Automated Hemorrhage Control Device

Current REBOA solutions occlude the vessel by inflating a balloon internally and creating a seal against the endothelium. By partially deflating the balloon, a reduced flow state can be accomplished to allow perfusion of distal tissue and mitigate ischemic injury, but this has been difficult to manage. Fluid dynamics show that flow restriction through an orifice is linearly proportional to its cross sectional area. As the cross sectional area doubles, so does the flow. However, the cross sectional area of a circle is exponentially proportional to its radius, so small changes in diameter of a fully inflated REBOA balloon cause extreme changes in flow. Due to the compliance of the balloon and vessel wall, this makes the flow rate extremely difficult to manage at high inflation volumes (i.e. the low flow rates desired in these scenarios). Our solution changes the locus of flow control from the external surface of the occluding balloon to an interior lumen created by using a concentric set of toroidal balloons. This provides higher sensitivity of flow control at lower flow rates. We propose to create this method of occlusion by replicating the physical characteristics of an orifice plate commonly used in industrial hydraulic flow control using concentric balloons. To increase the performance of our system further, we will monitor the blood pressure differential across the occlusion and vary the orifice diameter with automated controls in a closed feedback loop to maintain a consistent flow rate during changing hemodynamics. Blood pressure will be sensed through two membranes on the distal end of the catheter and translated through a sterile fluid to sensors integrated in the proximal end; external to the body. This will be a fully sealed system, simplifying setup and deployment of the device in the field. Testing will be performed in an in vitro hemorrhage model and compared against commercially available equipment to ensure it meets or exceeds the specifications set by association for the Advancement of Medical Instrumentation. During this study, data will be collected and presented to our clinical team to identify clinical and technological issues that may require switching from automated to manual operation. This system will include a simple graphical user interface (GUI) and be suitable for use in austere, pre-hospital settings.