Hemostatic Compression Device Jill Doyle Reed Gioe Christopher Miller Aut Singhchinsuk

Problem Statement: No device is currently available for untrained people to safely apply pressure to an open bleeding wound for extended periods of time. 1. Must be a “one-hand solution” with no training required 2. Device must be compact for storage 3. Must apply enough compressive force to obtain hemostasis 4. Must provide a visual indication when correct pressure is achieved Design Goals: 5. Must distribute force in a way that will maximize pressure applied to the wound and minimize constriction of blood flow

Selection CriterionConnectionPressureBand VelcroPressure Pump BuckleZipperMetal Mesh Foldable Rod Network Multiple Bands Single Band Ease of Manufacture Ease of Use Cost Ability to Evenly Distribute Forces Size (when packaged) Sum +’s Sum –‘s Sum 0’s Net Score Rank Continue?YesNoYesNoYes NoYes

Device Concept

Device Components Does material choice matter? Do different materials yield different pressure gradients?

Focus on Force Distribution for Experimental Design ●Force should be concentrated over the wound ●Device should not form a tourniquet around the limb ●Most common laceration size is 2.5 to 5 cm ●Force should be concentrated over the wound ●Device should not form a tourniquet around the limb ●Most common laceration size is 2.5 to 5 cm ●Added trial: rigid piece on curved test surface ●Rearranged force sensors ●Modified and simplified device for testing ●Added trial: rigid piece on curved test surface ●Rearranged force sensors ●Modified and simplified device for testing Force should be concentrated over the wound Device should not form a tourniquet around the limb Most common laceration size is 2.5 to 5 cm We should test multiple materials of varying shape We should take into consideration constriction of blood flow upon analysis We should look for force concentrated in a small area for this wound type Question: How does the shape and property of a material influence the force distribution?

Experiments planned to show material effects Conclusion Most successful compression support would be selected for final prototype Expected results Force distribution gradient Experiment Variables: type of structural material and type of testing surface Conclusion Material best satisfying design criteria will be selected Analysis Comparison of force distribution gradients Experimental Results Force distribution gradient Experiment Variable: type of structural material

Force-sensing resistors in voltage divider circuit give reduced voltage when force is applied Force Reduced Voltage Input: Output:

Rigid Testing Surfaces Material Choices Tested 3 materials on 3 surfaces Rigid PieceMetal MeshGauze Flat surface  Foam surface  Arm  Mesh Flat Foam Arm

Material choice matters for force distribution. Rigid PieceMetal MeshGauze Flat Foam Arm

Different materials produce different force distributions and magnitudes of force ● Force in rigid piece concentrated in center; largest amount of force present. ● Force in mesh concentrated around the edges; smaller magnitude of force than rigid piece. ● Force in gauze piece unevenly distributed across surface; weakest magnitude of force among materials tested.

● Rigid piece provided greatest magnitude of force in a targeted area ● Flat piece concentrates force on top and bottom of arm, reducing possibility of tourniquet formation ● Localized force from rigid piece optimal for most common wound type Rigid piece best fits original design criteria ●Force should be concentrated over the wound ●Device should not form a tourniquet around the limb ●Most common laceration size is 2.5 to 5 cm Force should be concentrated over the wound Device should not form a tourniquet around the limb Most common laceration size is 2.5 to 5 cm Rigid piece provided greatest magnitude of force in a targeted area Rigid piece concentrates force on top and bottom of arm, reducing possibility of tourniquet formation Localized force from rigid piece optimal for most common wound type

Rigid piece is most optimal material for our design ● Sources of error: ○Force may have been deceptively distributed in places without force sensors ○Assumptions about weight and force distribution ● Future direction: ○Test more shapes of rigid pieces ○Test different limb circumferences ○Test and calibrate the tension indicator Proposed final design based on experimental results Allows connection to strap Flat, rigid surface