Opioids are responsible for the greatest drug-related global health burden. Prevention and treatment programs for people with opioid use disorder are widely implemented, but further actions are required to reduce the mortality and morbidity caused by opioid use and dependence. We suggest a novel and unique approach with a volunteer first responder system for suspected opioid overdoses, integrated with national emergency call services. The idea derives from the success of volunteer first responder systems for out-of-hospital cardiac arrests. Several reports exist globally with results of increased survival rates, less complications and a beneficial time-gain to start of cardiopulmonary resuscitation before emergency services (like ambulance and fire fighters) arrival.

Our model aims to investigate feasibility, acceptability and safety of a smartphone-based volunteer first responder system for suspected opioid overdoses. The volunteer responders will be equipped with an emergency kit including two doses of the opioid antidote naloxone, which can reverse life-threatening respiratory arrest caused by intoxication of opioids. The responders will, prior to registration, accomplish an in-depth overdose and naloxone education, as well as a first aid course aligned with current European and Swedish resuscitation guidelines. The results will be collected through questionnaires to the responder participants, technical data from the responder application, and dispatcher, pre-medical/paramedical and hospital records among others. Both quantitative and qualitative methods will be used. The major question is if the model is feasible in alerting lay persons with naloxone to suspected overdose situations and successfully administer naloxone prior to emergency service arrival. Furthermore, experiences of safety during alerts among volunteer first responders and overdose victims will also be studied.

Our model is unique in its integration with emergency medical dispatch service along with overdose and first aid education prior to participant registration. The respiratory arrest of opioids is an acute life-threatening condition, which - in similarity to cardiac arrests - need emergent actions for survival. A reduced time to naloxone administration through volunteer first responders prior to ambulance arrival could save lives.

The accuracy of opioid overdose recognition among medical dispatchers is as of today an underexplored field. The risk of naloxone-responders being alerted to other medical emergencies than opioid overdoses is as a consequence unknown. The first aid course aims to improve the knowledge and emergency management of responders who get alerted to false positive opioid overdoses, while the naloxone and overdose in-depth education aims to help responders to properly identify and manage true overdoses.

Naloxone reverses opioid effects temporally, which calls for prolonged medical assistance with observation and sometimes repeated doses of naloxone at the hospital. The integration of naloxone-responder alerts and emergency medical service dispatching when bystander call the national emergency number is therefore a model with both short- and long-term management of overdose conditions.

The RESPONDER trial is a two-year pilot project with a one-year follow-up of each registered participant, so called naloxone-responder. At least four different follow-up sub-studies will be performed during and 1-2 years after the pilot period:

1. A quantitative study of feasibility, acceptability and safety of the intervention.
2. A quantitative study on mortality post-pilot as primary outcome, and clinical outcome after intervention compared to no intervention as secondary outcome.

3 and 4. Two qualitative studies exploring the experiences of: A. receiving naloxone from a naloxone-responder, from the overdose survivors' point of view, and B. accepting overdose alerts as a naloxone-responder, respectively.

Inclusion Criteria for volunteer first responder:

1. Give informed written consent to participate in the study
2. Successfully complete an opioid overdose and naloxone course in addition to a first aid course, following current first aid guidelines from the Swedish Resuscitation Council and the European Resuscitation Council.
3. Download and register oneself as a user on the project-specific volunteer first responder app on a smartphone
4. Purchase naloxone from a pharmacy and receive reimbursement for the full cost of the purchase upon submission of the pharmacy receipt

Exclusion Criteria for volunteer first responder:

1. Displaying inappropriate behavior during the education day (or otherwise in time, as witnessed or experienced by course instructors or the project team). Such conduct could for example be to not follow the guidelines of low-arousal (non-confrontational) approach in emergencies.

Inclusion Criteria for overdose alerts:

1. Victim being ≥15 years old
2. Any naloxone-responder being up to 10.000 meters from the situation, in Skåne

Exclusion Criteria for overdose alerts:

1. Any trauma behind the condition
2. Dispatcher impression of the scene to be unsafe for lay persons