Concept and Material Development in Tourniquet Research for Impaled Object Hemorrhage
Abstract:
The objective of this study was to develop simulation materials and wound-hemorrhage concepts for one-handed self-application of a tourniquet to an impaled limb. Methods: 2D and 3D ways of simulating impaled limbs were constructed to challenge first-aid use of tourniquets. In 2D assessments, graph papers, cardboard cutouts, strings, and kabob skewers mimicked cross-sectional planes of limbs, limb girths, loops of tourniquet band, and impaled objects, respectively. For 3D assessments, an investigator used one hand to apply a tourniquet. Results: 2D assessments were made rapidly and repeatedly to indicate whether loop passage was easy. The easy-difficult boundaries were identified for varied configurations of girths, skewers, boot outlines, and garment cutouts; loops stretched to the limit to pass around objects identified boundaries. Challenges to passage which were conjunctive (multiple, concurrent) readily worsened scenarios. In 3D assessments in use of tourniquets, loops for actual tourniquets were opened and passed. For 30 Combat Application Tourniquets (C-A-T), loop size averaged 69.8 cm. For 24 Special Operations Forces Tourniquet, loop size averaged 62.0 cm; instructions denote that the loop is sized to pass over the users arm. For one C-A-T, loop circumference was varied by reconfiguring the loop, and its circumference was decreased incrementally by approx. 1 cm in 30 assessments from 69.7 cm to 37.3 cm; ease of passage was initially very, very easy (7/7) but eventually became very, very difficult (1/7). Discussion: In both 2D and 3D, geometry helped in understanding loop passage and its troubleshooting. Developed concepts included: performance metrics of loop passage, loop size comparisons to limb girths, and loop passage in multiple, concurrent challenges. A caregiving gap was discovered: a proportion of Soldiers may be unable to pass a tourniquet loop to their proximal thigh, indicating that troubleshooting methods may need to be developed and taught.