Final result after creating the DIY CrashSavers Simulator.
Medical knowledge page data
Required time 45-90 minutes Simple Version15-20 hours Extended Version CrashSavers DIY Tourniquet Simulator
Device data
Making instructions Video instructions Document CERN-OHL-S Start OSHWA certification
Medical equipment data

In this page you will find all the instructions necessary to build your own CrashSavers DIY. Tourniquet Simulator.

## Prototyping and Iterations

The simulator was formulated by an engineering team that created 9 iterations and prototypes to lead to the final simulators. The engineers reported advances every week and created a report for each prototype delivery. Two final versions of the simulator were created, a simple and an advanced version. The advanced version of the simulator differs from the simple version because it includes an Arduino sensor that incorporated a pressor sensing component to the model. This allows for the model to sense the total pressure that is applied to the simulator, and feeds this information back to the user through the VR app.

A Note on Design Replicability and Risk

We specifically include both versions of the simulator on this instructional page so that the end-users can build and utilize the version that they find preferable. While there is great value in the advanced version of the simulator, we received feedback from initial users as well as Global Surgical Training Challenge Judges during the Prototype Showcase that this may prove complicated for potential users who did not have engineering experience. Because of this feedback, we created a simpler version of the simulator that does not incorporate the pressure sensor and relies primarily on a pump-based mechanism. We believe the simple version provides a higher fidelity option for creating a readily reproducible simulator and avoids the risk of electrical mishaps or confusion with the sensor-based model if the users are wary or apprehensive of this component of the simulator.

Evolution of the Simple version

## Simple version

This version is easier, quicker, and cheaper to build. It is not directly connected to the app, but there is a data collection checklist included in the app that assesses the user's ability to correctly apply and utilize a tourniquet. [1].

### Building manual

The following instructions guide the learner to build our simple, fast and cheap lower extremity simulator for correct tourniquet application. After completion of the skill, the user can continue through the clinical case scenarios in the CrashSavers VR App and evaluate their performance.

Click to access the building manual. In this document, the learner will find all materials, pricing, online providers, and step-by-step instructions for building the simulator. Also, the manual includes recommendations.

### Video instructions

Annotations:
• 00:00 - Introduction
• 00:04 - ¿How to build the mechanism?
• 00:07 - PVC Cuts
• 01:29 - Mechanism building
• 03:16 - Fluid System

The basic parts of the simple version are maintained, but an advanced electronic mechanism was created to simulate arterial blood flow and sense changes in pressure as the learner applies the tourniquet. This information is analyzed by an Arduino. When the user achieves the correct pressure with the tourniquet to stop the flow of blood, the Arduino sends a signal to the VR App that the task has been adequately completed. The user then can continue the clinical case within the VR App.

### Building manual

With these instructions a lower extremity simulator can be built that will simulate and sense the adequate pressure needed for correct tourniquet application. After completion, this information will be sent to the Crashsavers VR application so the user can continue through the clinical case scenarios.

Click to access the building manual. In this document, the learner will find all materials, pricing, online providers, step-by-step instructions, and blueprints for building the simulator. Also, the manual includes recommendations for assembly and online support if necessary.

We understand that users can have difficulties working with electronics. In the manuals, we include recommendations for assembly and online support if necessary. Moreover, our goal is to create a Printed circuit board (PCB) that will let us create a simplified modular version of the simulator so users can assemble it more easily.

### Video instructions

Annotations:
• 00:00 - Introduction
• 00:04 - ¿How to build the mechanism?
• 00:08 - Material Preparation
• 02:40 - Mechanism building
• 04:26 - Fluid System
• 04:48 - Electronic System

### Connecting the Advanced Simulator with the VR App

After building the simulator, it can be connected to the Crashsavers VR App for a realistic experience on hemorrhage control techniques. Here the user will find step by step instructions on how to achieve an adequate connection for usage:

Android devices:

1. Open Settings on your device and go to Connections.
2. Tap on Bluetooth and turn it on.
3. Search for devices.
4. Tap on the device named "Crashsavers Simulator".
5. Simulator paired.
6. Open CrashSavers VR App.
7. Use on clinical cases when feasible.

Apple devices:

1. Open Settings on your device.
2. Tap on Bluetooth and turn it on.
3. Search for devices.
4. Tap on the device named "Crashsavers Simulator".
5. Simulator paired.
6. Open CrashSavers VR App.
7. Use on clinical cases when feasible.

## Building Time, Material Costs, and Value for Money

All materials needed to create the simulator were chosen due to their ready availability worldwide. All the materials were easy to find in local stores in Guatemala and many have been listed on online stores for ease of build. We have not identified any comparable physical model or hemorrhage control training module that provides as comprehensive an educational experience at this price point.

Building time and costs of both versions of the CrashSavers DIY Tourniquet Simulator
Building time 45 - 90 minutes 15-20 hours
Costs $50.00 aprox.$94.00 aprox.

## Reproducibility

We are conscious and mindful of the need for easy reproducibility of our model in order for it to be appropriately used by learners at many different abilities and experience levels. This was addressed by cloning the simulator twice with two different groups - the initial engineers who created the device, and the firefighter trainees. We asked the firefighters to assemble the simulator without any assistance. They reported that the simple simulator was straightforward to build without engineering background, expertise, or experience, and was able to complete the build in 1.5 hours. Here we share their experience:

## References

1. Weinman, S. (2020). Retention of Tourniquet Application Skills Following Participation in a Bleeding Control Course. Journal of Emergency Nursing, 46(2), 154–162. https://doi.org/10.1016/j.jen.2019.10.020