Two New Effective Tourniquets for Potential Use in the Military Environment: A Serving Soldier Study.

Abstract

Limb tourniquets have been used extensively during modern Middle Eastern conflicts. Despite its undeniable successes, the combat applied tourniquet (C-A-T) has some shortfalls, principally its inability to reliably control lower limb bleeding when applied to the mid-thigh. We tested two tourniquets which may represent an improvement to the combat applied tourniquet; the tactical mechanical tourniquet and the tactical pneumatic tourniquet. We recruited 12 healthy service personnel and applied the tactical mechanical tourniquet and tactical pneumatic tourniquet to both lower limbs in a randomly generated sequence. Tourniquets were tightened until popliteal artery occlusion. This was measured via a SonoSite portable ultrasound machine by a single consultant vascular radiologist familiar with its use. A longitudinal view of the popliteal artery was obtained, and Doppler waveform monitored. The tourniquets were tightened around volunteers' mid-thigh by a second researcher accustomed with their use. Time to complete occlusion, number of windlass revolutions, and pain scores were collected by a third researcher. Non-normally distributed data are present as median (interquartile range). Ordinal nonparametric data are analysed by Mann-Whitney U testing. Participants had a median age of 32.5 (28-35). Both tourniquets demonstrated complete occlusion of the popliteal artery in all limbs (n = 24). The mechanical tourniquet achieved arterial occlusion after a median of 3.8 (3-4) turns, and 16 (12-20) seconds. No participants dropped out of the study because of intolerable pain, or any cause. Median pain scores for the mechanical tourniquets were 4.5 (3-7) (maximum pain) and 4.0 (2-7) (pain when locked). Median pain scores for the pneumatic tourniquet were 5 (2-6) (maximum pain) and 5 (2-6) (pain when fully applied). There was no statistical difference in maximum pain scores between the tactical mechanical tourniquet and the tactical pneumatic tourniquet (p = 0.75). No participant had any tourniquet applied for longer than 80 seconds. Both tourniquets completely occluded the popliteal artery in all participants within an acceptable pain threshold. Further testing is required before the presented tourniquets can be taken to the battlefield; particularly measures of self-application, and use on other anatomical areas.