Across Tourniquet Designs First-Use Learning.

Background: We hypothesized shared-design tourniquet features have useful first-use learning when knowledge-of-results occurs.

Methods: In a prior study, after watching training videos, 64 volunteers were videoed applying (Latin squares randomization): Combat Application Tourniquet Generation 7 ™ (CAT7), SOF ™ Tactical Tourniquet-Wide Generation 3 (SOFTTW3), SOF™ Tactical Tourniquet-Wide Generation 5 (SOFTTW5), Tactical Mechanical Tourniquet® (TMT), OMNA Marine Tourniquet™ (OMT), X8T-Tourniquet (X8T), Tactical Ratcheting Medical Tourniquet™ (Tac RMT), and RapidStop® Tourniquet (RST). Tourniquets were applied to live thighs with audible distal Doppler pulses.

Results: This study subset was 10 experienced and 33 no-experience appliers. Experienced appliers had fewer strap/redirect and fewer tightening-system understanding problems and faster associated times than no-experience appliers. Among no-experience appliers, firstuse learning was supported by faster "Go" to "strap secured" times for combined seventh and eighth versus first applications (p=.008), secondversus first-encounter CAT7/OMT applications (p=.0005), and secondversus first-encounter SOFTTW3/ SOFTTW5 applications (p=.079). Occlusion at "Done" was more frequent with experienced appliers (p=.006) and did not show first-use learning across all tourniquets in no-experience appliers. Occlusion at "Done" indicated possible first-use learning with ratcheting-buckle versus windlass-rod tightening systems (p=.028, no-experience appliers). Hook-and-loop strap security, which provides no inherent knowledge-of-results, showed no learning in experienced (five problem applications by two appliers) or no-experience appliers (29 problem applications by 18 appliers).

Conclusions: Knowledge-of-results is critical for, but does not guarantee, tourniquet-application-useful first-use learning. The existence of first-use learning can allow limited experience with one tourniquet to improve performance with a different tourniquet with shared-design features. Therefore, exposure to different designs may have value, and providing tourniquet-training knowledge-of-results is important.