Remote Guidance for eFAST Training Using a Head-Mounted Device: A Three-Arm Randomized Simulation Study
Remote Guidance for eFAST Training Using a Head-Mounted Device: A Three-Arm Randomized Simulation Study
This study looks at the best way to remotely teach and guide doctors-in-training to perform a bedside ultrasound exam called eFAST (extended Focused Assessment with Sonography for Trauma), which is used to quickly check injured patients for internal bleeding or air around the lungs.
The study takes place in a simulation setting, with no real patients. Resident physicians who have completed the basic ultrasound courses each watch the same short instructional video and then perform three eFAST examinations on the same healthy volunteer. Participants are randomly assigned to one of three groups: (1) the instructional video only, with no live help; (2) the video plus real-time audio guidance from a remote expert who can see the live ultrasound image; or (3) the video plus guidance through a head-mounted device that also lets the expert see the participant's own point of view.
Afterwards, experts who were not involved in a given exam review the recorded ultrasound images, without knowing which group the participant was in, and rate the image quality and skill. The study also measures how long the exams take, the participants' workload, and the comfort and usability of the system.
The goal is to learn whether real-time remote guidance, and in particular guidance through a head-mounted device, helps trainees produce better and faster eFAST examinations than an instructional video alone.
Background and rationale: eFAST is a highly operator-dependent skill, and remote (tele-ultrasound) guidance is increasingly used to extend expert support to less-experienced operators. Hands-free head-mounted devices may improve remote mentoring by giving the expert the operator's point of view, but there are no data on their use for eFAST training. This single-center, simulation-based, three-arm randomized controlled study compares three remote-guidance modalities.
Setting and allocation: The study runs in a standardized simulation environment with no patients. Allocation to the three arms is 1:1:1 using permuted blocks with concealed allocation via the REDCap randomization module, with the assigned arm revealed only at the session. After a standardized instructional video and a brief ultrasound-system introduction, each participant performs three consecutive complete eFAST examinations on the same standardized healthy volunteer, under standardized environmental conditions to minimize anatomical and contextual variability.
Technical setup: Examinations use a GE LOGIQ E10s (R4) with an M5Sc-D matrix sector probe. The native ultrasound image is sent over a secure connection to a dedicated study laptop that joins a Microsoft Teams call, so the remote expert sees the live image in real time; in the head-mounted-device arm the participant's point-of-view video is additionally transmitted. Probe motion (optical tracking) and a depth (RGBD) camera are recorded for exploratory workflow analyses, with shared time-stamps used to synchronize the data streams. Live audio is not recorded.
Assessment workflow: The entire scan is recorded continuously; the participant verbally marks each window, and window-specific clips are extracted retrospectively from these time-stamps and pseudonymized. Experts who did not supervise a given examination review the clips while blinded to group allocation, and each scan is reviewed by two independent experts to support an inter-rater reliability estimate. The participating experts also perform on-site benchmark eFAST examinations as a reference.
The study is designed in line with SPIRIT and reported in line with CONSORT 2025.
Inclusion Criteria:
Exclusion Criteria:
Nicola.Cavalcanti@balgrist.ch+41 44 510 73 60
Philipp.fuernstahl@balgrist.ch+41 44 510 73 60