receives it and starts treatment. This paper considers such a
response system and proposes an integer linear program to determine the optimal
allocation of drone base stations in a given geographical region. In detail,
the developed model follows the objectives to minimize the number of used
drones and to minimize the average travel times of defibrillator drones
responding to SCA patients. In an example of application, under consideration
of historical helicopter response times, the authors test the developed model
and demonstrate the capability of drones to speed up the delivery of AEDs to
SCA patients. Results indicate that time spans between SCA and early
defibrillation can be reduced by the optimal allocation of drone base stations
in a given geographical region, thus increasing the survival rate of SCA
patients.
