J Spec Oper Med. Summer 2018;18(2):36-41.

# New and established models of limb tourniquet compared in simulated first aid.

Kragh JF Jr, Newton NJ, Tan AR, Aden JK 3d, Dubick MA.

BACKGROUND: The performance of a new tourniquet model was compared with that of an established model in simulated first aid.

METHODS: Four users applied the Combat Application Tourniquet (C-A-T), an established model that served as the control tourniquet, and the new SAM Extremity Tourniquet (SXT) model, which was the study tourniquet.

RESULTS: The performance of the C-A-T was better than that of the SXT for seven measured parameters versus two, respectively; metrics were statistically tied 12 times. The degree of difference, when present, was often small. For pretime, a period of uncontrolled bleeding from the start to a time point when the tourniquet first contacts the manikin, the bleeding rate was uncontrolled at approximately 10.4mL/s, and for an overall average of 39 seconds of pretime,

406mL of blood loss was calculated. The mean time to determination of bleeding control (± standard deviation [SD]) was 66 seconds (SXT, 70 ± 30 seconds; C-A-T, 62 ± 18 seconds; p = .0075). The mean ease-of-use score was 4 (indicating easy) on a scale of 1 to 5, with 5 indicating very easy (mean ± SD: SXT, 4 ± 1; C-A-T, 5 ± 0; p < .0001). C-A-T also performed better for total trial time, manikin damage, blood loss rate, pressure, and composite score. SXT was better for pretime and unwrap time. All users intuitively self-selected the speed at which they applied the tourniquets and that speed was similar in all of the required steps. However, by time segments, one user went slowest in each segment while the other three generally went faster.

CONCLUSIONS: In simulated first aid with tourniquets, better results generally were seen with the C-A-T than with the SXT in terms of performance metrics. However, the degree of difference, when present, was often small.