Development of the fully immersive VR simulation

To realistically recreate a medical procedure in VR, we have to understand its basic steps, actions, and milestones. The best way to obtain such a breakdown analysis is to consult professionals specialized in this method. In our case, the Subject Matter Experts material, required for the design of a complete storyboard tailored for the REBOA VR training module, was provided by our medical experts (TB, WEH, TCS) to the development team of ORamaVR (Geneva, Switzerland), according to the methodology published in [25].

The simulated environment consisted of an emergency theatre including a virtual patient, who is hemodynamically unstable after a motor vehicle accident with free fluid in the abdomen. Clinical information, vital signs, ultrasound, or X-ray images, as well as information on the next steps are displayed on monitors in the virtual emergency room. A sterile covered table is used to store and prepare the required materials. The insertion of the REBOA catheter is performed step by step on a virtual person. These steps include.

1.

Decision on placement depth and measurement for zone 1 REBOA using the clinical information

2.

Preparation of femoral arterial access

3.

Cannulation of the common femoral artery using ultrasound

4.

Guidewire introduction

5.

Placement of sheath

6.

REBOA catheter preparation

7.

REBOA catheter insertion

8.

Balloon inflation and confirmation of its effect

9.

Fixation of catheter

10.

Chest X-ray

Screenshots of the simulation are detailed in Figs. 1 and 2.

Fig. 1

Screenshot of the VR REBOA simulation. Preparation of the sheath, adaptable view into the torso

Fig. 2

Screenshot of the VR REBOA simulation. Patient monitorized in the resuscitation bay, REBOA catheter in situ after successful insertion

Two modes of action were available for single-player use: In the tutorial mode visual aids and prompts helped the trainees in providing information on the next procedural step; these prompts were missing in the normal mode.

Study design, setting, and ethical approval

This is a prospective feasibility pilot study involving prehospital emergency physicians and emergency paramedics of the “Schutz und Rettung Bern” [23]. The study was conducted at the University Emergency Department (Universitätsklinik für Notfallmedizin) at the Inselspital, University Hospital, Bern, Switzerland. The study took place from November 2020 until March 2021.

This study was exempt from full ethical review by the local institutional review board (Kantonale Ethikkommission Bern (Ethics Committee Bern), BASEC-No: Req-2020-00970). Written informed consent for study participation was obtained from all participants. Written informed consent from a parent and/or legal guardian is “not applicable”. Consequently, the present study was conducted in accordance with the ethical standards of the 1964 Declaration of Helsinki and its subsequent amendments.

Participants

The local prehospital emergency medical services (“Schutz und Rettung Bern”) are carrying out about 23,000 preclinical medical emergency operations annually. There are 17 emergency physicians and 108 paramedics (50% female) working in a rendezvous system. All participants were offered and attended the training on a voluntary basis and we provided no remuneration. Written informed consent was obtained for the study and publication of the study results. Written informed consent from a parent and/or legal guardian is “not applicable”.

Baseline data

Sociodemographic data (gender, age, profession (physician/paramedic), working experience in years, need to wear eyeglasses, right/left-handedness), prior training and experience in REBOA as well as prior experience with VR, were collected in a survey.

Intervention

Initially, three peer teachers were introduced to the VR set-up and the correct operation of the REBOA VR module by the development and study team of the University Emergency Department (TS, TB, JB) in a 2-h training session, who then passed on their knowledge and were able to train their peers (“teach the teacher”). The REBOA VR simulation station was set up in an empty room at the Schutz und Rettung headquarter Bern (Fig. 3). The hardware consisted of a stand-alone VR headset with two hand-held controllers (Oculus Quest, Oculus VR, Facebook Inc., Menlo Park, CA, USA) and a tablet pc. The REBOA module, version 1.2.6, software platform, developed by ORamaVR (Geneva, Switzerland), was used in the single-player tutorial and normal mode.

Fig. 3

Setup of the VR simulation. Setup for the VR REBOA simulation including hand-held controllers, head-mounted device (Oculus Quest), tablet PC, disinfection materials

During 5 months, from November 2020 to March 2021, paramedics and preclinical emergency physicians had the opportunity to train with the VR simulation on their own after being instructed by the trained peer instructors during their shifts or whenever was a suitable timeslot for them. The peer instructors had the opportunity to follow the simulation on the tablet PC, and thus to provide additional targeted assistance, apart from the automated feedback by the tutorial mode of the software, if necessary.

Outcome measuresAcceptance of the VR simulation

Evaluation of acceptance of the VR simulation was carried out according to established questionnaires directly after the VR training.

Usability

Usability was assessed using the System Usability Scale (SUS) [26], which is composed of 10 questions with a 5-point Likert attitude scale and the After-Scenario Questionnaire (ASQ) [27], which assesses the ease of task completion, satisfaction with completion time and satisfaction with supporting information on a 7-point Likert scale (total score ranges from 1 = full satisfaction to 7 = poor satisfaction).

Simulator sickness

“Visually-induced motion sickness” was assessed with four items (The VR training caused nausea/headache/blurred vision/dizziness) taken from the Simulator Sickness Questionnaire (SSQ) from Kennedy et al. (Likert scale from 1 = totally disagree to 5 = totally agree) [28].

Sense of presence and immersion

Presence and immersion in the virtual world were determined according to the 6-item questionnaire developed by Slater-Usoh-Steed (total score ranges from 1 = no immersion to 7 = full immersion) [29].

Workload

Perceived subjective workload on a scale from 0 to 100 was assessed using the NASA-Task Load Index (NASA-TLX) as a total score and within 6 subdomains [30]. Overstraining is associated with a total score > 60, and understraining with a total score of < 37 [31].

User satisfaction

The User Satisfaction Evaluation Questionnaire (USEQ) has six questions with a 5-point Likert scale to evaluate user satisfaction (total score ranges from 6 = poor satisfaction to 30 = excellent satisfaction) [32].

Furthermore, free-text comments were collected.

Subjective effectiveness/confidence

Confidence in the correct performance of the REBOA intervention was assessed before and after the training (“I feel confident in conducting the REBOA intervention correctly” (Likert scale from 1 = totally disagree to 5 = totally agree).

Statistical analysis

Data was analyzed using SPSS.

Baseline characteristics are presented as numbers and percentage or median and interquartile range (IQR) using descriptive statistics as appropriate. Pre- and post-simulation comparisons were performed with the Wilcoxon signed rank test. A p value < 0.05 was considered significant.