Results

The initial search identified 696 articles, out of which 12 studies were included into the final analysis. The details of the selection process are reported in the PRISMA-ScR^{Reference Tricco, Lillie and Zarin24} flow diagram (Figure 1). Selected studies presented data from simulations (n = 7) and real prehospital clinical setting (n = 5). Most articles used quantitative (n = 7), qualitative (n = 2), or mixed (n = 3) methods. The design and main topics in the final sample of studies are summarized in Table 1. All extracted information about each article, study population, participants, and context with main aims of trials and key findings, are summarized in Table 2. Six main themes together with eleven subcategories were identified in synthesis of results (Table 3).

Figure 1.

PRISMA Flow Diagram for the Scoping Review Process.

Table 1.

Characteristics of Sources of Evidence

Abbreviations: CPR, cardiopulmonary resuscitation; OHCA, out-of-hospital cardiac arrest; HEMS, helicopter Emergency Medical Services.

Table 2.

Results of Individual Sources of Evidence

Abbreviations: AC, audio emergency call; AED, automated external defibrillator; HEMS, helicopter Emergency Medical Services; CPR, cardiopulmonary resuscitation; OHCA, out-of-hospital cardiac arrest; ROSC, return of spontaneous circulation; VC, video emergency call.

Table 3.

Coding Categories and Subgroups

Abbreviations: AED, automated external defibrillator; CPR, cardiopulmonary resuscitation; OHCA, out-of-hospital cardiac arrest.

Overall, a better quality of CPR delivered by a layperson was consistently observed in the VC groups in trials from both simulation and real-life settings.^{Reference Stipulante, Delfosse and Donneau9,Reference Ecker, Lindacher and Adams29–Reference Lee, Kim and Lee32} The delays in the initiation of CPR when using VC, described previously,^{Reference Stipulante, Delfosse and Donneau9} were not reproduced in recent studies.^{Reference Lee, Kim and Lee32–Reference Lee, You and Jeon34} In addition, VC compared to AC improved overall operational automated external defibrillator (AED) performance in the two simulation studies.^{Reference Kim, Kim and Park30,Reference Bang, Cho, Cho, Lee and Kim35} Nonetheless, a positive impact on patient-centered outcomes of VC in OHCA was observed in only one study (ROSC 29.7% versus 13.9%; survival to discharge 27.1% versus 12.3%; and favorable neurological outcome 19.4% versus 6.8% for the VC and AC groups, respectively)^{Reference Linderoth, Rosenkrantz and Lippert31} while clinical outcomes in previous study were negative.^{Reference Lee, Song and Shin33}

In clinical trials, the criteria to initiate VC from the field were based on presence of at least two bystanders on site, informed consent, and willingness of bystander to accept and stream video to the EMDC.^{Reference Ter Avest, Lambert and de Coverly12,Reference Linderoth, Lippert and Østergaard13,Reference Linderoth, Rosenkrantz and Lippert31,Reference Lee, Song and Shin33,Reference Lee, You and Jeon34} The initial part of an emergency call starts usually as an AC, and after identification of event (ie, CPR or helicopter Emergency Medical Services [HEMS]) and determining the type of response, the VC is initiated.^{Reference Ter Avest, Lambert and de Coverly12,Reference Linderoth, Lippert and Østergaard13,Reference Linderoth, Rosenkrantz and Lippert31} It seems to be advantageous to use VC also in pediatric emergencies, disorders of consciousness, trauma, or for indications of HEMS.^{Reference Ter Avest, Lambert and de Coverly12,Reference Linderoth, Lippert and Østergaard13} Dispatchers evaluated VC as very helpful in 89%, but not necessary in many calls (short arrival times, general medical events).^{Reference Linderoth, Lippert and Østergaard13}

Dispatchers’ assessment of the severity of patients’ conditions changed in high rate after live video was added to an emergency call and helped to appropriate response (ambulance type, HEMS).^{Reference Ter Avest, Lambert and de Coverly12,Reference Linderoth, Lippert and Østergaard13} Dispatchers can, due to VC, identify common rescuers errors: hands positioning during CPR;^{Reference Ecker, Lindacher and Adams29,Reference Linderoth, Rosenkrantz and Lippert31} safety issues during simulated defibrillation with AED;^{Reference Bang, Cho, Cho, Lee and Kim35} left and right side confusions on site; or recognize rescuer fatigue and suggest handover by other rescuer.^{Reference Ecker, Lindacher and Adams29,Reference Linderoth, Rosenkrantz and Lippert31,Reference Bang, Cho, Cho, Lee and Kim35} In real VC, there was only limited possibility to assess ventilation.^{Reference Linderoth, Rosenkrantz and Lippert31}

Dispatchers reported other phenomenon during VC in study of Linderoth, et al: unchallenging cooperation with caller in 89.3%; emotional stress of callers sometimes led to difficulty following instructions; increased workload due to longer VC than AC (on average 423 seconds versus 242 seconds); and necessity to change habits as the VC can interfere with current dispatching protocols or classifications.^{Reference Linderoth, Lippert and Østergaard13} Dispatchers also claimed that patients might be evaluated faster if video is established from the beginning of the call.^{Reference Linderoth, Lippert and Østergaard13}

In a large clinical study, the VC was attempted from EMDC in 1.4% of all the real emergency calls and the connection succeeded in 82% of these attempts.^{Reference Linderoth, Lippert and Østergaard13} During a VC, only one-way video transfer is needed from the scene to EMDC.^{Reference Ecker, Lindacher and Adams29,Reference Linderoth, Rosenkrantz and Lippert31,Reference Lee, Kim and Lee32} Practical approach is to send a text message with a link from an EMDC. Clicking on the link enables the phone camera and starts a video transmission to the EMDC in addition to the voice call. No specific application on the caller’s video-capable phone is needed.^{Reference Ter Avest, Lambert and de Coverly12,Reference Linderoth, Lippert and Østergaard13,Reference Linderoth, Rosenkrantz and Lippert31} Text links also enable the use of two mobile phones (one for voice call, one for image transfer).^{Reference Linderoth, Lippert and Østergaard13} This approach seems better than to interrupt the initial call and start a new video call.^{Reference Lee, Song and Shin33,Reference Lee, You and Jeon34}

Two or more bystanders are helpful to obtain optimal side view on the patient or from above the patient.^{Reference Ter Avest, Lambert and de Coverly12,Reference Linderoth, Lippert and Østergaard13,Reference Strauss, Corbin, Denzin and Lincoln28,Reference Lee, Song and Shin33,Reference Lee, You and Jeon34} Moreover, at least two bystanders on site were a condition to establish VC in all presented clinical observations.^{Reference Ter Avest, Lambert and de Coverly12,Reference Linderoth, Lippert and Østergaard13,Reference Linderoth, Rosenkrantz and Lippert31,Reference Lee, Song and Shin33,Reference Lee, You and Jeon34}

Majority of the simulation studies were performed under ideal technical conditions.^{Reference Stipulante, Delfosse and Donneau9,Reference Ecker, Lindacher and Adams29,Reference Kim, Kim and Park30,Reference Lee, Kim and Lee32,Reference Bang, Cho, Cho, Lee and Kim35} However, also relatively low image quality and bad environmental and light conditions seemed to be sufficient for informational transfer and possibility to identify the errors by dispatchers.^{Reference Ecker, Wingen, Hamacher, Lindacher, Böttiger and Wetsch36,Reference Melbye, Hotvedt and Bolle37} A loss of the video connection can occur during VC in the real emergencies,^{Reference Ter Avest, Lambert and de Coverly12,Reference Linderoth, Lippert and Østergaard13} but this has not been mentioned as limitation in the studies conducted in metropolitan areas covered by an advanced mobile network.^{Reference Lee, Song and Shin33,Reference Lee, You and Jeon34}

General callers’ experiences were positive towards the live video transmission (non-stressful, safe, improved communication and description of situation, and easy to use).^{Reference Ter Avest, Lambert and de Coverly12,Reference Linderoth, Lippert and Østergaard13} The option of VC seems to be refused rarely by the callers.^{Reference Ter Avest, Lambert and de Coverly12,Reference Linderoth, Lippert and Østergaard13} Despite generally positive acceptance of the video calls, some Basic Life Support educated callers were afraid of possible delay of the interventions.^{Reference Kim, Kim and Park30} Moreover, 12.5% of respondents thought it was difficult to establish the video connection with a dispatcher given the stressful circumstances.^{Reference Linderoth, Lippert and Østergaard13} Besides activating the link for video, they also must activate the loud-speaker function and accept transmission of video.^{Reference Linderoth, Lippert and Østergaard13} The callers willingness to accept the VC gradually increased during a study period of three months with a broad concomitant public promotion.^{Reference Lee, You and Jeon34} In a clinical study, the bystanders were more compliant and CPR with dispatcher assistance was provided in 76.3% of the audio group as compared to 82.7% of the video group.^{Reference Lee, Song and Shin33} In addition, VC instructions can ensure the caller that the efforts are provided accurately.^{Reference Kim, Kim and Park30,Reference Linderoth, Rosenkrantz and Lippert31}

The callers have been asked to confirm their consent to share their location and stream video from their mobile phone camera and ensured that no video recordings from streamed images will be stored (on a third party server or caller’s phone) and that there is no possibility to access the caller’s phone in some clinical trials.^{Reference Ter Avest, Lambert and de Coverly12,Reference Linderoth, Lippert and Østergaard13,Reference Linderoth, Rosenkrantz and Lippert31} Details regarding caller consent to image transmission in other clinical trials were not founded.^{Reference Lee, Song and Shin33,Reference Lee, You and Jeon34} In general, the questions and analyses of the confidentiality and security of image transmission from the site were not addressed in detail by any of the presented clinical studies.^{Reference Ter Avest, Lambert and de Coverly12,Reference Linderoth, Lippert and Østergaard13,Reference Linderoth, Rosenkrantz and Lippert31,Reference Lee, Song and Shin33,Reference Lee, You and Jeon34}