Towards a Novel Wearable Robotic Vest for Hemorrhage Suppression

TL;DR

The paper tackles hemorrhage control in space and other remote settings by introducing a wearable robotic vest with a shape-changing ring mechanism, an inflatable ring, and an airbag balloon to deliver constant, localized pressure to non-extremity wounds. It combines a mechanical model based on Castigliano's theorem with experiments to evaluate bending stiffness across ring-arm designs, burst pressures of inflatable components, and the device’s ability to apply pressure on surfaces and stop simulated bleeding on a torso model. Key contributions include identifying the ridge ring-arm design as the most flexible, quantifying burst pressures ($16.55\ \mathrm{kPa}$ for the ring and $18.62\ \mathrm{kPa}$ for the balloon), validating force transmission against contact areas, and demonstrating casualty-model efficacy at relevant pressures. The work presents a portable, reusable approach that could enhance autonomous hemorrhage control in space and remote environments, with clear paths for improving torque, conformability, and handheld usability in future iterations.

Abstract

This paper introduces a novel robotic system designed to manage severe bleeding in emergency scenarios, including unique environments like space stations. The robot features a shape-adjustable "ring mechanism", transitioning from a circular to an elliptical configuration to adjust wound coverage across various anatomical regions. We developed various arms for this ring mechanism with varying flexibilities to improve adaptability when applied to non-extremities of the body (abdomen, back, neck, etc.). To apply equal and constant pressure across the wound, we developed an inflatable ring and airbag balloon that are compatible with this shape-changing ring mechanism. A series of experiments focused on evaluating various ring arm configurations to characterize their bending stiffness. Subsequent experiments measured the force exerted by the airbag balloon system using a digital scale. Despite its promising performance, certain limitations related to coverage area are identified. The shape-changing effect of the device is limited to scenarios involving partially inflated or deflated airbag balloons, and cannot fully conform to complex anatomical regions. Finally, the device was tested on casualty simulation kits, where it successfully demonstrated its ability to control simulated bleeding.

Figures (9)

• Figure 1: Overall wearable robot design with labeled components.
• Figure 2: Configurations of the wearable robot, (a-1) Design model in the circular configuration for addressing circular wound, (a-2) Design model in the elliptical configuration for linear wound, (b-1) Actual implementation of the robot in the circular configuration, (b-2) Actual implementation of the robot in the elliptical configuration.
• Figure 3: Midsection ring, (a) a layered schematic illustrating the order of each layer (b) the inflated ring configuration.
• Figure 4: The airbag balloon, (a) a layered schematic illustrating the different layers used, (b) translucent inflated airbag balloon showing all the internal and external components.
• Figure 5: (a) The ring arm shown as an arc-shaped curve (in $x-y$ plane) subjected to the perpendicular force $P$ (in $-z$ direction) at its tip ($x=R$) and mechanically secured at the base ($y=R$), (b) the 3 characterized ring arms: Standard, Cutout, and Ridges, (c) the isolated ring arm experimental setup.