Role of the Windlass in Improvised Tourniquet Use on a Manikin Hemorrhage Model.

BACKGROUND In emergencies when commercially designed tourniquets are unavailable, hemorrhage may need to be controlled with improvised tourniquets. In the aftermath of the Boston Marathon bombing, no improvised strap-and-windlass tourniquets were used to treat casualties; tourniquets without windlasses were used. The purpose of the present study is to determine the effectiveness of improvised tourniquets with and without a windlass to better understand the role of the windlass in tightening the tourniquet strap. METHODS An experiment was designed to test the effectiveness of improvised strap-and-windlass tourniquets fashioned out of a tee shirt on a manikin thigh. Two users conducted 40 tests each with and without the use of a windlass. RESULTS Without a windlass, improvised tourniquets failed to stop bleeding in 99% of tests (79 of 80 tests). With a windlass, improvised tourniquets failed to stop bleeding in 32% of tests (p < .0001). In tests with no windlass, attempts to stop the pulse completely failed (100%, 80 of 80 tests). With a windlass, however, attempts to stop the pulse failed 31% of the time (25 of 80 tests); the difference in proportions was significant (p < .0001). CONCLUSIONS Improvised strap-and-windlass tourniquets were more effective than those with no windlass, as a windlass allowed the user to gain mechanical advantage. However, improvised strap-and-windlass tourniquets failed to control hemorrhage in 32% of tests.