Intervention
SE
Participants were accompanied into a room by a study operator who was equipped with a smartphone (iPhone 2013, Apple Inc., USA). Based on a prior study, video quality had no significant impact on the evaluation of CPR performanceDuring the scenario, the participants should perform the initial examinations (check the safety of the environment, check the response and the breathing of the victim), give instructions to the study operator to call the ambulance and start chest compressions. Related to the duration of the intervention, the clock started when the participant entered the room. After that, every participant should perform chest compression-only CPR for 2 min (because based on the current guidelines changing the rescuer during CPR is recommended every 2 min)Another room was set up for the dispatcher with a smartphone (for audio communication; iPhone SE 2020, Apple Inc., USA) and a tablet (for video communication; iPad Air 8th Gen, Apple Inc., USA). Two dispatchers were involved in the study who were familiar and experienced with the Hungarian emergency dispatch system and were informed about the study methods. In the U-CPR group, the dispatcher gave the information to the caller that they should perform chest compressions until the ambulance arrives. After that, the call ended and no further instructions were received from the dispatcher. In the T-CPR and V-CPR groups, the dispatcher gave instructions related to high-quality chest compressions based on the current ERC guidelinesDuring the scenario, the smartphone and the tablet were linked to the internet via secure WiFi (bandwidth 1000 mbits