Dispatch of Emergency Call Using Video Streaming Compared With Traditional Telephone Communication (CAM-VISION)

Criteria-based Ambulance Management - Video Indexation VS Standard Indexation On Non-selected Emergency Calls

In the Emergency Medical Dispatch Center, all EMS dispatchers were divided into one of two clusters with 11 EMS dispatchers in each cluster. Because of few clusters, a matched-pair (MP) design was used based on the average proportion of the dispatched level of urgency (highest level of urgency used as primary matching criteria), years of employment and the average duration of emergency calls in a 3-months period (1st of January 2022 - 31st of March 2022) before the implementation of video streaming. Newly employed personnel where matching was not possible were randomly assigned to one of the two clusters. Prior to the study period, video streaming was gradually implemented in the intervention group during a 6-months period (1st of July 2022 - 31st of December 2022). Using a cluster randomized setup, the aim was to investigate differences in the management of emergency calls (dispatches) when emergency medical service (EMS) dispatchers use video streaming compared with telephone-only (audio-only) communication. All emergency calls will be randomly distributed between the two clusters.

In Denmark, all emergency medical calls are answered by a nurse- or paramedic trained in dispatching emergencies. The EMS dispatcher determines the level of urgency and the type and number of resources to be allocated (e.g., ambulance, physician-manned vehicle and/or physician-manned helicopter (HEMS). The decision-making process is supported by a standardized national criteria-based dispatch tool called Danish Index for Emergency Care (DI). DI is a tool that classifies the patient's main complaint into different symptom groups (chapters) to determine the level of urgency required and which resources to allocate. As standard, emergency calls are based on telephone-only (audio-only) communication, which might limit the understanding of a complex clinical presentation. Previous studies suggest that a visualized clinical presentation could aid the EMS dispatchers in their decision-making and dispatch. The decision on implementing video streaming has been made by the management board of the Prehospital Emergency Medical Services, Central Denmark Region, Denmark. It has been decided to implement video streaming gradually to allow for this cluster randomized study. Because video streaming is a deemed part of the standard operating procedure (SOP), ethical approval from our local ethical committee is waived. After the study period, video streaming will be implemented in the current control group as the decision to use video streaming as SOP has already been decided.

Emergency Medical Dispatch Centre, Video Streaming, Emergency Call, Prehospital Emergency Medical Services

The emergency caller (patient or bystander) is initially masked to the intervention (video or telephone communication) when initiating the call to the Emergency Medical Dispatch Center (EMDC). Emergency calls are randomly answered by an EMS Dispatcher using either video or telephone (audio-only) communication.

Intervention group: EMS dispatcher using video-based communication in emergency calls. In the intervention arm, the EMS Dispatchers are requested to use video in all emergency calls during the 4-month study period.

Control group: EMS dispatcher using telephone-only (audio-only) communication in emergency calls. In the control arm, the EMS Dispatchers continue using standard telephone communication (usual care).

Adding video streaming as a technical adjunct to the otherwise audio-based-only communication during emergency medical dispatch

Defined by the dispatch code generated by the computer-aided dispatch software Logis and stored in the EMDC database

Defined by the dispatch code generated by the computer-aided dispatch software Logis and stored in the EMDC database graded in 5 levels.

Number of participants where the levels of urgency are identical when comparing the ambulance to and from the scene

The number and proportion of participant where the level of urgency dispatched by the EMS dispatcher (determining the speed of the ambulance transport to the scene) is identical to the level of urgency determined by the EMS provider (determining the speed of the ambulance transport to hospital).

Number and proportion of emergency medical calls, where the EMS dispatcher change the level of urgency during the emergency medical call.

Change in allocated resources (e.g., number of ambulances, helicopter, physician manned vehicles etc.) during the emergency call compared with the initially allocated resources.

Number of participants readmitted to hospital within 24 hours after a dispatch without hospital admission (lowest level of urgency - response level E)

The number and rate of readmission to hospital within 24 hours among emergency medical calls dispatched at lowest level of urgency (response level E) without allocated prehospital resources (patients only provided with an advice from the EMS dispatcher).

Time (in minutes) from the start of the emergency medical call to the dispatch (allocated resources with a level of urgency) by EMS dispatcher.

Number of participants achieving ROSC after cardiac arrest in the prehospital or in-hospital phase of treatment

Among patients surviving cardiac arrest, neurological outcome will be measured by cerebral performance category (CPC) obtained in the in-hospital electronical patient record 90 days after study inclusion. The CPC ranges from 1 to 5. 1 representing intact function and 5 representing brain death. Favorable neurological function is defined as CPC 1 or 2 and an unfavorable function as 3-5

Among patients with cardiac arrest, neurological outcome measured by modified Rankin Scale (mRS) obtained in the in-hospital electronical patient record 90 days after study inclusion. The mRS ranges from 0 to 6. 0 representing no symptoms and 6 representing death. Favorable neurological outcome is defined as mRS 0-2.

Recognition of stroke or transient ischemic attack (TIA) by the EMS dispatcher based on the criteria-based dispatch reference work (Danish Index, chapter 26 and the subheadings A03, A04 and B06)

Rate of revascularization treatment (intravenous thrombolysis and/or endovascular treatment (EVT)) among patients with acute ischemic stroke

Rate of acute stroke treatment (i.v. thrombolysis and/or endovascular treatment (EVT)) among patients with a timely contact to the EMDC (within 3 hours (thrombolysis) and 24 hours (EVT)).

Onset-to-treatment times for patients with acute ischemic stroke treated with i.v. thrombolysis and onset-to-groin-puncture for patients treated with EVT.

Time from symptom onset (stroke symptoms) to initiated treatment in-hospital with either iv. thrombolysis or EVT.

Number and proportion of children (< 15 years of age) dispatched lowest level of urgency (not admitted to hospital and only provided with an advice from the EMS dispatcher)

Re-admissions among children (< 15 years of age) to hospital within 24 hours from a prior emergency call dispatched with lowest level of urgency (response level E)

Re-admissions to hospital within 24 hours from a prior emergency call among children (< 15 years of age) initially dispatched with lowest level of urgency (response level E only provided an advice from the EMS dispatcher)

Defined by the dispatch code generated by the computer-aided dispatch software Logis and stored in the EMDC database

Inclusion Criteria: Emergency call to the EMS dispatcher in the EMDC EMS dispatcher employed in the total study period EMS dispatchers with a completed training period (6 weeks total) at the start of the study period Exclusion Criteria: Emergency calls directed to an EMDC physician or technical logistical personnel not using the criteria-based dispatch tool non-emergency calls (health care provider requested prehospital transports) EMS dispatcher not employed in the total study period EMS dispatchers without a completed training period (6 weeks total) at the start of the study period