Assessing the Current Generation of Tourniquets.

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Tourniquet application is an urgent life-saving procedure. Previous studies demonstrated several drawbacks in tourniquet design and application methods that limit their efficacy; among them, loose application of the device before windlass twisting is a main pitfall. A new generation of modern combat tourniquets was developed to overcome these pitfalls. The objective of this study was to assess the effectiveness of three new tourniquet designs: the CAT Generation 7 (CAT7), the SAM Extremity Tourniquet (SAM-XT), and the SOF Tactical Tourniquet Wide (SOFTT-W) as well as its correlation to the degree of slack. The three tourniquet models were applied in a randomized sequence on a HapMed leg tourniquet trainer, simulating an above-the-knee traumatic amputation by 60 military medicine track cadets. Applied pressure, hemorrhage control status, time until the bleeding stopped, estimated blood volume loss, and slack were measured. The mean (±SD) pressure applied using the SAM-XT (186mmHg ±63) or the CAT7 (175mmHg ±79) was significantly higher compared to the pressure applied by the SOFTT-W (104mmHg ±101, P<0.017), with no significant difference between the first two (P>0.05). Hemorrhage control rate was similar (P>0.05) with SAM-XT (73.3%) and CAT7 (67.7%), and both were significantly better than the SOFTT-W (35%, P<0.017). Slack was similar between CAT7 and SAM-XT (5.2mm±3.4 vs. 5mm±3.5, P>0.05), yet significantly lower compared to the SOFTT-W (9mm±5, P<0.017). A strong negative correlation was found between slack and hemorrhage control rate (3.2mm±1.5mm in success vs. 10.5mm±3.4mm in failure, P<0.001) and applied pressure (Pearson's correlation coefficient of -0.83, P<0.001). Both SAM-XT and CAT7 demonstrated a better pressure profile and hemorrhage control rate compared to SOFTT-W, with no significant difference between the two. The better outcome measures were strongly correlated to less slack.