Randomisation, study procedure, and interventions
FIRE
During the emergency call, the dispatchers in the central dispatching centre of the fire department in Aachen typed the suspected symptoms into the dispatching software (Cobra 4, ISE GmbH, Aachen, Germany). An algorithm in the dispatching software initiated randomisation automatically if essential operational conditions were met, e.g. availability of an EMS physician in both study arms and the entered symptom matched a severe condition according to the EMS physician indication catalogue of the German federal medical association. Patients were allocated to receive either tele-EMS (tele-group) or conventional physician-based EMS (control group) using complete randomisation with a 1:1 allocation ratio. Before implementation of the tele-EMS physician for each of the patients, an EMS-physician was alerted. Since implementation, a parallel alert can only be dispensed because the paramedics can consult the tele-EMS physician by pushing a button. The dispatcher assigned the patients to their respective groups as randomised. A manual conversion of the initial assignment in terms of the tele-group was required, if in the further course of the phone call the dispatcher assumed a life-threatening emergency. Further, the initially dispatched team was always allowed to pass the mission to the other group on both sides based on the situational assessment.