No slackers in tourniquet use to stop bleeding.

BACKGROUND: Tourniquets on casualties in war have been loose in 4%?9% of uses, and such slack risks death from uncontrolled bleeding. A tourniquet evidence gap persists if there is a mechanical slack?performance association. OBJECTIVE: The purpose of the present study was to determine the results of tourniquet use with slack in the strap versus no slack before windlass turning, in order to develop best practices. METHODS: The authors used a tourniquet manikin 254 times to measure tourniquet effectiveness, windlass turns, time to stop bleeding, and blood volume lost at 5 degrees of strap slack (0mm, 25mm, 50mm, 100mm, and 200mm maximum). RESULTS: When comparing no slack (0mm) to slack (any positive amount), there were increases with slack in windlass turns (p < .0001, 3-fold), time to stop bleeding (p < .0001, 2-fold), and blood volume lost (p < .0001, 2-fold). When comparing no slack to 200mm slack, the median results showed an increase in slack for windlass turns (p < .0001), time to stop bleeding (p < .0001), and blood volume lost (p < .0001). CONCLUSIONS: Any slack presence in the strap impaired tourniquet performance. More slack had worse results. Trainers can now instruct tourniquet users with concrete guidance.

Single versus Double Routing of the Band in the Combat Application Tourniquet.

BACKGROUND: Common first aid tourniquets, like the Combat Application Tourniquet (CAT) of a windlass and band design, can have the band routed through the buckle in three different ways, and recent evidence indicates users may be confused with complex doctrine. OBJECTIVE: The purpose of the present study is to measure the differential performance of the three possible routings in order to better understand good tourniquet practice. METHODS: A training manikin was used by two investigators to measure tourniquet effectiveness, time to stop bleeding, and blood loss. RESULTS: The effectiveness rate was 99.6% (239/240) overall. RESULTS were similar for both single-slit routings (inside vs. outside, p > 0.05). Effectiveness rates (yes-no results for hemorrhage control expressed as a proportion of iterations) were not statistically different between single and double routing. However, the time to stop bleeding and blood loss were statistically different (p < 0.05). CONCLUSIONS: CAT band routing, through the buckle either singly or doubly, affects two key performance criteria: time to stop bleeding and volume of blood lost. Single routing proved to be faster, thereby saving more blood. Learning curves required to optimize user performance varied over 30-fold depending on which variable was selected (e.g., effectiveness vs. blood loss).